Electrical signalling and cytokinins mediate effects of light and root cutting on ion uptake in intact plants.-猫眼课题宝

电信号和细胞分裂素介导光和根部切割对完整植物离子吸收的影响。

DOI：

发表时间：

2009

期刊：

Plant, Cell and Environment

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

S. Shabala;Jiayin Pang;Meixue Zhou;L. Shabala;T. Cuin;Peter Nick;Lars H. Wegner

成熟根区的养分吸收受地上部和根尖的系统控制。在玉米中，芽暴露于光诱导短期（1-2分钟内）的净K+和H+在根表面的运输的影响。H+流出减少（从-18至-12 nmol m（-2）s（-1）），K+摄取（约2 nmol m（-2）s（-1））恢复为流出（约-3 nmol m（-2）s（-1））。木质部探测发现，跨根（电）之间的木质部血管和外部电极的电位下降响应在几秒钟内逐步增加的光强度;木质部压力开始下降后，约3分钟的延迟，有利于电，而不是液压信号。切割玉米和大麦根在基地减少H+外流和停止K+流入低盐介质中，木质部压力迅速增加到大气水平。随着100毫米氯化钠添加到浴中，切割时的压力跳变更显着，但通量保持不受影响，提供了进一步的证据，对离子吸收的液压调节。切除大麦根的顶端部分后，流入变为大量流出（-50 nmol m（-2）s（-1））。激动素（2-4 μ M），一种合成的细胞分裂素，逆转了这种作用。根尖合成的细胞分裂素的离子运输的调节进行了讨论。

Nutrient acquisition in the mature root zone is under systemic control by the shoot and the root tip. In maize, exposure of the shoot to light induces short-term (within 1-2 min) effects on net K+ and H+ transport at the root surface. H+ efflux decreased (from -18 to -12 nmol m(-2) s(-1)) and K+ uptake (approximately 2 nmol m(-2) s(-1)) reverted to efflux (approximately -3 nmol m(-2) s(-1)). Xylem probing revealed that the trans-root (electrical) potential drop between xylem vessels and an external electrode responded within seconds to a stepwise increase in light intensity; xylem pressure started to decrease after a approximately 3 min delay, favouring electrical as opposed to hydraulic signalling. Cutting of maize and barley roots at the base reduced H+ efflux and stopped K+ influx in low-salt medium; xylem pressure rapidly increased to atmospheric levels. With 100 mm NaCl added to the bath, the pressure jump upon cutting was more dramatic, but fluxes remained unaffected, providing further evidence against hydraulic regulation of ion uptake. Following excision of the apical part of barley roots, influx changed to large efflux (-50 nmol m(-2) s(-1)). Kinetin (2-4 microM), a synthetic cytokinin, reversed this effect. Regulation of ion transport by root-tip-synthesized cytokinins is discussed.

Cytokinin stimulates dihydropyridine-sensitive calcium uptake in moss protoplasts.