Departamento de Agronomía, Escuela Técnica Superior de Ingenieros Agrónomos y Montes, Universidad de Córdoba, Campus de Rabanales, Ctra. Madrid-Cádiz Km. 396, E-14071 Córdoba, Spain.
J Exp Bot. 2010 Feb;61(4):1139-45. doi: 10.1093/jxb/erp379. Epub 2010 Jan 6.
The effect of water stress on stomatal closure in sunflower plants has been found to be dependent on K(+) nutrient status. When plants with different internal K(+) content were subjected to a water-stress period, stomatal conductance was reduced more markedly in plants with an adequate K(+) supply than in K(+)-starved plants. K(+) starvation promoted the production of ethylene by detached leaves, as well as by the shoot of whole plants. Water stress had no significant effect on this synthesis. The effect on stomatal conductance of adding 5 microM cobalt (an ethylene synthesis inhibitor) to the growing medium of plants subjected to water stress was also dependent on their K(+) nutritional status: conductance was not significantly affected in normal K(+) plants whereas it was reduced in K(+)-starved plants. Cobalt had no harmful effects on growth, and did not alter the internal K(+) content in the plants. These results suggest that ethylene may play a role in the inhibiting effect of K(+) starvation on stomatal closure.
已发现水分胁迫对向日葵植株气孔关闭的影响取决于 K(+)营养状况。当具有不同内部 K(+)含量的植物经历水分胁迫期时，与 K(+)饥饿植物相比，充足 K(+)供应的植物的气孔导度降低更为明显。K(+)饥饿促进了乙烯的产生，无论是在离体叶片中，还是在整株植物的茎中。水分胁迫对这种合成没有显著影响。将 5 μM 钴（一种乙烯合成抑制剂）添加到经受水分胁迫的植物的生长介质中，对气孔导度的影响也取决于它们的 K(+)营养状况：在正常 K(+)植物中，导度没有显著影响，而在 K(+)饥饿植物中则降低。钴对生长没有有害影响，也不会改变植物内部的 K(+)含量。这些结果表明，乙烯可能在 K(+)饥饿对气孔关闭的抑制作用中发挥作用。
