杨树无性系幼苗光合作用和PV水分参数对水分胁迫的响应

RESPONSES OF PHOTOSYNTHESIS AND PV-PARAMETERS TO WATER STRESS IN POPLAR CLONE SEEDLINGS

比较研究了不同水分条件下杨树 2个无性系幼苗的生长、光合特性和多种水分参数等 ,探讨其对水分胁迫的适应机制。结果表明 ,水分胁迫下 2个无性系幼苗的生长减慢 ,净光合速率降低 ,昭林杨 6号受水分胁迫影响较小 ,欧美杨 6 4号受水分胁迫影响较大。胁迫初期 ,2个无性系光合作用受气孔限制 ,胁迫后期及复水后的恢复期 ,光合作用受非气孔限制。胁迫时杨树呼吸速率降低 ,尤其是昭林杨 6号 ,以保持碳平衡。胁迫时 2个无性系的 ψs1 0 0 、ψs0 、ROWC0 均降低 ,ψs1 0 0 与 ψs0 差值增大 ,表明杨树可以通过渗透调节维持压力势 ,对水分胁迫作出适应性反应 ,与欧美杨 6 4号相比昭林杨 6号这种能力更强 ,表明其抗旱性强。

Growth, photosynthetic characteristics and water parameters of two Poplar clone seedlings were studied comparatively under different water conditions in order to explore their adaptation mechanism to water stress. The results indicated that water stress affected growth and photosynthetic rate of the 2 Poplar clones, and its effect on Populus×xiaozhuanica ‘Zhaolin 6’was less than on Populus×euramericana cv.‘N3016’.Photosynthesis of the 2 clones was limited by stomatal factor within 16 days after water stress;and it was limited by non stomatal factor 16 days after stopping watering and in the recovering period.Respiration rates decreased under water stress conditions,especially that of ‘Zhaolin 6’,which was advantageous to carbon balance. When water stress was imposed , ψ s 100 , ψ s 0 and ROWC 0 of the two clones decreased,and the difference between ψ s 100 and ψ s 0 increased ,which showed that Poplar could have adaptation reaction to water stress through osmotic adjustment and maintain turgor. And the ability of Populus×xiaozhuanica ‘Zhaolin 6' was stronger than that of P.×euramericana cv.‘N3016’, which indicated that drought tolerance of Populus×xiaozhuanica ‘Zhaolin 6' was greater.