2019 Vol. 32, No. 2
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2019, 32(2): 1-8.
doi: 10.13275/j.cnki.lykxyj.2019.02.001
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Abstract:
Objective To explore the feasibility of dsRNA expressed by HT115-mediated RNAi in Hyphantria cunea. Method Hyphantria cunea chitinase gene (HcChi) was chosen as the target gene. An interference fragment was designed and inserted into the expression vector L4440, and then transformed into the Escherichia coli strain HT115. The H. cunea larvae were fed on bacteria solution which was induced by IPTG. The growth of larvae were observed, and the mRNA level of HcChi was detected using qPCR. Result The HT115 strain containing HcChi-L4440 expression vector can express HcChi-dsRNA by IPTG induction. After fed on bacteria solution, the expression level of HcChi in H. cunea decreased significantly by 76.7%-90.3%. The body weight growth decreased about 40.7% compared with the control. Conclusion The RNA interference vector was constructed successfully. The effect of RNAi was observed in H. cunea by feeding method. This is the first time that developing a method of RNAi based on bacteria expressed dsRNA in H. cunea, which provides a new idea on the study of gene function and biological control of H. cunea.
2019, 32(2): 9-16.
doi: 10.13275/j.cnki.lykxyj.2019.02.002
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Objective To study the induced resistance of two clones of Populus section Aigeiros after oviposition of Micromelalopha sieversi (Staudinger) through observing the effects of the oviposited and neighboring plants on the growth of the larvae and measuring the contents of nutrients and secondary metabolites. Method The survival of larvae feeding on the oviposited, neighboring and controlled leaves of Populus×euramericana 'Guariento' and P.×euramericana 'Bellotto' was observed, then the contents of soluble sugar, total nitrogen, free amino acid, tannin and total phenol in the leaves of three treatments were measured to study the induced resistance of the two clones after oviposition of M.sieversi. Result There was no significant difference inthe survival rate of larval among the three treatments.The content of total soluble sugar in the oviposited and neighboring plants of P.×euramericana. 'Guariento' was significantly lower than that of the control plants. The content of disaccharide and total nitrogen in the oviposited and neighboring plants of P.×euramericana. 'Bellotto' was significantly lower than that of the control plants, and the content of free amino acids in the oviposited plants was significantly lower than that of the control plants.At the same time, the total amount of free amino acids in the neighboring plants of P.×euramericana. 'Guariento' was significantly higher than that of the oviposited and the control plants. The ratio of total sugar to total nitrogen in the oviposited and neighboring plants of P.×euramericana. 'Bellotto' were significantly higher than those of the control plants. The contents of tannin and total phenol in the oviposited plants of P.×euramericana. 'Guariento' were significantly higher than that of the control plants, while there was no significant difference between the neighboring plants and the control plants. The contents of tannin and total phenol in the oviposited plants of P.×euramericana. 'Bellotto' was significantly higher than that in the control plants, and the content of tannin in the neighboring plants was significantly higher than that of the control plants. Conclusion The content of nutrients in the oviposited and neighboring plants of the two clones changed and the content of secondary metabolites increased at different degrees.Therefore, both the oviposited and neighboring plants of the two clones can produce certain induced insect resistance after oviposition of M.sieversi.
2019, 32(2): 17-24.
doi: 10.13275/j.cnki.lykxyj.2019.02.003
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Objective To explore the sprouting phenomenon in the tropical mountain rainforest by investigating species composition, spatial distribution, and factors related to the sprouting characteristics. Method Taking the woody plants (DBH ≥ 1cm) with sprouting phenomenon in a montane tropical rainforest plot with an area of 60 hectares plot in Jianfengling of Hainan Province as the objectives of study, the quantitative characteristics of sprouting plants were analyzed and their spatial distribution characteristics were outlined. In this study, the sprouting plants were subdivided into two types:branches and sprouts. Result There are 260 species of woody plants with sprouting phenomenon, belonging to 58 families and 142 genera. The amount of families, genus and species of sprouting plants accounted for 93.5%, 91.6% and 89.7% of the total plants respectively.There are five species with the most sprouting stems, including Psychotria asiatica, Cryptocarya chinensis, Neolitsea ovatifolia, Lasianthus trichophlebus and Ardisia virens. Except Cryptocarya chinensis and Castanopsis jianfenglingensis, the effects of sprouting phenomenon on the changes of importance values were less than 0.05%. The sprouting phenomenon of plants was also significantly correlated with altitude with P-value < 0.001. Conclusion As the dominant regeneration type in the montane tropical rainforest in the plot, the sprouting stem contributes to the maintenance of biodiversity in the forest community and plays a major role for the species coexistence. It is suggested that the responses of the sprouting phenomenon after the typhoon disturbance should be further studied.
