Influences Of Stand Type On Constitutive Resistance In Chinese Pine (Pinus Tabulaeformis )

In order to probe the influence of forest stand types on constitutive resistance of Chinese pine (Pinus tabulaeformis), the Chinese pine pure forest and Prunus armeniaca-Chinese pine mixed forest in natural and pine caterpillar (Dendrolinus punctatus tabulaeformis Tsai et Liu) were investigated. The contents of 6 biochemical substances (protein, soluble sugar, reducing sugar, crude fat, tannin and total phenol) in Chinese pine needles of different forest types were measured with physiological and biochemical methods. The influence of the contents of biochemical substances of Chinese pine and forest stand type on the growth and development of pine caterpillar were analyzed by feeding pine caterpillar one generation with Chinese pine needles of different forest types. The main results are as follows.(1)The pine caterpillar larva population parameters were strongly affected by feeding on Chinese pine needles of differential forest stand types. The pine caterpillar development duration was longer, body and pupa weight were lighter, feeding and feces amount were less, food consumption and usage and pupation rate more reduced, mortality more increased and fecundity more declined by feeding on Chinese pine needles from mixed forest than that from pure forest. The results proved that the insect-resistance was much more enhancement in mixed forest than that in pure forest.(2)The preliminary experiments on nutrient substance in pure forest and mixed forest needles of different time indicated that the changes of protein contents in two kinds of forests in May to July proved consistent, while the contents of soluble sugar and reducing sugar varied. In early May, there were highest protein contents in both pure forest and mixed forest needles, lowest contents of soluble sugar in pure forest needles and reducing sugar in mixed forest needles. There were higher protein and soluble sugar contents in mixed forest needles than that in pure forest. In early June, the contents of protein and reducing sugar in Chinese pine needles of pure forest declined, whereas the contents of soluble sugar increased. In contrast, the contents of protein and soluble sugar in Chinese pine needles of cross forest declined, whereas the contents of reducing sugar increased to the highest. In early July, the contents of all 3 substances in Chinese pine needles of pure forest and mixed forest decreased. The results indicated that stand type could strongly affect nutrients substance content in Chinese pine needle.(3)The preliminary experiments on secondary substance in pure forest and mixed forest needles of different time indicated that there were fluctuations in the secondary substances contents in both two kinds of forests in May to July. In early May, there were higher crude fat and tannin contents and lower total phenol contents in needles of cross forest than that of pure forest. In early June, the contents of tannin, total phenol and crude fat in needles of pure forest increased. In contrast the contents of total phenol in needles of cross forest increased, whereas the contents of crude fat and tannin declined at different degree. The contents of tannin, total phenol and crude fat in needles of pure forest were all proved to be higher than that of cross forest. In early July, the contents of tannin, total phenol and crude fat in needles of pure forest decreased. In contrast the tannin and total phenol contents in needles of cross forest of crude fat decreased, whereas the contents of crude fat increased. And there were higher crude fat and total phenol contents in needles of mixed forest. The results indicated that the secondary substances content in pine needle were affected by forest stand.