角果木和红海榄对低温胁迫的生理响应差异研究

Differences of physiological responses between Cerops tagal and Rhizophora stylosa against low-temperature stress

【目的】研究角果木(Cerops tagal)和红海榄(Rhizophora stylosa)2种红树对不同低温胁迫生理响应的差异,为2种红树的引种造林提供依据。【方法】以角果木和红海榄2种热带红树植物的枝条为材料,对其分别进行12,8,4,0,-4和-8℃的低温胁迫处理,以常温(25℃)下的枝条为对照,测定2种红树叶片的自由水/束缚水比值、相对电导率、游离脯氨酸含量及过氧化物酶(POD)、丙二醛(MDA)含量。【结果】随胁迫温度降低,2种红树的自由水/束缚水比值、电导率表现为温度≥0℃时小幅波动,<0℃时快速升高;POD活性和脯氨酸含量则呈先升后降的变化趋势,并于8℃达到峰值。胁迫过程中,红海榄的POD活性始终高于角果木,而自由水/束缚水比值和MDA含量始终低于角果木。【结论】角果木和红海榄通过提高酶活性和渗透调节物质的含量,来提高植物体的防御能力和减轻0℃以上的低温伤害,但2种红树均易受0℃以下低温的影响并产生冻害;红海榄的抗冷害能力强于角果木。

【Objective】 The physiological responses of Cerops tagal and Rhizophora stylosa against different low temperature stresses were studied.【Method】 Several cold-resistance physiological indexes of the leaves,such as the free water/bondage water ratio,conductivity,proline content,POD activity and MDA content,were measured through the treated branches of C.tagal and R.stylosa under temperatures of 12,8,4,0,-4 and-8 ℃,respectively and the untreated materials were used as control.【Result】 The proline contents and POD activities increased firstly and then dropped and the peaks were at 8 ℃ as temperature decreased.The free water /bondage water ratios and conductivities were characterized by small changes above freezing and by rapid increases below 0 ℃.The MDA were in accumulation as the stress temperature strengthened.The activities of POD in R.stylosa were always higher than that in C.tagal during the low temperature process while the contents of MDA and free water/bound water ratios in R.stylosa were lower than that in C.tagal.【Conclusion】 C.tagal and R.stylosa body defenses were improved and the injury of low temperature above freezing were reduced by increasing enzyme activity and osmolytes content.The two plants were easily affected and damaged below 0 ℃ and the ability of R.stylosa to resist damage was stronger than that of C.tagal.