Study On Photosynthetic Characteristics Of Junzao-Jujube In Akesu Area Xinjiang

Ziziphus jujube Mill,is native to China's Yellow River,is one of the important economic cultivation of trees.This study takes 3 years'junzao-jujube as the materials.we investigated the Photosynthetic characteristics comparatively by Li-6400 photosynthesis portable in field from May to November,2010,in Xinjiang Aksu.the results are as follows:1. The diurnal variation curves at different phenological date of junzao-jujube were not the same.At the flowering and fruit enlargement stages,the diurnal variation showed a typical double-peak curve,but there was a flat curve while white cooked stage.at the end of the growth stage it was a three-peak curve.2. At flowering stage the diurnal change of net photosynthetic rate(Pn)in junzao-jujube was a typical double-peak curve,and presented obvious midday depression.The peaks were detected at 11:00am and 15:00pm;the first peak was higher than the second.The Pn and Cond was significantly positively correlated (r=0.890),the Cond was significantly positively correlated with Tr(r=0.67).The Cond was the direct factor which lead to the midday depression.3. In single environmental factors,the Pn of Junzao-Jujube was increased with PAR intensity rising until reached its saturation intensity; The Pn was growing with the increasing of CO2 concentration within a certain range.The LCP and LSP of junzao-jujube were 31.5μmol·m-2·s-1 and 1000μmol·m-2·s-1.The CCP was 59.5μmol·mol-14. The Pn of mid-position leaf of junzao-jujube was the highest,secondly in lower-position leaf.and lower in upper-position.The Pn of 4-7 position could stand for the photosynthetic capacity of bearing branch.distribution in the canopy,the upper bearing branch had higher Pn than central and lower bearing branch;The chlorophyll content of mid-position was stability;chlorophyll content and photosynthetic rate were positively correlated. 5. After we sprayed GA3,the Pn of junzao-jujube took on down trend but quickly recovered,what happed in the process needs our further study.We had found that sprayed ABA only had short impaction to the Pn,while sprayed GA3 and ABA mixed,the Pn and Cond decreased significantly.