Study On The Relationship Between The Change Of The Physiology Index And Permanent Wilting Of The Cutting In Several Trees

The water potential of the xylem plant wound fall down when in the drought stress, and the cavitation wound become serious and lead to the embolism happen, which limit the water transport; and at the same time the plant wound happen to wilting in drought stress and permanent wilting in the serious drought stress. So we probe into the relationship between the cavitation and permanent wilting through the experiment.Through using drought treatment and rewatering under different drought conditions to several kinds of the annual cutting, observed the growth and study the physiology change of the cutting under different soil drought. The results showed that: in the experiment condition, different kinds of the cutting were rewatered in the slight drought, the cuttings still regrew and took root and survived during these period. Although their physiology had some reduced, the rule didn't change. These cuttings which were rewatered after the given day wound die away and permanent wilting at last though got enough water. The water potential decreased quickly and didn't display"V"daily variation, but declined continually to when it got to the lowest value of intraday time until could't detect the water potential with pressure chamber, so the water potential had a break change, the daily variation of the leaf transpiration rate were broken, and decreased quickly, had break change, then declined continually. Photosynthetic rate reduced to smoothly and removed to earlier time until vanished but no break change.In this experiment, we thought the water potential and transpiration rate of these kinds of cuttings declind slowly and the cavitation wound become more serious which lead to the hydraulic conductivity reduce with the water content of the cuttings when the water content fall down.When the drought stress exceed the bound, the stomatal wound close, which lead to the transpiration rate wound reduced quickly, the water potential wound have break change at the same time or latter. The water potential can reflect the water content of the cuttings, which mean the break changepf water content of the cutting lead cutting permanent wilting.We still found that, through calculate the water use efficiency of different treatment to the cutting, these cutting which received slight drought stress have higher value of the water use efficiency than other treatment, but the different trees have different treatments.