2019, 32(2): 25-31.
doi: 10.13275/j.cnki.lykxyj.2019.02.004
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Objective To understand the effects of nitrogen and sulfur deposition on the degradation of lignin during the litter decomposition in evergreen broad-leaved forest in subtropical area. Method A one-year field experiment of simulating nitrogen and sulfur deposition was conducted in the rainy area of west China. Three nitrogen and three sulfur levels resulting nine treatments were investigated, including the control (CK), low nitrogen (LN, 50 kg·hm-2·a-1), high nitrogen (HN, 150 kg·hm-2·a-1), low sulfur (LS, 200 kg·hm-2·a-1), high sulfur (HS, 400 kg·hm-2·a-1), low nitrogen and low sulfur deposition (LNLS), high nitrogen and low sulfur deposition (HSLS), low nitrogen and high sulfur deposition (LNHS), and high nitrogen and high sulfur deposition (HNHS). Result After one-year's simulation of nitrogen and sulfur deposition, the LN, LNLS and HNLS showed no significant effects on lignin remaining rate, the activity of polyphenol oxidase and catalase, while the LS treatment significantly reduced the lignin remaining rate and significantly enhanced the leaf litter C/N, cellulose loss rate, polyphenol oxidase and peroxidase activity. However, the HN, HS, LNHS and HNHS treatments improved significantly the lignin remaining rate, significantly decreased leaf litter C/N, cellulose loss rate, polyphenol oxidase and peroxidase activity. Furthermore, the simulated nitrogen and sulfur deposition interacted with each other, which affected the rate together. Conclusion The effects of nitrogen and sulfur deposition levels on lignin degradation and related enzymes are different during litter decomposition in evergreen broad-leaved forest in rainy area of west China. With the increase of atmospheric deposition, the lignin degradation of the evergreen broad-leaved forest has potentially been affected by nitrogen and sulfur deposition. The foliar litter decomposition process may be affected by atmospheric nitrogen and sulfur deposition in the forest.
2019, 32(2): 32-38.
doi: 10.13275/j.cnki.lykxyj.2019.02.005
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Objective To determine the best harvest period at the peak of nutrients and active ingredients and to provide solid basis for processing utilization of Camellia nitidissima by studying the dynamic patterns of three chemical components in 4 typical developmental stages of its petals. Method Total flavonoids and total polyphenols were determined by colorimetric method, dietary fiber by enzymatic method, ascorbic acid and soluble sugar by chromatography, amino acids by high performance ion exchange chromatography (HPIEC) with post-column derivatization, and mineral elements by atomic absorption spectrometry. Result The average content of total flavonoids, total polyphenols, total dietary fiber, soluble sugar, hydrolyzed amino acids and ascorbic acid in the petals of C. nitidissima at different developmental stages were 11.1%, 1.59%, 54.8%, 22.9%, 2.57% and 0.294 mg·g-1, respectively. Among the seven major elements tested, the main macro-elements were K (12.7 g·kg-1), Ca (2.97 g·kg-1), Mg (1.78 g·kg-1). Among the eight mineral trace elements detected, the main trace elements included Mn (188 mg·kg-1), Fe (38.4 mg·kg-1), Zn (5.93 mg·kg-1). Fe and Zn reached their peaks in early withering, while Se had the highest value in blooming period (0.048 9 mg·kg-1). The contents of bioactive components were ranked as below:full blossom > floral bud > half open > early withering. The rank of other nutrients were full blossom > early withering > half open > floral bud. Conclusion C. nitidissima petals are rich in the bioactive components and nutrients with good coordination in the full blossom, and are suitable for processing various kinds of functional food products.
2019, 32(2): 39-45.
doi: 10.13275/j.cnki.lykxyj.2019.02.006
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Objective To determine the azimuthal variation of the sap flow rate of trunks (Js) and estimate the effects of environmental factors on azimuthal variation. Method The sap flow rate of Pinus densiflora, an important windbreak and sand fixation species, was monitored continuously during the growing season using a thermal dissipation probe (TDP) method, combined with simultaneous observations of precipitation, soil moisture, and solar radiation and other environmental factors. Result The results of comprehensive analysis showed that the daily and seasonal changes of the Js in the four directions of the trunk basically followed the same pattern, and all were in accordance with the solar radiation. In moderate-intensity drought and extreme drought conditions, the Js of each direction was significantly suppressed simultaneously and quickly recovered after the soil moisture was fully replenished. On a typical sunny day, there were differences in the time at which the peaks of the Js appeared at various times. From early to later, it ranked with the order of the east, south, west, and north sides clockwisely. During the whole growing season, the daily mean value of Js was generally ranked of south > west > north > east, but the difference between directions was not significant (P=0.35). Statistics show that the average of the Js in the north side was the closest to the average of four azimuths (approximately 1.01 times the average). Conclusion The sap flow estimated through a measurement on the north side in the actual measurement will get better reliability in order to reduce the cost of observation. Meanwhile, the threshold value of soil moisture affecting the sap flow of Pinus densiflora is about 7.5%.
