Department of Soils and Plant Nutrition, University of California, Berkeley, California 94720.
Plant Physiol. 1972 Feb;49(2):105-9. doi: 10.1104/pp.49.2.105.
Studies of the water relations of potassium deficient sugarbeet plants (Beta vulgaris L.) revealed two factors for stomatal closure. One component of stomatal closure was reversible by floating leaf discs on distilled water to relieve the water deficit in the leaves; the other component was reversible in the light by floating the leaf discs on KCl solution for 1 hour or more. Potassium-activated stomatal opening in the light was observed when the guard cells were surrounded by their normal environment of epidermal and mesophyll cells, just as observed by previous workers for epidermal strips. Leaf water potentials, like stomatal apertures, appear to be strongly related to leaf potassium concentration. Potassium-deficient plants have a greatly decreased root permeability to water, and the implications of this effect on stomatal aperture and leaf water potential are discussed. In contrast, petiole permeability to water is unaffected by potassium treatment.
对钾亏缺甜菜（Beta vulgaris L.）植株水分关系的研究揭示了引起气孔关闭的两个因素。叶圆片浮于蒸馏水上以解除叶片水分亏缺时，可使气孔关闭的一个组成部分可逆；叶圆片浮于 KCl 溶液中 1 小时或更长时间，在光下另一个组成部分也可可逆。当保卫细胞处于周围表皮细胞和叶肉细胞的正常环境中时，钾可激活光下的气孔张开，这正如前人对表皮条观察到的那样。正如气孔开度一样，叶水势似乎与叶内钾浓度有密切关系。缺钾植株的根对水的透性大大降低，这对气孔开度和叶水势的影响正在讨论之中。相反，叶柄对水的透性不受钾处理的影响。
