果胶酶和纤维素酶在桃果实成熟和絮败中的作用

Role of Pectolytic Enzymes and Cellulase during Ripening and Woolly Breakdown in Peaches

测定了果胶酶和纤维素酶在桃果实软化和絮败过程中的活性 ,分析了贮前加温和中途加温的酶学效应。果实软化的启动似乎与PE、PG和纤维素酶活性的上升有关。endo PG和纤维素酶活性与果实絮败程度之间呈显著负相关 (r =- 0 .94 0 8,r =- 0 .92 34)。低温胁迫引起桃果实冷害絮败的本质是细胞壁果胶质的降解过程受阻。果胶质降解过程除了受到果胶酶的直接控制之外 ,还受到纤维素酶的重要影响。中途加温或贮前加温减轻冷害的原因在于避免了低温胁迫对endo PG和纤维素酶造成不可逆的伤害 ,从而保证了果胶质降解过程的正常进行。

Activities of pectolytic enzymes and cellulase in peaches〔 Prunus persica( L.)Batsch cv.Baifeng〕were determined during softening and development of woolly breakdown.Enzymatic response to pre warming and intermittent warming was also analyzed.Start of fruit softening seemed to be connected with the activity increase in PE,PG and cellulase.However,the level of PE and PG activities was not significantly related with the fruit firmness.Both endo PG and cellulase activities were significantly negative correlated with the degree of woolly breakdown ( r=-0.9408 ,r= -0.9234). The essential aspect of chilling injury known as woolly breakdown induced by low tem perature stress was the abnormal degradation of cell wall pectin,which was not only controlled directly by pectolytic enzymes but also influenced largely by cellulase.Alleviating chilling injury with the treatment of pre warming or intermittent warming was responsible for the prevention from irreversible damage to endo PG and cellulase from low temperature stress and thus guaranteeing the normal process of pectin degradation.