2019, 32(2): 46-52.
doi: 10.13275/j.cnki.lykxyj.2019.02.007
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Objective To determine the azimuthal character of sap flow velocity (Js) of apple trees. Method the thermal dissipation probe technology (TDP) was used to simultaneously and continuously monitor the sap flow velocity in the four locations of apple trees during the whole growing season in the loess region. The soil moisture and meteorological factors were measured simultaneously, too. Result The Js was significant different among directions (P < 0.01). The highest Js in the sapwood was observed in the north side with an average of 189.3 cm per day over the entire growing season, followed by that in the south side (83% of the north side) and the east side (80% of the north side). The Js from the west side was the smallest (63% of the north side). The Js of all sides showed seasonal dynamics, i.e. increasing in May-August, dropping in September-October, and nearly stopped in November. The Js showed an exponentially increasing relationship with the net radiation above canopy (Rn) as well as with vapor pressure deficit (VPD). On a typical sunny day, the diurnal peak time of Js in different directions appeared earlier than that of the VPD (1.6 hours in average with the maximum of 2.43 hours). The length of advancing time increased linearly with the increasing of the daily mean VPD. The time advancing reflects that the peak Js of apple was limited by VPD while over 2.0~2.2 kPa. The difference of time advancing between Js and VPD in four directions was not significant (P=0.97). Conclusion There are obvious azimuthal differences (P < 0.01) in the sap flow velocity of the apple tree. The Js in the north side and the south side are high than that of the east or the west side. However, the process of sap flow in different directions is consistent with the influence of atmospheric environment. In order to improve the accuracy of estimating sap flux of apple trees, the azimuthal difference should be taken into account in actual measurement.
2019, 32(2): 53-59.
doi: 10.13275/j.cnki.lykxyj.2019.02.008
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Objective The purpose of the study is to clarify the carrying rates and the differences of fungi associated with four Tomicus species in Yunnan, China and understand the relationships between the beetles and these fungi during Tomicus attacking process. Method Fungal carrying rate was analyzed by detecting stained phloem based on artificial inoculation and field survey. Result The fungal carrying rate of Tomicus yunnanensis (80%) was distinctly higher than that of the other three Tomicus species:T. minor (63%), T. armandii (56%), and T. brevipilosus (53%); the fungal carrying rate of Tomicus-larva (90%) was higher than its pupae (78%) and new adult (58%); No significant difference in fungal carrying rate was observed among heads (33%), wings (32%) and legs (30%) of Tomicus-adults. According to field survey, the associated fungi significantly improved the breeding success rate of Tomicus on the trunk. Conclusion This is the first report on the carrying rates and the differences of fungi associated with four Tomicus species in Yunnan, China. The results provide new data for reveal outbreak mechanism of Tomicus species in Yunnan, China.
2019, 32(2): 60-64.
doi: 10.13275/j.cnki.lykxyj.2019.02.009
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Objective The aim of the study is to determine the biological characteristics of Dioryctria abietella (Denis et Schiffermuller) on Picea likiangensis var. linzhiensis trees in Linzhi area, and provide a scientific basis for the control of this insect. Method From March 2015 to August 2016, the life history, morphological characteristics and habits of D. abietella were studied by field survey and laboratory observation. Result The results showed that the generation of D. abietella in Linzhi area occurred one generation a year. The larvae damaged the cone fruit shaft, seed scales and seeds of P. likiangensis var. linzhiensis, and the larvae overwintered in the cones, with the phenomenon diapause and no transfer hazard. The adult emergence started in the middle of June and continued until early August. The adult stage was 5 to 8 days, the egg stage was 9 to14 days, the larval stage was about 10.5 months and the pupal stage was 25~36 days. Conclusion D. abietella attacked the P. likiangensis var. linzhiensis cones and affected the natural regeneration of P. likiangensis var. linzhiensis forests. In order to reduce the population of D. abietella and the damage to P. likiangensis var. linzhiensis cones, it is suggested that the fallen cones and the malformation cones hanging on the tree should be cleaned and deeply buried in December and January each year.
2019, 32(2): 65-72.
