Physiological changes of leaves in response to cold in Phyllostachys propinqua

摘要

There are no previous records about planting bamboo in Changli, Hebei Province, north China. Since they were introduced in 2004, the propinquity bamboo (Phyllostachys propinqua McClure) has demonstrated good adaptability to the cold climate in Changli. The overwintering status of the bamboo and some of its physiological changes after the winter have been studied to ascertain the adaptability of the bamboo to the cold weather in Changli and to establish a firm basis for growing the plants in larger areas in northern China. The bamboo lived through the winter without any protection. The leaves of windward bamboos growing at various intervals have been studied for their viability and health after the winter. The changes in some physiological indices of the leaves were measured in the following spring. Results showed that the bamboo is partly green even at a temperature as low as -22.3℃ in Changli. During the winter, some leaves died and some partly died. Leaves are light in color and turn gradually to a dark green when the temperature increases in the following spring. As new leaves develop, the contents of chlorophyll and water and the ratio of free and bound water in the old leaves increase as does transpiration. At the same time the contents of free amino acid, proline, soluble sugar, malondialdehede (MDA), permeability of the membrane, superoxide dismutase (SOD) and peroxidase (POD) activities decrease. The direction of these physiological indices changes when the new leaves begin to sprout. The old leaves reduce their rate of photosynthesis, their blade functions decline gradually and the leaves fall off towards the middle of June. The cold wind affects the survival of bamboo leaves in winter, but has little effect on new leaves growing at the start of the following year. The results indicate that the propinquity bamboo can survive the winter in Changli quite well.