分析测试百科网 > 行业资讯 > 技术原理

蓝光诱导黄化野生型和向光素突变体拟南芥幼苗的H+和...

2020.7.20

蓝光诱导黄化野生型和向光素突变体拟南芥幼苗的H+和Ca2+流

Abstract

Ion flux kinetics associated with blue light (BL) treatment of two wild types (WTs) and the phot1, phot2 and phot1/phot2 mutants of Arabidopsis were studied by using the MIFE noninvasive ion-selective microelectrode technique. BL induced significant changes in activity of H⁺ and Ca²⁺ transporters within the first 10 min of BL onset, peaking between 3 and 5 min. In all WT plants and in phot2 mutants, BL induced immediate Ca²⁺ influx. In phot1 and phot1/phot2 mutants, net Ca²⁺ flux remained steady. It is suggested that PHOT1 regulates Ca²⁺ uptake into the cytoplasm from the apoplast. Changes in ion fluxes were measured from cotyledons of intact seedlings and from the cut top of the hypocotyl of decapitated seedlings. Thus the photoreceptors mediating BL-induced Ca²⁺ and H⁺ fluxes are present in the rest of the decapitated seedling and probably in the cotyledons as well. The H⁺ and Ca²⁺ flux responses to BL appear not to be linked because, (i) when changes were observed for both ions, Ca²⁺ flux changed almost immediately, whereas H⁺ flux lagged by about 1.5 min; (ii) in the Wassilewskija ecotype, changes in H⁺ fluxes were small. Finally, wave-like changes in Ca²⁺ and H⁺ concentrations were observed along the cotyledon–hook axis regardless of its orientation to the light.

蓝光是控制植物生长和形态发育的重要因子，引起植物子叶扩展，抑制胚轴伸长，这些反应发生的同时或者随后伴随着膜电势和离子转运的变化。非损伤微测技术由于其非损伤性、长时间监测、动态测量和易操作的特点则能非常好地研究离子转运的问题。

使用非损伤微测技术（MIFE）研究了H⁺和Ca²⁺离子流动力学和拟南芥蓝光响应的关系：发现蓝光处理的最初10min内诱导了H⁺和Ca²⁺转运体活性的显著变化，3-5min时变化达到最大，蓝光立即诱导了野生型和phot2突变体Ca²⁺内流，而phot1和phot1/phot突变体中Ca²⁺流保持稳定，说明PHOT1调节Ca²⁺从质外体吸收进入细胞质；另外，发现光受体调节的H⁺和Ca²⁺流存在于切掉胚轴尖端的幼苗，并可能也存在于子叶中，沿着子叶弯勾到胚轴处观察到了Ca²⁺和H⁺浓度有波浪形的变化。Ca²⁺流在蓝光处理下几乎立即就出现，但是H⁺流滞后了1.5min，而在野生型中H⁺流变化很小。