Study On The Effect Of Physiological Response To Pear-Jujube Tree Under RDI

The paper studied physiological mechanism to pear-jujube tree under RDI,The experiment was conducted in the laboratory of Northwest A&F University, shanxi province.According to growth characteristic of pear-jujube tree, five growth stages was use for deficit stages of the experiment as follows:Winter dormancy, leaf stage, flowering and fruit setting, fruit enlargement and fruit maturity, There were five treatments.The deficit of single and whole growth stages was used. The research fruit wan as follows:(1)The relationship between evaporation and surface soil water content is linear 90% root of pear-jujube tree concentrated on the 0-80cm soil layer, which is the main layer for tree absorb water and nutrients.So this experiment designed 0-80cm soil layer for the scheming humid layer. The variation of soil water content under different treatments is same. The vary of soil water content change is smaller than fully irrigation. It proves that RDI could save water.(2)RDI had significant effects on the sap flow of pear-jujube tree. This experiment reference to the previous experiment on the relationship between transpiration rate and sap flow found that:the change of sap flow behind the change of transpiration rate about 1 hour.This because water transport in the plant need time.this experiment show that:the variation of sap flows in the peer-jujube trees during the day and the night are obviously different.During the day they exhibit an irregular inverted-U relationship and obviously fluctuate at noon.The total amount of sap flow are different in every grow stages. Based on the test data can be obtained that the number of sap flow on stage of bud leaf expansion, stage of fruit enlargement and ripe stage can account to 75% for the whole growing period. The study indicates that, the variation of sap flows is a combined result of solar radiation and daily average temperature. The variation of sap flow linearly with solar radiation and daily average temperature, the coefficient is 0.7235 and 0.5594.(3)The variation of geotemperature in green house is a combined result of solar radiation, outside air temperature and soil water content. There are significant correlation between geotemperature and solar radiation and correlates negatively linearly with soil water content. The variation of geotemperature under different treatments is same. With the increase of depth the geotemperature is reduce. The geotemperature under fully irrigation below than RDI in summer.(4)The results indicate that:RDI had impact on quality and yield.The yield is biggest for fully irrigation which is 1400kg/a,Expect treatment 3,other treatments yield are not reduce greatly compact with the controlled treatment. But the treatment that suffered serious water deficit during flowering decreased average fruit weight, fruit volume and Vc. The decrease of T2-T5 average fruit weight 10.6%,8.4%,8.0%,3.7% respectively. The volume of fruit under fully irrigation is 25.20cm3 while it is 20.15 cm3 under 2 treatment,Compared with fully irrigation,the volume was deceased 20%.The influence to the fruit water content and soluble protein content for all the treatments are similar. All the treatments could elevated the content of Vc, soluble solid matter and sugar.The results indicate that all the treatments elevated the content of sugar about 37.5%,18.1%,26.1% and 9.5%respectively compact with the controlled treatment. It indicates that RDI could elevate the quality of fruit.(5)RDI have different influence to the leaf water use efficiency(WUE). The WUE under lightly is high then moderately irrigation. In some grow stages RDI could increasing WUE. According to the study showed that:different water regulated controlled on different growth period had inhibition role to plant branch.