Study On Effects Of Growth Regulators On The Growth And Physiological Characteristics Of Pistacia Chinensis

Pistacia chinensis is one of the important woody oil plants and urban greening trees which widely cultivated in northern China in recent years. However, Pistacia chinensis fear the cold, in northern winter, Pistacia chinensis often sprout and even death, and this limit Pistacia chinensis planted and promotion in the northern areas and. In this study, with Pistacia chinensis as materials, which were treated by foliar spray method, we studied that the effects of different concentrations (0, 200mg/L ,500 mg/L, 800 mg/L, and 1500 mg/L) PP333 and CCC treatment on the growth characteristics, physiological characteristics, photosynthetic and physiological characteristics and the cold resistance characteristics in winter. Trying to seek an appropriate cultural measure, in order to protect Pistacia chinensis smoothly grown in winter, and this has a very important significance for seedling and cultivation of Pistacia chinensis in the northern areas in the future. The major results as follows:(1) With the increasing concentration of the growth regulators, the relative annual growth of Pistacia chinensis was decreasing. The stem of Pistacia chinensis was increasing. The ratio of fresh weight and dry weight, the ratio of root to shoot, soluble protein and soluble sugar content firstly increased and then decreased. Among them, 800 mg/L PP333 and 500mg/L CCC treatment effectively enhanced the ability of metabolism of Pistacia chinensis, promoted the growth of root, could significantly increase the content of soluble sugar and promote much more soluble sugar to transfer to the roots, could significantly increase the content of soluble protein and at the same time could ease the degradation of soluble protein.(2) With the increasing concentration of the growth regulators, the content of malonal dehyde level(MDA) firstly increased and then decreased and increased at last. The superoxide dismutase(SOD) and peorxidase(POD) activity firstly increased and then decreased. The indoleacetic acid oxidase (IAAO) activity was increasing. Among them, 800 mg/L PP333 and 500mg/L CCC treatment could significantly improve SOD and POD activities and effectively reduced MDA content.(3)With the increasing concentration of the growth regulators, the ratio of palisade tissue thickness and sponge tissue thickness, the content of chlorophyll and carotenoid, the net photosynthetic rate(Pn), ratio of variable to maximum fluorescence(Fv/Fm), potential photochemical efficiency(Fv/Fo) of Pistacia chinensis firstly increased and then decreased. Among them, 800 mg/L PP333 and 500mg/L CCC treatment could significantly increase the ratio of palisade tissue thickness and sponge tissue thickness and the content of chlorophyll and carotenoid, increased the net photosynthetic rate of Pistacia chinensis, enhanced the ability of photosynthesis of Pistacia chinensis. This study also preliminary obtained the mechanism that the growth regulators increase the net photosynthetic rate of nursery stock and ensure the efficient photosynthesis of nursery stock: with 800 mg/L PP333 and 500mg/L CCC treatment, the increase of thickness ratio of palisade tissue and sponge tissue and content of chlorophyll improved the ability of capture and absorption light energy of leaves, the increase of openness degree and actinity of PS II reaction centers ensured the efficient transfer of light energy and reduced the heat dissipation of energy at the same time, thus significantly improved the net photosynthetic rate of Pistacia chinensis.(4) With the increasing concentration of the growth regulators, the relative conductivity in branches of Pistacia chinensis firstly decreased and then increased. The survival rate live through the winter firstly increased and then decreased. Among them, 800 mg/L PP333 and 500mg/L CCC treatment could significantly reduce the relative conductivity in branches of Pistacia chinensis, could effectively ease the role of the electrolyte leakage, thus increased the cold tolerance of Pistacia chinensis, increased the survival rate live through the winter.This study suggested that with the 800 mg /L PP333 and 500 mg/L CCC treatment, the variations of Pistacia chinensis in growth, the substances of osmoregulation, physiological characteristics and photosynthetic and physiological characteristics was the material basis of the enhancing cold tolerance of Pistacia chinensis. The cold tolerance of Pistacia chinensis had been enhanced was because of the variations of Pistacia chinensis in growth, the substances of osmoregulation, physiological characteristics and photosynthetic and physiological characteristics with the 800 mg /L PP333 and 500 mg/L CCC treatment.