摘要
用不同浓度HgCl2 、LaCl3 和TEACl (Tetraethylammoniumchloride)处理蚕豆 (Viciafaba)叶片下表皮条 ,发现HgCl2 能显著抑制气孔开闭 ,Ca2 + 通道阻塞剂LaCl3 或K+ 通道阻塞剂TEACl处理也都有一定程度的抑制。三者的作用效果HgCl2 >>LaCl3 >TEACl。用HgCl2 +LaCl3 、HgCl2 +TEACl或HgCl2 +LaCl3 +TEACl处理 ,则气孔开闭运动几乎完全被抑制。表明 :蚕豆气孔运动中 ,保卫细胞胀缩主要是水通道直接参与保卫细胞与叶肉细胞间水流的调节引起的 ,离子通道起间接次要作用 ,二者共同引起保卫细胞体积变化而导致气孔开闭。
A network of ion channels, which controls stomatal movements, has been well characterized in the plasma and vacuolar membranes of guard cells. However, it is still not clear how water flows through the membranes to regulate guard cell volumes. Water channels, which can specifically and quickly promote the transportation of water, have been found in the plasma and vacuolar membranes of guard cells. It is suggested that water may flow through water channels during stomatal movements and water channels may be involved in stomatal movements with ion channels. Broad bean (Vicia faba L.) was grown in pots and watered every three days to keep the soil moisture level at 80%±5% soil water capacity. Three-week-old fully expanded leaves were harvested. The abaxial epidermis was peeled off and soaked in the MES/KOH buffer containing different salts in different concentrations. Stomatal movements and states were observed and open stomata/total stomata ratios recorded from randomly selected fields under the microscope. Stomatal movements appeared to be inhibited by the addition of HgCl_2 at 0.8 mmol·L -1 concentration, while LaCl_3 (at 0.5 mmol·L -1) or TEACl (at 5 mmol·L -1) (Tetraethylammonium chloride) had little effect. The effect of HgCl_2 could beneutralized by 5 mmol·L -1 β-mercaptoethanl (ME). Stomatal movements were almost completely inhibited under HgCl_2+LaCl_3, HgCl_2+TEACl, or HgCl_2+LaCl_3+TEACl treatments LaCl_3, as Ca 2+ channel blocker, could affect stomatal movements by the inhibition of the changes of guard cell cytosolic Ca 2+ concentration or the blockage of Ca 2+ signal transduction pathway. TEACl, as K+ channel blocker, inhibited the changes of guard cell cytosolic K+ concentration to affect stomatal movements. HgCl_2 affected stomatal movements by the inhibition of water channels. All of them were involved in the regulations of water fluxes between guard cells and mesophyll cells directly or indirectly and affected stomatal movements significantly. Data appeared that they affected stomatal movements by HgCl_2>>LaCl_3>TEACl. Above results suggested that the environmental factors might affect stomatal movements in two ways: i) water channels activities were regulated and water flowed quickly across the membranes to control guard cell volumes. Some special stomatal movements, such as stomatal oscillation, could happen in this way; ii) ion channels activities were regulated and ions flowed across the membranes to change the osmotic or water potentials. Here water flows were transported with ion fluxes by co-transport or anti-transport. Previous studies have proposed pathways for regulating stomatal movements from the point of view of ions. However, from our study, it is evident that water channels may play an important part in regulating stomatal movements.
出处
《植物生态学报》
CAS
CSCD
北大核心
2002年第6期656-660,共5页
Chinese Journal of Plant Ecology
基金
国家重点基础研究规划项目 (G1999011705 )
国家自然科学基金项目 (3 0170161)
关键词
蚕豆
气孔运动
水通道
离子通道
作用
地位
Vicia faba L., Water channel, Ion channels, Stomatal movements
