【摘要】 通过人工气候室模拟低温条件,对49个供试品种进行耐寒性鉴定。可分为三级:第一级属耐寒性强的品种有4个,第二级属耐寒性中等的品种有37个,第三级属耐寒性差的品种8个。 综合生理测定的结果,耐寒品种均具有较高的可溶性糖含量,较高的组织汁液浓度,较高的组织束缚水含量,较低的电导率。同时,在叶片的形态结构上,组织排列比较紧密背面气孔数目较少;在内部的细胞亚显微构造上,随低温条件延长,叶内贮藏性淀粉粒逐渐分解,从而提高体内可溶性糖含量,提高组织汁液浓度,保护了各种细胞器的机能,维持细胞的正常生理活动。更多还原

【Abstract】 The experiment on identifying the cold-tolerance of 49 Guangdong sweet potato varieties was made in the artificial climate laboratory under imitating natural low temperature conditions, According to the level of cold-tolerance, the tested varieties could beclassified into 3 classes. The first class(4 varieties)with strong cold-tolerance grew well with green stems and leaves in the cold conditions, which could be used as the parents for breeding cold-tolerance varieties.The second class was medium cold-tolerunce (37 varieties). In most of them, the old leaves were damaged, changing the color from green to brown, or appearing black specks. But in some of them, a little damages might be found on the young leaves or at the bndlets. The third class (8 varieties) with weak cold-tolerance, the stems and the leaves as well as the budiets were damaged. And most of the leaves looked as if they were scalded and would died as soon as they were put in sunshine.The results in studying their physiological properties showed that the cold-tolerant varieties had relatively high contents of dissoluble sugar and tissue binding water, relatively high density of tissue fluid and low rate of electric conductivity. It was a found that in morphology the leaf constitution of strong cold-tolerant varieties was compact with less stomata on the back of the leaves The submicroscopic structure of leaf cells also showed that storable starch in the leaves gradually decomposed into dissoluble Sugar under low temperature conditions. These changes protected all kinds of cell structures from the damages caused by low temperatures, thus ensured the constitution of their cell organs and the normal physiological activities.更多还原