doi: 10.13275/j.cnki.lykxyj.2019.02.010
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Objective To improve the accuracy of real-time fluorescence quantitative PCR test and provide a suitable background reference for expression analysis of Chinese fir (Cunninghamia lanceolata), so as to select the stable internal control genes. Method The soluble curve and Ct value of seven candidate internal reference genes including GAPDH, EF1α, 18S rRNA, 28S rRNA, UBQ, UBC and Actin in roots, stems and leaves of Chinese fir clones were obtained by real-time fluorescence quantitative PCR. The expression stability of candidate reference genes was assessed by geNorm, Normfinder and BestKeeper. The expression stability of candidate reference genes was estimated by analyzing the relative expression of two cellulose synthase genes ClCesA1 and ClCesA2 in different tissues of Chinese fir. Result Three softwares, geNorm, Normfinder and BestKeeper, showed that the most stable internal reference genes expressed in Chinese fir roots and stems were EF1α and Actin. The software geNorm and Normfinder showed that the stable internal reference genes expressed in Chinese fir leaves were UBQ and EF1α. The software BestKeeper showed that the most stable and suitable internal reference genes for expression analysis are EF1α and Actin. Actin and EF1α as internal reference genes showed that the relative expression levels of ClCesA1 and ClCesA2 were different among the tissues of Chinese fir, and the relative expression level of ClCesA2 was higher than that of ClCesA1 in all tissues. According to expression analysis of different reference genes as test reference gene expression of ClCesA1 and ClCesA2, the relative expression levels of ClCesA1 and ClCesA2 were mainly stem > leaf > root. Conclusion Of the 7 candidate reference genes, Actin and EF1α are suitable as internal control genes for expression analysis due to stably expressed in different tissues of Chinese fir. 28S rRNA is not suitable as an ideal internal control gene for quantitative PCR analysis of Chinese fir as a result of the lower expression stability.
2019, 32(2): 73-77.
doi: 10.13275/j.cnki.lykxyj.2019.02.011
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Objective To resolve the controversy over the phylogenetic position of Chosenia arbutifolia in Salicaceae. Method The whole chloroplast genome sequences of C. arbutifolia was determined by next-generation sequencing, and the phylogenetic position of C. arbutifolia was investigated by comparing its sequences with all available complete chloroplast genome sequences from the genera Populus and Salix. Result The total genome was 155, 661 bp, consisting of two single-copy regions separated by a pair of inverted repeats (IRs) of 27, 455 bp. The large single-copy (LSC) and small single-copy (SSC) regions spanned 84, 536 bp and 16, 215 bp, respectively. The total GC content of the chloroplast genome was 36.68% and 113 unique genes were annotated, including 79 protein coding genes, 30 tRNA genes, and four rRNA genes. Twenty genes were duplicated in the inverted repeat regions, 14 genes contained one intron, and three genes (rps12, clpP, and ycf3) contained two introns. Conclusion A phylogenetic tree constructed from all available complete chloroplast genome sequences from the genera Populus and Salix based on maximum likelihood, maximum parsimony and Bayesian inference strongly supports the merging of C. arbutifolia into the genus Salix. This study would supply an important basis for the genetic study as well as conservation of C. arbutifolia.
2019, 32(2): 78-86.
doi: 10.13275/j.cnki.lykxyj.2019.02.012
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Objective To study the effects of planting density on branch development and provide references for improving the wood quality of Mytilaria laosensis. Method The effect of planting density on branch development was examined in an eight-year-old M. laosensis plantation with five planting densities. The branch quantity (amount, proportion), morphology (diameter, length and angle of first-branch), position (height and orientation) and branch statues (dead or live) of 80 sample trees (5 033 branches) were investigated. Result The results showed that the dead branch layer increased with the increasing densities. No close relation was found between the amount of total branches or dead branches and the planting density, but the rate of dead branch increased with the increasing planting density. The basal diameter, length and angle of branch under 9 meters decreased with the increasing planting density. In the horizontal direction, the basal diameter, length, angle and amount of branch in same density and different orientation increased at first and then decreased with the increasing position angle. It reached the maximum value in a better illumination condition in the range of position angle (0-90° or 316-360°). In the vertical direction, the amount of branch increased gradually with the relative position and then closed to the uniform distribution. The basal diameter and length of branch correlated positively with the increasing height, and then less change was observed. The branch angle decreased from bottom to top in the vertical direction. Conclusion The diameter of branch is affected by planting density significantly. The branch growth is inhibited by high density (2500 tree·hm-2). It is suggested that the planting density should be chosen according to the cultivation aim, and pruning should be made as early as possible on the dominant or co-dominant trees, so as to improve effectively the wood quality.
2019, 32(2): 87-93.
doi: 10.13275/j.cnki.lykxyj.2019.02.013
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Objective To reveal the effects of different fertilization measures on soil fertility, and provide a reference for fertilization of old Torreya grandis. Method Three different fertilization treatments (non-fertilizer (CK), chemical fertilizer plus farmyard manure (CF+FM), and chemical fertilizer treatment (CF) were carried out in the Chinese Torreya National Forest Park in Zhuji, Zhejiang Province. Soil samples were collected from the field to analyze the total soil organic carbon (TOC), readily oxidizable carbon (ROC), light fraction organic matter (LFOM), and soil nutrient contents in 0-20, 20-40, and 40-60 cm soil layers. Result (1) Compared with the CK, the contents of TOC, ROC, LFOM, total nitrogen (TN), and available nitrogen (AN) in soil layers increased significantly under CF+FM treatment. The contents of ROC, LFOM and AN in the topsoil and the soil available potassium (AK) in each soil layer increased under CF treatment, especially AK. The effect of CF treatment on the increase of soil available phosphorus (AP) content was far less than that of CF+FM treatment. (2) Soil pH increased insignificantly under CF+FM treatment, while decreased significantly under CF treatment. (3) The ratios of ROC to TOC in three soil layer for different fertilization treatments showed:CF+FM > CF > CK, but only CF+FM treatment in surface soil was significantly higher than that of CK. (4) Correlation analysis showed that ROC, LFOM and TOC were extremely significantly correlated. The TOC, ROC and LFOM were significantly or extremely significantly correlated with TN, AN, AP, AK. Conclusion The organic-inorganic combination treatment is more conducive to the accumulation of soil organic carbon and soil nutrients than the single application of chemical fertilizer treatment.
