干旱对构树幼苗生理代谢及抗性系统影响的性别差异
Gender Differences in Physiological Metabolism and Resistance System of Broussonetia Papyrifera Seedlings under Drought Stress

为研究构树幼苗对干旱胁迫生理响应的性别差异，以扦插雌雄幼苗为材料，设轻、中、重度干旱和水分充足4个水分梯度，分别处理48 d后，测定光合指标、代谢指标、抗性指标及受伤害指标，分析干旱对构树幼苗生理代谢及抗性系统影响的性别差异。结果表明：1) 轻、中度干旱提高了雌雄幼苗的Pn、Gs和Ci，重度干旱抑制了现实Pn和潜在Pn，4个水分下，雄株的Pn、Gs、Tr、Ci均大于雌株(P < 0.05)，潜在Pn小于雌株，干旱下雄株光合能力大于雌株；2) 轻度干旱提高了雌雄幼苗的SS、ST和SU含量，中干旱增加了NR活性，随干旱度增加PA含量增加，4个水分下，雄株的SS、ST、SU含量及NR活性均大于雌株(P < 0.05)，PA含量小于雌株，干旱下雌株呼吸作用大于雄株；3) 随干旱度增加雌雄幼苗的SOD、POD和CAT活性显著提高，4个水分下，雌株抗氧化酶活性均大于雄株(P < 0.05)，干旱下雌株抗旱投入大于雄株；4) 随干旱度增加雌雄幼苗的MDA和SP含量增大(P < 0.05)，4个水分下，雌株MDA和SP含量均高于雄株(P < 0.05)，雌株更易受到干旱胁迫在伤害。综上，雄株对干旱胁迫敏感且生理响应快于雌株，雌株抗旱投入大于雄株。抗旱生理性别差异随干旱度增加而缩小，雌株潜在光合速率和抗旱潜力大于雄株。轻度干旱利于构树幼苗生长发育。
In order to study the gender difference of physiological response of Broussonetia papyrifera seedlings to drought stress, four water gradients, mild, moderate and severe drought and water sufficiency (CK), were set up. After treatment of male and female seedlings 48 days respectively, photosynthetic index, metabolic index, resistance index and injury index were measured to ana-lyze the gender difference of drought on physiological metabolism and resistance system of B. papyrifera seedlings. The results showed that: 1) Mild and moderate drought increased Pn, Gs and Ci, while severe drought inhibited Pn and potential Pn of male and female seedlings. Under four water conditions, Pn, Gs, Tr and Ci of males were higher than females (P < 0.05), while Pn was lower than females, so photosynthetic capacity of males was higher than females; 2) mild drought increased SS, ST and Su contents of male and female seedlings, while medium drought increased NR activity, but PA content increased with drought degree. The SS, ST, SU contents and NR activities of males were higher than females (P < 0.05), and PA content was lower than females under 4 water conditions, indicating that the respiration of females was higher than males under drought; 3) The activities of SOD, POD and CAT of male and female seedlings were increased with drought degree significantly. The activities of antioxidant enzymes of females were higher than males under 4 water conditions (P < 0.05), so drought resistance input of females was higher than males; 4) with drought degree increasing, MDA and SP contents of male and female seedlings were increased (P < 0.05). Under 4 water conditions, MDA and SP contents of females were higher than males (P < 0.05), which showed that the females were more vulnerable to drought than males. In conclusion, males were sensitive to drought stress and physiological response faster than females, but females were more input to resistant drought than males. The gender