沙生柽柳扦插生根过程插穗相关理化特征分析

选取沙生柽柳半木质化枝条进行苗床扦插,通过实验测定插穗生根过程中内源激素(IAA、GA3、ZR、ABA)含量、可溶性营养物质(糖、蛋白质)含量及相关氧化酶(PPO、POD、SOD、IAAO)活性的动态变化特征,探讨沙生柽柳插穗扦插生根机理。结果表明:(1)沙生柽柳插穗内源激素含量随生根进程而发生变化,其中,IAA含量在扦插35d最大,并出现较大的波动变化;ZR含量在扦插55d前后变化明显,呈现低水平向高水平转化趋势;ABA、GA3含量依次呈先升高后降低再升高的变化过程,并在扦插15d和55d(80d)呈现变化的峰值和谷值。(2)沙生柽柳扦插生根与相关氧化酶活性密切相关,其中,POD、IAAO活性在插穗扦插35d后长时间保持较高水平,直至插穗生根后POD活性明显降低,IAAO活性有所增加;PPO、SOD活性则在插穗扦插15d保持较高活性,且PPO活性的变化均匀,SOD活性的高低交替变化明显。(3)在沙生柽柳扦插生根期间,插穗可溶性糖含量呈现生根前消耗减少与生根后积累增加两大变化过程,可溶性蛋白质含量表现为扦插后逐步积累增加的变化趋势。研究表明,高水平的IAA、ZR和低水平的GA3、ABA共同调控着沙生柽柳插穗生根;IAA能够通过促进插穗POD、PPO、IAAO活性变化来影响生根,较高的POD、IAAO活性可调节插穗IAA水平,高水平的PPO活性则催化插穗IAA-酚酸复合物的形成,进而诱导插穗生根。

Physiological and Biochemical Characteristics of Tamarix taklamakanensis Cuttings during Rooting Stages

In order to explore asexual reproduction root mechanism of Tamarix taklamakanensis, we collected semi hard wood stems of T. taklamakanensis and measured the contents of endogenous hormones IAA, GA3, ZR and ABA during the rooting period, and soluble sugar and protein contents and the related enzyme activities such as PPO, POD, SOD and IAAO in stems during cuttings. The results showed as follows: (1) the endogenous hormones of T. taklamakanensis varied with the process of rooting. The content of IAA can get the maximum at 35 days of cutting and shown a big fluctuation. The content of ZR changed significantly at about 55 days after cutting, showing low level to high level conversion trend. The contents of ABA and GA₃ showed the process of increasing, then decreasing and then increasing, and showed the peak and the trough of change on the 15th and 55th or 80th days of cutting. (2) The rooting of T. ramosissima was closely related to oxidase activities, POD and IAAO were kept at a high level for 35 days after cutting, POD activity decreased significantly and IAAO activity increased after root cutting, PPO and SOD maintained a high activity in 15 days after cuttage cutting, and the changes of PPO activity were even and the changes of SOD activity alternated obviously. (3) Soluble sugar content of rooting cuttings showed two major changes are consumption reduced before rooting and accumulation increased after rooting. Soluble protein content showed a trend of increasing accumulation gradually after cutting. Studies have shown that high levels of IAA, ZR and low levels of GA₃, ABA controled rooting cuttings together, and at the same time, IAA can promote the changes of POD, PPO and IAAO activities to affect rooting, higher activities of POD and IAAO can adjust the IAA level, high level of PPO catalyze the formation of the IAA phenolic acid complex and then induce cuttings rooting.