低温胁迫对3种蕨类植物生理指标的影响

Effects of low temperature stress on physiological indexes of three species of ferns

【目的】探索低温胁迫环境(0℃)对3种蕨类植物生理生化指标及光合特性的影响。【方法】以鸟巢蕨(Asplenium nidus)、波士顿蕨(Nephrolepis exaltata cv.Bostoniensis)和狼尾蕨(Davallia trichomanoides)3种蕨类为试验材料,在低温胁迫(0℃)下不同时间点0 h(CK)、48 h、96 h和恢复常温(20℃)48 h处理后测定其相关生理生化及光合指标。【结果】随低温胁迫持续时间的延长,3种蕨类植物叶片的相对电导率、可溶性糖含量、可溶性蛋白含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性总体上均呈上升趋势,恢复常温(20℃)48 h后各指标均有所降低。叶绿素含量和丙二醛(MDA)含量变化趋势不同;随低温胁迫持续时间的延长,3种蕨类植物叶片的净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))及水分利用率(WUE)等光合参数均显著下降,胞间CO_(2)浓度(C_(i))上升,恢复常温(20℃)48 h后3种蕨类植物叶片的P_(n)、T_(r)、G_(s)及WUE等光合参数均有一定程度的回升,Ci浓度下降;主成分分析表明,主成分1中最大的特征向量是P_(n),其次是T_(r)和WUE,主成分2中最大的特征向量是叶绿素,其次是可溶性蛋白和可溶性糖。【结论】3种蕨类植物对低温胁迫的响应存在差异,利用隶属函数法进行综合评价,得出3种蕨类低温胁迫下耐受性强弱顺序为鸟巢蕨>狼尾蕨>波士顿蕨。

【Objective】The present research was to explore the effects of low temperature stress(0℃)on physiological,biochemical indexes and photosynthetic characteristics of three ferns.【Method】Asplenium nidus,Nephrolepis exaltata cv.Bostoniensis and Davallia trichomanoides were used as experimental materials.After low temperature stress(0℃)for 48 hours,96 hours and 48 hours recovered at air temperature(20℃),the physiological,biochemical and photosynthetic indexes were measured.【Result】With the increase of the exposure to low temperature,the relative electrical conductivity(REC),the contents of soluble protein and sugar superoxide diamutase(SOD)and peroxidase(POD)activities increased in three fern species in general.These indexes were decreased at 48 hours under 0℃and increased when the ferns were subjected to air temperature(20℃).The chlorophyll and malondialdehyde contents had different trends.With the increase of the treatment time(0℃),the net photosynthetic rate(P_(n)),transpiration rate(T_(r)),stomatal conductance(G_(s))and water use efficiency(WUE)decreased,and the intercellular CO_(2)concentration(C_(i))increased in three fern species.The Pn,Tr,Gsand WUE in the three fern species rose again in some extent,whereas their Cidecreased in some extent after cessation of the low temperature treatment,which was important regulatory mechanism for the acclimation of these three fern species to low temperature stress.Principal component analysis showed that the largest eigenvector in principal component 1 was Pn,followed by Trand WUE,the largest eigenvector in principal component 2 was chlorophyll,followed by soluble protein and soluble sugar.【Conclusion】The responses of the three ferns to low temperature stress were different.Using the membership function method for comprehensive evaluation,the tolerance of three fern species under low temperature stress was in the order of A.nidus>D.trichomanoides>N.exaltata cv.Bostoniensis.