Zivanović B D, Pang J, Shabala S
School of Agricultural Science, University of Tasmania, Hobart, Tasmania, Australia.
Plant Cell Environ. 2005 Mar;28(3):340-52. doi: 10.1111/j.1365-3040.2005.01270.x.
Net fluxes of H+, K+ and Ca2+ ions from maize (Zea mays L.) isolated leaf segments were measured non-invasively using ion-selective vibrating microelectrodes (the MIFE technique). Leaf segments were isolated from the blade base, containing actively elongating cells (basal segments), and from non-growing tip regions (tip segments). Ion fluxes were measured in response to bright white light (2600 micromoles m-2 s-1) from either the leaf segments or the underlying mesophyll (after stripping the epidermis). Fluxes measured from the mesophyll showed no significant difference between basal and tip regions. In leaf segments (epidermis attached), light-induced flux kinetics of all ions measured (H+, Ca2+ and K+) were strikingly different between the two regions. It appears that epidermal K+ fluxes are required to drive leaf expansion growth, whereas in the mesophyll light-induced K+ flux changes are likely to play a charge balancing role. Light-stimulated Ca2+ influx was not directly attributable either to leaf photosynthetic performance or to leaf expansion growth. It is concluded that light-induced ion flux changes are associated with both leaf growth and photosynthesis.
使用离子选择性振动微电极（MIFE技术）对玉米（Zea mays L.）离体叶片切段中的H+、K+和Ca2+离子净通量进行了非侵入性测量。叶片切段取自叶片基部（含有活跃伸长细胞，即基部切段）和非生长的叶尖区域（叶尖切段）。测量了叶片切段或去除表皮后的叶肉组织对明亮白光（2600微摩尔·米-2·秒-1）的离子通量响应。从叶肉组织测得的通量在基部和叶尖区域之间没有显著差异。在带有表皮的叶片切段中，两个区域中所有测得离子（H+、Ca2+和K+）的光诱导通量动力学显著不同。似乎表皮K+通量是驱动叶片扩展生长所必需的，而在叶肉组织中，光诱导的K+通量变化可能起电荷平衡作用。光刺激的Ca2+内流既不直接归因于叶片的光合性能，也不直接归因于叶片扩展生长。得出的结论是，光诱导的离子通量变化与叶片生长和光合作用都有关。
