CHIPS AND TIPS - A REVIEW ON WATER CHANNEL

Water channels are intrinsic proteins of the tonoplast or plasma membr ane and supposedly regulate symplastic water transport. They are gated , thereby providing a water transport facility through the plasma memb rane following an osmotic gradient. Water channels are highly selectiv e for water molecules and enable rapid and effective regulation of sym plastic water transport in plants. This regulation is by a sensitive c losing mechanism, induced by protein phosphorylation, in the short and by distribution and frequency disintegration and de novo synthesis of water channel protein in the long term. These joint mechanisms are de signated as water channel activity. The estimated half-life is several hours. The present review summarises present knowledge on their struc ture, function, and regulatory mechanisms as well as their potential r ole in horticultural science.