2019, 32(2): 94-99.
doi: 10.13275/j.cnki.lykxyj.2019.02.014
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Objective To explore the potential hosts of Alternaria alternata, the pathogen of jujube shrunken-fruit disease (JSFD) and the sources of primary infection for JSFD. Method The spore suspension of a gfp-tagged strain of A. alternata CN193, designated as CN193::gfp, were inoculated with and without stab wound to the fruits and/or leaves of Lycopersivon esculentum, Nicotiana tabacum, Malus domestica cv. Red Fuji, Pyrus bretschneideri, Populus tomentosa and Populus canadensis from the surrounding area of jujube plantation. The marginal tissues with healthy and diseased parts were transferred onto potato dextrose agar media with supplement of 10 μg·mL-1 hygromycin B, and the infected tissues and the hyphae isolated from each of the inoculated material were observed under fluorescence microscope. Result All the inoculated materials with stabbing wound, except for N. tabacum plant, developed diseased symptoms after 7 days of inoculation. The disease rates of all the above materials inoculated with spore suspension were 45.8% of L. esculentum fruits, 79.2% of apple fruits, 75.0% of M. domestica cv. Red Fuji leaves, 56.3% of Pyrus bretschneideri fruits, 52.1% of Pyrus bretschneideri leaves, 66.7% of Populus tomentosa leaves and 54.2% of Populus canadensis leaves. Through non-wounded inoculation only L. esculentum fruits showed the symptoms, and all the other treated materials and the controls did not present any visible disease development. Strong fluorescence could be observed in the infected tissues of L. esculentum fruits, and in the hyphae of isolates from all infected materials, including the fruits of L. esculentum, the fruits and leaves of M. domestica cv. Red Fuji, the fruits and leaves of Pyrus bretschneideri, and the leaves of Populus tomentosa and Populus canadensis. Conclusion The pathogen of JSFD is able to successfully infect the L. esculentum, M. domestica cv. Red Fuji, Pyrus bretschneideri, Populus tomentosa and Populus canadensis, and it could cause the same symptoms as tomato melasma, apple brown spot, pear black spot, and poplar leaf blight, inferring that L. esculentum, M. domestica cv. Red Fuji, Pyrus bretschneideri, Populus tomentosa and Populus canadensis are the potential hosts of JSFD.
2019, 32(2): 100-110.
doi: 10.13275/j.cnki.lykxyj.2019.02.015
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Objective To reveal the genetic variation pattern of leaf morphological traits in poplar intersectional hybrid population, and to lay the foundation for studying their genetic mechanisms by analyzing the leaf morphological indexes in 422 F1 progenies from P. deltoides cl. 'Danhong'×P. simonii cl. 'Tongliao 1'. Method Seven indexes (leaf area, length, width, perimeter, petiole length, vein angle and the distance between largest width and blade tip) were measured through Yaxin-1241 portable area meter and manual measurement. Four indexes (the ratio of leaf length and width, relative length of petiole, position of the largest width and leaf margin factor) were calculated. Correlation, path coefficient, genetic and principal component analysis were accomplished by SPSS software. Result Significant differences were found between two parents for all morphology indexes except leaf margin factor. Plentiful phenotypic variations with normal and continuous distribution existed in hybrid population. As many as 36 of 45 pairs of correlations which were up to significant or extremely significant level. The result of path coefficient analysis indicated that the leaf area was determined mainly by leaf length and width. Two main factors were obtained through principal component analysis, which explained 80.19% of total variations. Standardized value of first principal component in progenies was fallen completely between two parents, with 64.69% were distributed on the same side of male parent, while the second principal component was evenly distributed on both sides of the median parents. Two indexes of leaf size (leaf area and petiole length) in progenies were lower than the median of parents, and the mean was closer to male parent. In contrast, the leaf shape indexes (relative length of petiole and the position of maximum blade width) were closer to the female parent. Other indexes were closer to the median of parents. Most indexes of leaf morphology were between two parents except the ratio of length and width, the leaf margin factor and the lateral vein angle. Conclusion There are significant differences in leaf morphological traits between two parents. The variation of leaf morphological traits in their progenies is continuous and plentiful, and these traits are closely associated, among which leaf length and leaf width are the main factors determining leaf area. Leaf area, petiole length and position of the largest width have a evident genetic bias, the leaf shape of hybrid offspring which is more similar to P. deltoides cl 'Danhong' poplar shows a strong maternal effect, while the leaf size shows a genetic bias toward the male P. simonii cl. 'Tongliao 1' parental effect. The comprehensive leaf shape index of 30.09% progenies has the transgressive segregation phenomenon, which has great potential for selection, and could be utilized in tree breeding in the future.
