Studies On The Accumulations Of Osmotic Adjusting Substances In The Seedlings Of Pinus Massoniana L. And Their Relationships With Drought-resistance

Accumulations of osmotic adjusting substances and their relationships with drought-resistances of mason pine (Pinus massoniana L.) seedlings were studied. And drought-resistances of the masson pine seedlings from different provenances were comprehensively evaluated by using morphological and physiological indexes. The results were shown as follows:1. The pinitol content in the needles of one-year masson pine seedlings increased along with seedling growth, and reached the highest point in hardening phase. However, the pinitol content in the needles of two-year masson pine seedlings decreased along with seedling growth and only increased in hardening phase. The changes of the contents of myo-inositol, galactose and maltose were relatively complicated. The glucose content changed steadily, and the glucose content in the needles of two-year seedlings was much higher than that in the needles of one-year seedlings in August.2. The contents of both pinitol and myo-inositol were the highest in stems, the second in roots and the lowest in needles in both one-year and two-year masson pine seedlings. But the pinitol content was much higher than myo-inositol content in all three kinds of organs. The glucose content was in a high level in stems and needles, and it was in a low level in roots. The contents of both galactose and maltose in stems were higher than those in needles. The maltose was not detected in roots.3. The accumulations of pinitol, glucose and proline were closely related to the drought-resistance of masson pine seedlings. The contents of above osmotic adjusting substances increased along with the aggravation and the prolongation of drought stress. However, there were no obvious relationships between the accumulations of myo-inositol, galactose, maltose as well as free amino acids and the drought resistances of masson pine seedlings. The contents of these osmotic adjusting substances had trends of increasing after drought stress, but their trends of increasing were not obvious as the stress prolonged.4. The morphological and physiological indexes of masson pine seedlings from different provenances were significantly affected by water stress. According to a comprehensive evaluation by means of subjective fuctions in which the morphological and physiological indexes of mason pine seedlings were used, the range of provenances in the degree of drought-resistance of masson pine seedlings from strong to weak was: Rucheng Hunan > Xinyi Guangdong > Dawu Hubei > Jiangshan Zhejiang > Qianjiang Chongqi.