Functions of water channel in the growth and development of horticultural crops.

（1）梨液泡膜水通道（TIP）蛋白质含量在幼果期较高，而葡萄TIP和质膜水通道（PIP）蛋白质含量在果实发育过程中基本保持不变。这表明，水通道在果实发育过程中起着水分调节作用，而不是果实发育过程中的水分调节作用.（2）TIP基因在梨幼果中表达量较高，而PIP基因在梨果实发育过程中表达量基本稳定。TIP和PIP基因在果实中的表达量明显高于其它器官，表明了水分通道在果实中的重要性。（3）使用仅识别磷酸化的PIP 2的抗体测定PIP 2的磷酸化。2、萝卜的水通道（1）TIP和PIP蛋白和基因在幼根和下胚轴的中心柱、叶柄的维管束鞘等发育组织或维管组织中表达量较高。这符合生理功能。（2）测量来自表达每种TIP或PIP的酵母的膜的水转运。TIP和PIP 2运输水。另一方面，PIPI不运输水，它可能发挥水运输以外的作用。(3)By渗透胁迫或植物激素处理萝卜幼苗后，TIP和PIPL的mRNA和蛋白水平没有变化，但PIP 2的mRNA和蛋白水平发生了变化。这些结果表明TIP和PIP为管家型，而PIP 2为环境诱导型。（4）萝卜下胚轴的表皮细胞和主根的薄壁细胞都有高水平的水通道表达，它们的水分运输活性也很高（300-500 mm/s）。

1, Water Channel in Fruit(1)Protein level of tonoplast water channel (TIP) of pear was high in young fruit, on the other hand, that of TIP and plasma membrane water channel (PIP) of grape berry was the almost constant during development. This suggests that water channel a play role in water regulation rather than fruit development.(2)Gene expression of TIP was high in young pear fruit, but that of PIP showed almost constant level during development. Gene expressions of TIP and PIP in fruit was especially higher than those in other organs, suggesting the importance of water channel in fruit.(3)Phosphorylation of PIP2 was determined using the antibody which could recognize only phosphorylated PIP2. PIP2 was de-phospholylared by salt and osmotic stresses and also in the fruit in day time.2, Water Channel in Radish(1)Protein and gene expressions of TIP and PIP were high in developing tissue or vascular tissue, such as central cylinder in young root and hypocotyl, and bundle sheath in petiole. This meets physiological function.(2)Water transport of the membrane from yeast expressed each TIP or PIP was measured. TIP and PIP2 transported water. On the other hand, PIPI did not transport water and it might play a role other than water transport.(3)By the treatment of osmotic stress or plant hormone to radish seedling, mRNA and protein levels of TIP and PIPL did not change, but those of PIP2 did. These results show that TIP and PIP are housekeeping type and PIP2 is environmentally inducible one.(4)The epidermis cells of hypocotyl and the parenchyma cells of taproot of radish were expressed water channels at high levels and their water transport activities were also high (300-500 mm/sec).