2019, 32(2): 111-116.
doi: 10.13275/j.cnki.lykxyj.2019.02.016
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Objective To analyze the relationships among deadwood symptom grades, the salicylic acid content and the DBH of Malus sieversii trees collected in same sampling site and habitat conditions was analyzed in order to find the features of M. sieversii that might be related to the symptoms of exsiccation. Method The difference in salicylic acid composition and content in different symptom grades of M. sieversii was investigated by ultrasonic extraction and HPLC methods. Statistical analysis was conducted to find the relationships among deadwood symptom grades, the salicylic acid content and DBH of M. Sieversii. Result The content of salicylic acid in M. sieversii branches and leaves with different deadwood symptom grades was in the range of 39.5~122.6 mg·kg-1, showing significant difference (P < 0.05). Along with deadwood symptoms from grade 0 to grade Ⅴ, the salicylic acid content fell down at first and then up. The variation coefficient of DBH size of M. sieversii was significantly different. The variation coefficient of DBH among grade Ⅴ samples was relatively high (39.18%), and the coefficient of grade Ⅰ samples was comparatively low (30.28%). There was a negative correlation between salicylic acid content and DBH of M. sieversii (P>0.05). There was a positive correlation between salicylic acid content and DBH of grade 0 and grade Ⅴ samples, and there was a negative correlation between salicylic acid content and DBH of samples of grades Ⅰ, Ⅱ, Ⅲ and Ⅳ (P>0.05). Conclusion There is a comparatively close relationship among deadwood symptom grades, the salicylic acid content and the DBH of M. sieversii. The results achieved in the study will provide some reference clues for ecological conservation and restoration of wild fruit forest in Tianshan Mountains and the screening and cultivation of high-quality varieties of cultivated apple.
2019, 32(2): 117-122.
doi: 10.13275/j.cnki.lykxyj.2019.02.017
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Objective This study aims to identify the pathogen of apricot fruit spots disease in Gongliu County, Xinjiang, and to find the causes of apricot fruit diseases, so as to provide a reference for the disease prevention and control of local apricot trees. Method The fungal strains on the infected apricot were isolated by using conventional tissue separation method, and the isolates were identified by morphological observation, phylogenetic analysis and pathogenicity. Result The morphological feature of conidia developed on apricot fruit lesions and PDA medium were consistent with the conidia produced by Thyrostroma carpophilum (Lév.) B. Sutton. Furthermore, sequence identity comparison showed that all the three strains obtained were 100% identical in rDNA-ITS sequences with the NCBI reference sequence of T. carpophilum, and the three strains grouped into one consensual cluster with the reference isolates of T. carpophilum in the phylogenic tree based on rDNA ITS sequence. After inoculation of the obtained isolate, both apricot fruits and leaves produced obvious lesions, and the pathogen were again isolated from the lesions, thereby satisfying Koch's postulate. Conclusion The three strains isolated from the apricot fruit spots in Gongliu County were identified as T. carpophilum. This is the first report of this disease presence in Xinjiang Uygur Autonomous Region.
2019, 32(2): 123-130.
doi: 10.13275/j.cnki.lykxyj.2019.02.018
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Objective The study aims at revealing the morphological characteristics and histological structure during aseptic seed germination of Calanthe tsoongiana, so as to provide some references for its conservation and in vitro rapid propagation. Method This study was conducted by using wild population of C. tsoongiana distributed in Tianmushan, Zhejiang Province, aseptic germination was taken after harvesting the fruits. The process from seed germination to initial seedling formation was studied and divided into several developmental stages by morphological observation and paraffin section method. Result It proved that the Vacin & Went (VW) medium was the suitable basal medium for seed germination which was facilitated by coconut water. Nevertheless, the banana slurry had an inhibitory effect. The germination rate reached the highest when harvesting the fruit at the time of four months or so after pollination. The process of seed germination was divided into four stages according to the observation on swelled embryo, the presence and development of shoot apical meristem, the differentiation of young leaf and root, etc. Conclusion The process of aseptic seed germination is mainly composed of two biological processes, seed imbibition and the form and differentiation of protocorm. Apical meristem, chloroplast and vascular bundle are the major structures during the growth and development of protocorm.
