台湾桤木和四川桤木种源苗木对水分胁迫的生理响应

采用PEG6000，研究了4种台湾桤木种源和2种四川桤木种源苗木对水分胁迫的生理响应。结果表明：（1）随着水分胁迫强度增加，叶片质膜相对透性增大，四川桤木种源质膜透性比台湾桤木种源增加幅度大。（2）在轻度的水分胁迫下，6个种源SOD活性均呈上升趋势，POD活性的增加只发生在PEG10％的水分胁迫强度以内，轻度水分胁迫下，MDA含量上升幅度小于重度胁迫强度；在PEG30％胁迫处理时，台湾桤木叶片MDA含量平均上升30．22％，而四川桤木上升了40．44％，表明台湾桤木种源膜脂过氧化程度较四川桤木种源轻，受害程度相对要小一些。（3）水分胁迫下，叶片脯氨酸含垃均有不同程度的增加．在PEG20％水分胁迫处理下，各种源脯氨酸积量增加的幅度为：台湾桤木苗栗种源（AF２）（68．9％）〉台湾桤木福建南平种源（AF４）（60．2％）〉台湾桤木台东种源（AF２）（54．7％）〉台湾桤木台中种源（AF1（47．6％）〉四川桤木广元种源（AC2）（39.7%）＞金堂种源（AC１）（39.1%）。水分胁迫条件下，叶片可溶性糖含量呈下降趋势。６种种源苗木在水分胁迫条件下，由于脯氨酸的积累，有一定的渗透调节能力，但这种渗透调节能力又是十分有限的。（４）采用隶属函数法，对各种源的抗旱生理进行综合评价，其耐旱牛理强弱的顺序是：AF2、AF1、AF3、AF4、AC2、AC1，台湾桤木比四川桤木具有较强的耐旱生理适应性。从耐旱生理角度讲，凡是适合四川桤木生长的区域，基本上亦适合台湾桤木，在引种载培中，应选择抗旱性稍强一些的台湾桤木苗栗种源和台中种源。

Physiological Responses of Alnus formosana and Alnus cremastogyme Nursery Stocks of the Different Provenances to Water Stress

PEG6000 was employed to study the physiological responses of the seedlings of four Alnus formosana provenances and the nursery stocks of two Alnus cremastogyme provenances to water stress and the result of the study revealed that: (1) As the water stress became intensified,the plasmalemma permeabilities of their leaves relatively increased and the nursery stocks of the Alnus cremastogyme provenances increased their plasmalemma permeability more than the nursery stocks of the Alnus formosana provenances did.(2) The nursery stocks of all the six provenances appeared to increase their SOD activities under light water stress and increased their POD activities under the water stress weaker than the stress resulting from 10% PEG;under light water stress,they increased their MDA contents more than the water stress was increased;under the water stress resulting from 30%,the Alnus formosana nursery stocks increased averagely their leaf MDA contents by 30.22% and the Alnus cremastogyme nursery stocks increased their MDA by 40.44%,which indicated that the membrane lipid in the nursery stocks of the different Alnus formosana provenances was less oxidized than that in the nursery stocks of the Alnus cremastogyme provenances,thus suffering slightly less injury.(3) Under water stress,the proline contents in the leaves appeared to differently increase.Under the water stress resulting from 20% PEG,the increments of the proline cumulants in the leaves of all the provenances decreased in the order of the Alnus formosana nusery stocks of Miaoli in Taiwan(AF_2)(68.9%),the Alnus formosana nusery stocks of Nanping in Fujian(AF_4)(60.2%),the Alnus formosana nusery stocks of east Taiwan(AF_3)(54.7%),the Alnus formosana nusery stocks of central Taiwan(AF_1)(47.6%),the Alnus cremastogyme nursery stocks of Guangyuan in Sichuan(AC_2)(39.7%) and the Alnus cremastogyme nursery stocks of Jintang in Sichuan(AC_1)(39.1%).Under water stress,the soluble sugar contents in the leaves appeared to decline.The nursery stocks of the six provenances presented certain capabilities of osmotic regulation because their proline accumulations but the capabilities were very limited.(4) The drought resistances of the nursery stocks of all the provenances were comprehensively evaluated by Membershipfunction method.Their drought resistances were shown to decrease in the order of AF_2,AF_1,AF_3,AF_4,AC_2 and AC_1,and thus Alnus formosana was more resistant to drought than Alnus cremastogyme.In light of their drought resistances,the areas suitable for Alnus cremastogyme will be basically suitable for Alnus formosana,and so the Alnus cremastogyme nursery stocks of Miaoli in Taiwan and central Taiwan had better be chosen in nursery stock introduction