不同种源马尾松幼苗对水分胁迫的生理响应

为了探索不同种源马尾松Pinus massoniana幼苗对水分胁迫的生理响应，用不同质量浓度聚乙二醇（PEG6000）对广东信宜、浙江淳安和贵州都匀等3个种源的马尾松幼苗进行人工水分胁迫处理。结果表明，水分胁迫下，各种源叶绿素质量分数都有所下降，PEG质量浓度为250g·L^-1时，广东信宜与浙江淳安2个种源分别下降了17．51％和17．69％，而贵州都匀种源则下降了14．98％。PEG质量浓度为350g·L^-1时，广东信宜、浙江淳安种源下降幅度为25．70％和27．27％，贵州都匀种源则为18．21％。质膜相对透性随着水分胁迫的加剧呈上升趋势，PEG质量浓度为250～350g·L^-1时上升幅度明显加大。过氧化物酶（POD）活性呈先上升后下降的趋势，在300g·L^-1 PEG处理下，广东信宜种源POD活性下降幅度达43．90％，浙江淳安和贵州都匀种源下降幅度较小，分别为23．99％和27．06％。随着水势下降，各种源针叶可溶性糖的质量分数总体呈上升趋势，其中，浙江淳安种源上升幅度较大，200g·L^-1 PEG处理时增加了42．78％，300g·L^-1 PEG处理增加了49．01％，相比之下，广东信宜种源只分别增加了19．49％和37．15％，上升幅度较小。硝酸还原酶活性下降，贵州都匀种源下降幅度较小，广东信宜种源下降幅度较大。综合评价认为，不同种源马尾松耐旱性存在着较大的种内遗传变异性，贵州都匀和浙江淳安种源耐旱性相对较强，而广东信宜种源耐旱性相对较弱，图4表2参15

Physiological response from different provenances of Pinus massoniana seedlings to water stress

The objective of this study was to determine the physiological response from three different provenances （Xinyi of Guangdong Province, Chun＇ an of Zhejiang Province and Duyun of Guizhou Province ） of masson pine （Pinus massoniana ） to water stress. Water stress on masson pine seedlings from three provenances was applied using concentrations of 0 （control）, 100, 200, and 300 g ·L^-1 polyethylene glycol （PEG6000） for determining the concentrations of soluble sugar, peroxidase activity （POD） and nitrate reductase （NR） activity; and 0 （control）, 150, 250, 350 g ·L^-1 PEG 6000 for determining chlorophyll content and membrane permeability. As water stress increased from 0 to 250 g ·L^-1 PEG, chlorophyll content from each provenance decreased （ Xinyi - 17.51%, Chun＇an - 17.69%, and Duyun - 14. 98% ）. When treated with 350 g ·L^-1 PEG, the decrease compared to the control was： Chun＇an, 27.27% ; Xinyi, 25.70% ; and Duyun, 18. 21%. As PEG concentration went from 250 to 350 g ·L^-1, membrane permeability increased obviously. POD increased first and then decreased with the increasing of PEG concentration. When treated with 300 g ·L^-1 PEG, POD decreased compared to the control with Xinyi decreasing 43.90% , Chun＇an 23.99% , and Duyun 27.06%. Compared to no water stress, with 200 g ·L^-1 PEG, soluble sugar increased for Chun＇an （42. 78% ） and Xinyi （19.49%）, while at 300 g ·L^-1 PEG Chun＇an increased 49. 01% and Xinyi 37. 15%. Also, NR activity decreased with small changes for the Duyuan source but relatively large changes for the Xinyi source. This study showed that drought tolerance in Duyun and Chun＇an was stronger than the Xinyi provenance. [ Ch, 4 fig. 2 tab. 15 ref. ]