自然降温过程中3种樟树渗透调节物质的动态变化

依据越冬期间叶片内脯氨酸、可溶性糖等渗透调节物质含量及电解质渗透率的变化,对尾叶樟Cinnamomum camphora、猴樟C.bodinieri和樟C.caudiferum 3种樟树的自然降温胁迫响应特性及抗寒能力进行对比研究.结果表明:自然降温过程中,12月中旬前,渗透调节物质含量及电解质渗透率变化不明显,可能与低温持续时间较短,且气温又时有回升相关;进入1月后,连续4 d-8℃的低温(1月5—8日)造成了渗透调节物质含量的迅速增加.与12月28日相比,1月9日3种樟树可溶性蛋白含量分别增加了16.59%、43.44%和24.29%,可溶性含量分别增加了8.19%、21.27%和16.72%,其中猴樟和樟的增幅均达到显著水平.之后,随着气温的持续降低,过度的低温胁迫导致渗透调节物质含量下降和电解质渗透率上升;春季,随着气温的逐渐回升,渗透调节物质含量又略有上升,而电解质渗透率则呈明显的下降态势.结合隶属函数法的应用,得出自然越冬过程中樟树的抗寒性呈先增强后减弱再增强的变化.综合评价结果显示,抗寒性强弱顺序为:猴樟>樟>尾叶樟,这与越冬期间外部形态观察的结果基本一致.

Dynamic Changes in Osmotic Adjustment Substance of Three Camphor Species Under Natural Cooling

By using Cinnamomum bodinieri,C.camphora and C.caudiferum as experimental materials,dynamic variations in soluble sugar,proline,soluble protein and the leakage rate of electrolyte were investigated in the process of natural cooling from October 2009 to April 2010,and their comparison was analyzed to identify the cold resistance of three camphor tree species.The results indicated that in the process of natural cooling,before the middle of December,with a shorter duration of low temperature,the leakage rate of electrolyte changed with temperature but the change was not significant.In January,the content of osmotic adjustment substance increased rapidly with four successive days of low temperature at-8 ℃.Compared with December 28,2009,the content of soluble protein and soluble sugar increased by 16.59%,43.44%,24.29 % and 8.19%,21.27%,16.72 % on 9 January,2010,and the increase amplitude of C.bodinieri and C.caudiferum reached a significant level.As temperatures continued to decrease,the content of osmotic adjustment substance decreased and the leakage rate of electrolyte increased;from February to March,as the temperature increased,soluble protein and proline content increased again,but the leakage rate of electrolyte reduced to the minimum,which indicated that the damage of cell membrane caused by low temperature gradually restored;a fuzzy mathematics method showed that the cold resistance of the camphor trees first increased and then reduced,but finally further strengthened.The cold tolerance abilities are ranked in the following order: C.bodinieri>C.camphora>C.caudiferum.