The Physiology Effect Of CaCl₂ And GA₃ On Senescence Of Postharvest Jujube Fruits

The experiment was performed using the 'Dong'jujubes fruits to study the effect of CaCb and GAs on fruits qualities such as fresh rates, loss of water, Vc content, total soluble solids, fruit firmness, chromatism in senescence course. At the same time, fruits physiology and biochemistry changes such as respirations membrane permeability s MDA content SOD POD CAT and PPO activities also were affected. All above provided theoretical bases for improving on jujube store technology. The results of the study were as follows:1. The ' Dong' jujubes fruits qualities gradually dropped in postharvest senescence course, Vc contents firmness, total soluble solids, fresh rates dropped gradually; while loss of water and chromatism rose gradually. Therefore, we may divide the process into two phases. The first phase was front 30d, fruits qualities decreased slowly in this phase; the second phase was 30d later, fruits qualities dropped rapidly in this phase.2. The senescence and mature of the 'Dong' fruit went with the changes of SOD , POD and CAT activities, cell membrane permeability, MDA content and membrane lipid peroxidation.The process of membrane lipid peroxidation may be divided into two phases. The first 30d was the first phase, the process of membrane lipid peroxidation changes slowly in this phase; the second phase was 30d later, the process of membrane lipid peroxidation changes rapidly in this phase.3. CaCl2 and GA3 treatment may increase fresh rates, postpone the decreasing of Vc contents firmness and total soluble solids; restrain PPO activities , reduce flesh browning; restrain respiration, keep upper protective enzyme activities, reduce membrane lipid peroxidation, postpone senescence. The effect of GAs treatment was the best.4.In fruits senescence process, fruits senescence were controlled by the balance of IAA+ GAs and ABA. When IAA+ GAs dominated, fruits senescence were postponed; when ABA dominated, fruits senescence were accelerated. We may regulate the balance of endogenesis hormone to control the fruits senescence.