湖北海棠阶段转变的生理基础

Physiological basis of phasic change in Malus hupehensis (Panlp.) Rehd

In order to provide more evidences for the mechanism of phasic change 4-year old (mature phase) apomictic seedlings of crabapple 〔Malus hupehensis (Panlp.) Rehd.〕 were selected as trial material, and 1-year-old seedling and 4-year-old grafted plant developed from the adult-phase bud were used as contrasts of juvenile zone and adult zone of perennial seedlings respectively. The height-associated characteristics of leaf physiological indexes were investigated. The result showed that, based on the fresh weight of leaves, the amounts per unit of total soluble sugar, reducing sugar, soluble protein, total nucleic acid and RNA increased with leaf position height rising in mature seedling, on the contrary, the content of DNA decreased. Their contents at different leaf positions above the lowest flowering point remained at the same levels. The content of non\|reducing sugar of leaves did not vary with different leaf positions in mature seedling and grafted plant. Total nucleic acid content per unit of fresh leaf weight increased along with the leaf position height of seedling, it is due to the increasing of RNA content. The amounts per unit of total soluble sugar, reducing sugar, soluble protein, total nucleic acid and RNA could serve as markers to assess characterization of phasic change.