干旱胁迫对不同种源香椿苗木生长的影响

Effects of Drought Stress on Seedling Growth of Toona sinensis from Different Provenances

以南京、广元、洞口、随州、西峡、安康6个种源香椿苗木为材料进行盆栽试验,研究干旱胁迫对香椿苗木生长的影响。结果表明:干旱胁迫显著抑制香椿苗木相对高生长和相对地径生长,随着胁迫程度的加重生长下降幅度加大。洞口种源在轻度和重度干旱胁迫下相对高生长皆最小,且下降幅度最大,表现出较弱的抗旱性。安康种源轻度胁迫水平下相对高生长上升,重度胁迫下下降,说明在重度胁迫下安康种源苗高生长受到了一定的抑制,但下降幅度是最小的;西峡种源在轻度胁迫水平下相对地径生长增加,重度干旱胁迫下下降幅度最小,其地径生长受到的抑制最小,表现出较强的抗旱适应性。干旱胁迫处理对不同种源香椿生物量增量和根冠比产生极显著影响。不同种源香椿生物量增量随着胁迫程度的加重而大幅减小,根冠比增加。综合不同干旱胁迫水平对各种源苗木生长的影响认为,西峡和安康种源抗旱性较强,洞口种源相对较弱。

The effects of drought stress on seedling growth from six Toona sinensis provenances （Nanjing, Guangyuan, Dongkou, Suizhou, Xixia and Ankang） grown in pots were investigated. The results showed that the relative height and the relative ground diameter of Toona sinensis seedlings were significantly decreased with the intensity of the drought stress. The relative height growth of Dongkou provenance was the smallest under both light and heavy drought stress, indicated a weaker resistance to drought. The relative height growth of Ankang provenance was increased under light drought stress, while decreased under heavy drought stress. But the decreased degree was the smallest under heavy drought stress. For Xixia provenance, the relative ground diameter was increased under light drought stress while slightly decreased under heavy drought stress, indicated a stronger resistance to drought. The biomass for all provenances studied was significantly decreased with the drought stress, while the roots/shoots ratio increased.