澳洲坚果生理落果期果柄离区形态学结构及细胞壁相关酶活性分析OA

The morphological structure and cell wall-related enzyme activity in carpopodium ab-scission zone of normal and dropped macadamia nuts in the early physiological nut-drop period were compared for theoretical basis on physiological research of nut and the formulation of nut preserva-tion control measures in production.Paraffin section was used to observe the morphological structure of carpopodium abscission zone of macadamia.The activity of cellulase and polygalacturonase en-zymes in carpopodium abscission zone of macadamia on 30 d,40 d and 50 d after flowering were tested by biochemical micromethod and their differences were analyzed.The results showed that the epidermal cells of the normal carpopodium were tightly arranged without the abscission zone,while the carpopodium of dropped nuts had obvious abscission zone.The abscission zone was composed of 2-3 large and elliptical cells that were loosely arranged,with larger cell gap and higher lignifica-tion degree than the surrounding tissue cells.During the early physiological nut-drop period,the ac-tivity of cellulase and polygalacturonase in carpopodium of dropped nuts were significantly higher than those in normal macadamia nuts.The results shows that the lignification degree of carpopodium abscission zone and the activity change of cell wall-related enzyme such as cellulase and polygalactu-ronase are the important factors causing the early physiological nut drop of macadamia.