土壤水分胁迫对冬小麦叶片渗透调节及叶绿体超微结构的影响

土壤水分胁迫下 ,抗旱性强的小麦品种昌乐 5号、北农 2号与抗旱性弱的济南 13、鲁麦 5号相比 ,渗透调节能力高 0 4 1～ 0 60MPa ,相对含水量少降 6 39～ 10 74个百分点 ,叶水势少降 0 19～ 0 63MPa。水分胁迫使小麦叶片光合能力下降 ,水分胁迫全过程下降平均百分数 ,抗旱性强的品种比抗旱性弱的品种光合速率少降 17 7%～ 2 2 5% ;气孔导度少降 2 1 0 6%～2 3 75%。小麦叶肉细胞叶绿体的超微结构发生变化且随水分胁迫的加重而加剧 ,但变化程度与小麦的抗旱性及渗透调节能力成负相关。胁迫导致叶绿体外形变圆 ,类囊体肿胀 ,片层间距加大 ,基质片层模糊 ,最终叶绿体解体

Effects of Soil Water Stress on Osmotic Adjustment and Chloroplast Ultrastructure of Winter Wheat Leaves

Under soil water stress,osmotic adjustment ability of wheat cultivars with strong drought resistant was 0 41MPa-0 60MPa stronger than that of wheat cultivars with weak drought resistant.Dropping percentage of rilative water content and dropping value of water potential were 6 39-10 74 percentage point and 0 19MPa-0 63MPa less than that of weak drought resistant cultivars.Meanwhile,Photosynthetic capacity was inhibited under soil water stress.However,the degree of inhibition of photosynthetic rate and stomatal conductance of strong drought resistant cultivars were 17 7%-22 5% and 21 06%-23 75% less than that of weak drought resistant cultivars,respectively.Ultrastructure changes of wheat mesophyll cell chloroplast of 2 cultivars were examined under soil water stress.The more severe the soil water stress was,the greater the changes of chloroplast ultrastructure were.The changes were negative correlation with cultivars'drought resistant and osmotic adjustment ability.The morphology of chloroplast under soil water stress changed into circlar.Thylakoid of chloroplast became swollen,matrix lamella became obscure,ultimately,the chloroplast were disintegrated.