2019, 32(2): 131-138.
doi: 10.13275/j.cnki.lykxyj.2019.02.019
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Objective To study the effect of N, P, K fertilization ratios on the flower bud differentiation of Camellia oleifera for the purpose of getting the optimum fertilization proportion and providing a reference for the efficient cultivation of C. oleifera. Method The test material was 8-year-old C. oleifera 'Changlin-4'. Orthogonal design L9(34) with 3 factors and 3 levels fertilization experiment was carried out. Result Within the test fertilizer levels, the results showed that adding N and K fertilizers to the soil significantly improved the rate of flower differentiation of C. oleifera; and the optimum N, P, K fertilization proportion was N222.22P81.83K240.24. In the physiological differentiation stage of C. oleifera flower bud, fertilization could promote the flower bud differentiation by increasing ABA content, while the ABA content had a moderate positive correlation with flower bud differentiation rate, and the correlation was significant. The correlation between endogenous hormones (ZR, IAA, GA3) and flower bud differentiation was not significant. In the flower bud morphological differentiation period, the application of N and K increased the flower bud contents of ZR, IAA and GA3, decreased the ABA content of flower bud. And it promoted the flower bud morphogenesis of C. oleifera. Conclusion The appropriate ratio of NPK fertilization could promote flower bud differentiation and increase the rate of flower bud differentiation by affecting the level of endogenous hormones related to flower bud differentiation of C. oleifera.
2019, 32(2): 139-144.
doi: 10.13275/j.cnki.lykxyj.2019.02.020
Abstract:
Objective To investigate the effect of salicylicacid (SA) on seed germination, seedling morphological and physiological index of Platycladus orientalis and to select the best concentration of SA. Method Soaking application of SA was used to process P. orientalis seed with 5 concentrations (0.5, 1.0, 1.5, 2.0 and 3.0 mmol·L-1), and the seeds soaked in distilled water as a control. The seed germination index, morphological index, antioxidant enzyme activity and the content of MDA were measured in the end of germination. Result SA soaking significantly improved the germination rate and germination index of P. orientalis, 1.5 mmol·L-1 treatment manifested the highest rate of 96.3%, which was 9.3% higher than that of the control. The highest germination index was 3.0 mmol·L-1, which was 26.5% higher than that of the control. Low concentration SA (≤ 1.0 mmol·L-1) promoted the seedling growth of aerial part and inhibited the underground part. High concentration SA (≥ 1.5 mmol·L-1) inhibited the seedling growth of aerial part and promoted the underground part. The activity of SOD was the highest in 1.5 mmol·L-1 SA, which increased by 69.0%. The CAT activity with 1.5 mmol·L-1, 2.0 mmol·L-1 and 3.0 mmol·L-1 were higher than that of the control, which increased by 33.9%, 10.7% and 19.9%. The MDA content decreased gradually, but the difference was not significant among treatments. It is possible that SA could improve the activities of antioxidant enzymes and reduce the membrane lipids. Besides, the seeds themselves were in good quality, and the external environment was not related to stress. Conclusion 1.5-3.0 mmol·L-1 SA was better to increase the germination rate, SOD and CAT activities of seedlings, improve the seedling growth of underground part. And there was no significant difference among treatments. For reducing the production costs, 1.5 mmol·L-1 SA is considered in applications.
2019, 32(2): 145-151.
doi: 10.13275/j.cnki.lykxyj.2019.02.021
Abstract:
Objective To reveal and compare the contents of crude protein, flavonoids, nitrates and their antioxidant activity of Toona sinensis harvested in different time, and to find the optimal harvest time for fodder utilize. Method The contents of crude protein, flavonoids and total nitrates of rachises of T. sinensis harvested from May to November were analyzed, and their antioxidant activity were determined by ORAC, DPPH and FRAP. Combining the nutritional and healthy analysis, the optimal harvest time was determined. Result There were significant differences in the crude protein, flavonoids, total nitrates contents and antioxidant activity of T. sinensis harvested in different time(P < 0.05). The crude protein content (varied from 13.17% to 22.65%) presented a downward trend with the maturity of T. sinensis. But except the samples harvested after mid-October, the rest samples showed protein forage advantage with the crude protein contents higher than 15%, which were far higher than the conventional grain feedstuffs. The flavonoids content of T. sinensis harvested at any time were highlighted (15.87 mg·g-1 in average), which was far higher than that of the common fruits and vegetables, such as blueberries, and was persistently accumulated with the maturity of rachises, and reached the highest in October (27.02 mg·g-1). The results of ORAC, DPPH and FRAP assay all showed outstanding antioxidant activities which increased with the maturity of rachises. Meanwhile, very significant positive correlations (P < 0.01) were detected between the flavonoids content and the antioxidant activities. A large amount of nitrates was detected in T. sinensis from different harvest time (2 306.39~7 346.80 mg·kg-1). The accumulation of nitrates in T. sinensis followed a V-shape along with its maturity. The T. sinensis harvested in the mid-July and August, with the average nitrates content of 2 603.78 mg·kg-1, contained the lowest nitrates content. Conclusion The feeding quality of T. sinensis harvested in different time is proved to be significantly different. Comprehensively considering the nutritional value and health care effect of T. sinensis, the mid-July and August are the optimum harvesting time for the forage development of T. sinensis.
