《植物生理学报》 2013, 49(3): 264-272

外源ABA对拟南芥根系皮层细胞水力学特征的影响

张静媛^1,2, 慕自新², 张岁岐^1,2,*

西北农林科技大学1黄土高原土壤侵蚀与旱地农业国家重点实验室, 2生命科学学院, 陕西杨凌712100

通信作者：张岁岐；E-mail: sqzhang@ms.iswc.ac.cn；Tel: 029-87010897

摘　要：

在溶液培养条件下, 以拟南芥野生型哥伦比亚(Col)、兰兹伯格(Ler)和ABA胞质受体PYR/PYL/RCAR四突变体pyr1;pyl1;pyl2;pyl4 (Qm)为试验材料, 利用细胞压力探针技术对不同浓度外源ABA和不同时间处理下的根系皮层细胞的细胞膨压(P)、水分跨膜运输半时间(TW1/2)、细胞壁体积弹性模量(ε)以及细胞水导(Lp)进行测定, 从分子遗传学水平探讨ABA影响拟南芥根系水力学特性的早期信号。结果表明, 外源ABA处理使野生型Col和Ler根系皮层细胞的水力学性质产生不同的变化, 其中, 细胞膨压(P)在处理前后无变化; 细胞壁弹性模量(ε)随ABA浓度及ABA处理时间变化而发生变化, 但变化趋势不明显; 而外源ABA处理使TW1/2和Lp发生明显变化, 即TW1/2随ABA浓度升高而降低, 对于同一浓度处理而言, TW1/2则随ABA处理时间的延长先降低后增加, 各浓度在处理60 min时均降到最低值, 即TW1/2在1 000 nmol·L-1下处理60 min达到最低值, 而在处理120 min时TW1/2又恢复, 趋近于对照的值; 相反Lp在1 000 nmol·L-1下处理60 min时达到最大值, 处理120min时恢复到对照水平, 即表现出瞬时效应。与野生型Col和Ler相比, Qm的TW1/2及Lp均对外源ABA不敏感。说明ABA提高了拟南芥根系皮层细胞的透水作用, 而且ABA受体PYR/PYL/RCAR介导的信号转导参与了ABA的水分调节效应。

关键词：外源ABA; 拟南芥; 细胞压力探针; 根皮层细胞; 水力学参数

收稿：2013-01-17   修定：2013-01-29

资助：国家自然学基金项目(30971714)和高等学校学科创新引智计划(B12007)。

Effects of Exogenous ABA on Root Cortex Cell Hydraulics of Arabidopsis thaliana

ZHANG Jing-Yuan^1,2, MU Zi-Xin², ZHANG Sui-Qi^1,2,*

¹State Key Laboratory of Soil Erosion and Dryland Farming of the Loess Plateau, ²College of Life Science, Northwest A&F Uni-versity, Yangling, Shaanxi 712100, China

Corresponding author: ZHANG Sui-Qi; E-mail: sqzhang@ms.iswc.ac.cn; Tel: 029-87010897

Abstract:

By using hydroponic culture, the plant materials in this research include two wild-type Arabidopsis thaliana (Col and Ler) and a mutant (Qm). In this research, we use cell-pressure probe to investigate the effects of ABA on different Arabidopsis thaliana hydraulic properties and explore the early signal about the influence of exogenous ABA on hydraulics of Arabidopsis thaliana root cortex cell in the level of molecular genetics. Hydraulic properties of roots were examined under different ABA concentrations and treatment periods. The re-sults indicate that exogenous ABA treatments have different effects on hydraulics properties in root cortical cells of wild-type (Col) and (Ler). First, we found that, P remained the same as the exogenous ABA treatments went on. Meanwhile, the variation of ε correlated with the changing of ABA concentration and treatment time, but there were not remarkable variation. However, exogenous ABA has significant effects on half-time of water exchange (TW1/2) and hydraulic conductivity (Lp). Specifically, half-time of water exchange (TW1/2) of wild-type (Col) and (Ler) gradually decrease as ABA concentration and treatment period rise. Results show that TW1/2 reaches the minimum when plants are treated for 60 min at concentration of 1 000 nmol·L-1, while Lp reached the maximum value, under the same condition, then the value of TW1/2 and Lp recovered to the value of control after 2 h. It means that exogenous ABA has instantaneous effect on root cortex cells’ hydraulics. Comparing with wild species, exogenous ABA do not have significant influence on TW1/2 and Lp of Qm which is a quadruple (pyr1;pyl1;pyl2;pyl4) mutant. The evidances reveal that ABA can improve the root cortex cells’ hydraulic abili-ty of Arabidopsis thaliana and the signal transduction pathway mediated by ABA receptor PYR/PYL/RCAR gets involved in the ABA-induced effects of water uptake.

Key words: exogenous ABA; Arabidopsis thaliana; cell-pressure probe; hydraulic properties