Shoot Growth Behavior of Superior Masson Pine Provenances under Different Phosphorus Environment

The behaviors and mechanisms of shoot growth of superior masson pine provenances were studied to explain height growth response of various provenances to different phosphorus supply. Growth cycles of different provenances were found to be not related to phosphorus environment. The sensitivities of annual shoot growth to phosphorus supply varied with provenances tested. This difference of sensitivity could be explained by changes of fixed growth and free growth. Genetic analysis connected to phosphorus environment indicated that the differences between provenances increased in shoot length and free growth, decreased in fixed growth and did not change in growth, cycles with amelioration of phosphorus environment. It is found that the phosphorus environment influenced not only genetic variation but also genetic correlation among shoot traits. Under low phosphorus or phosphorus stress, shoot length was significantly and negatively related to fixed growth, and positively related to free growth. After phosphorus supplying, the shoot length seems to be only related to free growth.