2019, 32(2): 152-159.
doi: 10.13275/j.cnki.lykxyj.2019.02.022
Abstract:
Objective To study the effects of seed moisture content and storage temperature on the physiological and biochemical characteristics of Toona sinensis by analyzing the germination index and antioxidant enzyme activity, so as to provide references for the storage method of T. sinensis seed. Method The seeds of Toona sinensis with five water contents of 9.1%, 12.2%, 14.0%, 15.8% and 17.8% were obtained under 100% humidity environment and stored for 90 days at 10℃, 15℃ and 20℃. The seed germination rate and antioxidant enzyme activity were measured every 30 days. Result Under the same storage conditions, the seed germination percentage, vigor index, CAT activity and POD activity decreased gradually with the increase of storage time, and the SOD activity increased at first and then decreased, the conductivity and the content of MDA went up gradually. After 90 days of storage, with the increase of water content or temperature, the seed germination percentage and vigor index of T. sinensis decreased, the conductivity and MDA content of the extract increased significantly. The activities of SOD, POD and CAT decreased significantly with the deepening of aging. Conclusion Both conductivity and MDA content indexes are significantly and negatively correlated with germination percentage. Antioxidant enzyme activity is significantly and positively correlated with germination percentage. Membrane lipid peroxidation is one of the important reasons for aging deterioration of T. sinensis seed. The safe storage conditions of T. sinensis seed in this experiment are as follows:when the temperature does not exceed 15℃, the water content should be controlled below 12.2%; when the temperature is between 15℃ and 20℃, the water content should be below 9.1%.
2019, 32(2): 160-165.
doi: 10.13275/j.cnki.lykxyj.2019.02.023
Abstract:
Objective To study the optimal in vitro culture conditions of Toona sinensis pollen, the correlation between pollen germination rate and anther size and water content, and the variation of pollen vigor in different low temperature storage time. Method The pollens from three T.sinensis genotype plants(XC5, XC22, ZJ26) were used as experimental materials to observe the germination rate of pollen in vitro under different culture temperatures(20, 22, 25, and 28℃) and different culture times(4, 6, 12, 18, 30, and 42 hours), in order to obtain the optimal culture conditions.The anther water content, length and width of each genotype were measured. And the relationship between pollen germination and anther water content, length and width was analyzed. The germination on the optimal culture condition of T. sinensis pollen at low temperature (-20℃) for 10, 25 and 40 days were viewed. And the change trend of pollen vigor with low temperature storage time was analyzed. Result The germination rate of T. sinensis pollen at 20℃ was significantly higher than that at the other culture temperatures. The pollen germination rate increased with the increase of culture time. After 30 hours, the pollen germination rate did not increase obviously.There was dramatically positive/negative correlation between pollen germination rate and anther length/width, and the R2 were 0.529 6 and -0.739 9, respectively, while the pollen germination rate was not significant positive correlated with the anther water content at low temperature for 10 days. With the extension of low temperature storage time, the pollen germination rate decreased greatly. The pollen germination rates of the XC22, a high water content genotype, in low temperature storage for 10 and 25 days were 89.2%, 3.3%, respectively. Conclusion The optimal in vitro culture condition for the pollen vigor of T. sinensis was 20℃ for 30 hours. The correlation between the germination rate of T. sinensis pollen and the size, water content of anther might be used as indicators for screening pollen vigor. Low temperature storage might have a greater influence on the pollen vigor of T. sinensis with high water content.
2019, 32(2): 166-173.
doi: 10.13275/j.cnki.lykxyj.2019.02.024
Abstract:
Objective To construct the core collection bank of Tetracentron sinense. Method Taking 161 germplasm of T. sinense as samples, the genetic variation data of leaf phenotypic characters of T. sinense were studied. First, the methods of Euclidean distance and Wald were used to cluster all individuals step by step. Second, 10 sampling ratios (10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, and 55%) were set, and then their core collection were screened by random sampling strategy, deviation sampling strategy and allele preferred sampling strategy. The germplasm resource banks constructed under different sampling strategies were compared and then the optimum core collection was screened out. Result (1) Among the three sampling strategies, the allele preferred sampling strategy significantly increased the percentage of variance difference (VD), the variation rate of coefficient of variation(VR) and the coincidence rate of range difference (CR) in core collection. 45% is the most suitable sampling ratio to construct core collection of T. sinense. (2) The t test for different quantitative characters of core collection showed that the cumulative contribution rate of core collection was higher than 82%. Conclusion The allele preferred sampling strategy is the most appropriate to construct the core collection of T. sinense with the methods of Euclidean distance and Wald.
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