The leaf nutrient, biomass and carbon reserve of 9-year-old Populus×euramericana cv. ‘74/76’ stump grafting stand with 26-year-old P.×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’as rootstock, 26-year-old P.×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’ and 9-year-old P.×euramericana cv. ‘74/76’ planting stands were compared. The result showed that the average increment and the annual average increment of stump grafting stand were greater than the two planting stands. The total nitrogen content in leaves of stump grafting stand was the highest, and it was 1.26 times and 1.05 times as much as that of the planting stands of Populus×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’ and P.×euramericana cv. ‘74/76’ separately. The total phosphorus content of stump grafting stand was 1.3 times as much as that of planting stand of 26-year-old P.×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’, but there was little difference between stump graftin stand and planting stand of 9-year-old P.×euramericana cv. ‘74/76’. The total potassium of stump grafting stand was 46.6% and 95.8% lesser than that of the planting stands of P.×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’ and P.×euramericana cv. ‘74/76’. The biomass of aerial parts and the biomasses of trunk, branches and leaves of stump grafting stand were 1.84, 1.80, 1.76, and 3.00 times as much as that of planting stand of P.×euramericana cv. ‘74/76’ separately. The total root biomass of the stump grafting stand was 1.42 times and 7.68 times as much as that of planting stands of 26-year-old P.×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’ and 9-year-old P.×euramericana cv. ‘74/76’. There was an obvious advantage in carbon reserve from all the parts of the stump grafting stand and the carbon sequestration capacity was the highest, which was 2.66 times and 1.62 times as much as that of planting stands of 26-year-old P.×xiaozhuanica W.Y.Hsu et Liang cv.‘Popularis’ and 9-year-old P.×euramericana cv. ‘74/76’. These showed that the stump grafting stand had more advantages than planting stands.

目的 以北方干旱区常用的3种松科植物沙地赤松、樟子松和青海云杉为研究对象，分析其种子萌发特性及对干旱胁迫的响应。沙地赤松为辽宁省固沙研究所于2014年筛选审定的新品种，目前在辽宁省生长状况良好，尚未有过其抗旱能力的相关研究。青海共和是高寒沙区，将沙地赤松与青海省常见的两种松科植物青海云杉和樟子松进行对比，以期为沙地赤松在青海引种试种提供参考。 方法 采用不同浓度PEG-6000溶液模拟干旱胁迫的方法进行种子萌发试验，利用模糊隶属函数对干旱胁迫下3种松科植物的种子相对发芽率、相对胚根长、相对胚芽长、萌发胁迫指数、萌发抗旱指数和萌发活力指数等6项指标进行综合评价。 结果 低浓度的PEG-6000溶液对3种松科植物种子萌发和胚根生长发育均有促进作用；随着干旱胁迫程度的加剧，3种松科植物的发芽率、幼苗鲜质量、活力指数、萌发胁迫指数、萌发抗旱指数均呈先上升后下降的趋势；种子萌发期耐水分胁迫能力为沙地赤松>樟子松>青海云杉。 结论 沙地赤松比樟子松和青海云杉的抗旱性强，适宜在青海引种试种。

用L i-6400便携式光合仪,于2004年6—9月测定了毛乌素沙地紫穗槐的光合速率与蒸腾速率,研究了光合速率和蒸腾速率日变化特征及环境因子对其的影响,结果表明:光合速率日变化在6、7月呈双峰型,峰值分别出现在8:00和18:00时,在8、9月呈单峰型,最大值出现在12:00时;蒸腾速率日变化在6、7月呈双峰型,6月峰值分别出现在10:00和18:00时,7月峰值分别出现在10:00和16:00时,低谷都出现在14:00时,在8、9月呈单峰型,峰值出现在12:00时;8月是光合速率和蒸腾速率最大的月份,分别为15.48μmol.m-2.s-1、5.87 mmol.m-2.s-1。在土壤含水量和光强适宜的情况下,空气湿度对紫穗槐光合速率和蒸腾速率的影响大于温度;在6—9月,紫穗槐的水分利用效率呈现波动,表明其光合速率、蒸腾速率受环境影响较大。

在晋西黄土区，研究了荒草地、锦鸡儿灌木林地和刺槐乔木林地3种典型植被不同土层的土壤密度、含水量、贮水能力和入渗性能的差异及其相关性，结果显示：3种植被类型都能有效减小表层（0~20 cm）土壤密度； 3种植被类型表层（0~20 cm）的土壤滞留贮水量较大，锦鸡儿林地（198.80 t·m-3）>刺槐林地（166.10 t·m-3）>荒草地（87.37 t·m-3），20~40 cm土层的土壤滞留贮水量也是锦鸡儿林地（127.30 t·m-3）>刺槐林地（55.60 t·m-3）>荒草地（47.30 t·m-3），表明在3种植被类型中，锦鸡儿林地对晋西黄土丘陵区土壤水分的涵养作用最强；锦鸡儿林地的土壤稳渗速率最大，为1.80 mm·min-1，刺槐林地次之，为1.46 mm·min-1，荒草地依然最小，且锦鸡儿林地土壤的均渗速率最大，为4.81 mm·min-1，其次是刺槐林地，为4.51 mm·min-1，荒草地最小。土壤密度与滞留贮水量呈极显著负相关关系，与土壤初渗速率和均渗速率呈极显著负相关关系，与稳渗速率呈显著负相关关系，非毛管孔隙度与稳渗速率和均渗速率存在极显著相关关系。 Kostiakov模型和Horton模型对晋西黄土区3种植被类型土壤入渗过程模拟的拟合系数高达0.97和0.95，明显优于Philip模型（0.43）。