水分胁迫对土沉香生理生化特性及根系形态的影响

采用盆栽控制土壤水分法进行试验，分析了水分胁迫对1年生土沉香幼苗游离脯氨酸含量、光合特性以及根系形态参数的影响。结果表明，随着土壤含水量的减少，土沉香幼苗叶片脯氨酸含量显著上升，净光合速率Pn、蒸腾速率Tr和气孔导度Gs均下降，胞间CO2浓度Ci先降后升。在轻度水分胁迫（ W1）条件下Pn降低是由气孔限制引起，而在中度水分胁迫（W2）和重度水分胁迫（W3）条件下Pn降低是由非气孔因素引起。水分胁迫条件下，土沉香幼苗总根长、总根表面积、平均根系直径、总根体积、根尖数和根分支数等根系参数均降低，说明土沉香幼苗的耐旱能力有限。

Effect of Water Stress on Physiological Characters and Root Morphology of Aquilaria sinensis Seedlings

The effects of water stress on free praline content , photosynthesis character and root morphology of Aq-uilaria sinensis seedlings were studied .The pot experiment was carried out by using soil water controlling method . The results showed：with the decrease of soil water content , the proline content increased significantly , while net photosynthesis （Pn）, transpiration （Tr）, and stomatal conductance （Gs） all decreased, and the internal CO2 （Ci） decreased first and then increased.Under mild water stress （W1）, the decrease of Pn was mainly caused by stomatal limitation, while under moderate water stress （W2） and severe water stress （W3）, the decrease of Pn was due to non-stomatal factors .Under water stress conditions , root morphological parameters including total length , to-tal surface area , average root diameter , total root volume and root tip number all decreased , which illustrated that drought-resistance ability of A.sinensis seedlings was limited .