Impact of Heat-Shock Treatment on Yellowing of Pak Choy Leaves

Impact of Heat-Shock Treatment on Yellowing of

Pak Choy Leaves

WANG Xiang-yang;SHEN Lian-qing;YUAN Hai-na

【期刊名称】《农业科学学报（英文版）》

【年(卷),期】2004(003)006

【摘要】The physiological mechanism of maintaining the green colour of pak choy leaves (Brassica rapa var chinensis) with heat-shock treatment was studied. Chlorophyll in the outer leaves of pak choy degraded rapidly during storage at ambient temperature (20 ± 2℃), a slight yellow appeared. Heat-shock treatment (46- 50℃) had a mild effect on maintaining the green colour of outer leaves. Normal chlorophyll degradation was associated with a binding of chlorophyll with chlorophyll-binding-protein preceding chlorophyll breakdown.Heat-shock treatment was found to reduce the binding-capacity between chlorophyllbinding-protein and chlorophyll. In the chlorophyll degradation pathway, pheide dioxygenase was synthesized during leaf senescence which was considered to be a key enzyme in chlorophyll degradation. Activity of this enzyme was reduced following heat-shock treatment, which might explain the observed reduction in chlorophyll breakdown. Two groups of heat-shock proteins were detected in treated leaves, the first group containing proteins from 54KDa to 74 Kda, and the second group contained proteins from 15