Study On Cultivation Physiology And Ecology Of Phoebe Bournei

Phoebe bournei is a commercially important woody species which called Nanmu, one of precious wood which has color brilliancy, high commercial value and artistic, and is an economic and social strategic resources. It was once abundant in the Southern of China, owing to deforestation and intensive grazing, this species is under second-class national protection in China. In this paper, distribution area and the corresponding climate characteristics were studied in order to provide suitable cultivation areas, Provenance zone allocation also carried out base on populations’ genetic diversity for Seed deployment, response to light regimes and drought stress also be studied in order to resolve the problems existed in the production practice.(1) Distribution and climate characteristics were analyzed by field investigation and literature retrieval. Results showed that the Phoebe bournei mainly distributed between24.18-30.29N,106.2-121.5E and40-1220mH, the most appropriate mean annual temperature ranged from16.45-20.55℃, the highest and the lowest mean month temperature ranged from26.56-30.04℃and4.88-10.55℃respectively. The warm index and cold index was140.42-184.91℃and-1.96-0.23℃respectively. The precipitation and PET means1505.65mm and979.57mm. The distribution area belongs to warm and moist habitat condition. The most suitable distribution area localed in the24-30N,110-123E, including the northern area of Guangxi and Guangdong, south-central Hunan, northeast of Jiangxi and Zhejiang, in central asia north of Fujian. Suitable area including the northern of Zhejiang and Hunan, southern of Anhui, Hubei,Yunnan,Guangdong, Guangxi and Fujian, the south area of annual mean temperature minimum line is potential distribution area and north is not suitable areas.(2) Using inter-simple sequence repeat (ISSR) markers to compare six populations’genetic diversity, the Polymorphic bands Percent ranged from13.46%to67.31%, and the order from largest to smallest is FJSX> GDSX> JXLN> FJZH> ZJKH> HNYX. There exist some extent genetic differentiation among six populations, the Shannon index (Ⅰ) and the Nei’index (H) ranged from0.09to0.35and0.06to0.24, respectively. The genetic diversity from high to low is FJSX>JXLN>GDSX>FJZH>ZJKH>HNYX. The existed genes flow among populations (Nm=0.1), but the value is very small. The genetic diversity (Dst) is0.20, and the genetic diversity is main among populations. Based on the Neis unbiased genetic distance, the whole natural range might be obviously divided into North provenance zone (ZJKH&FJSX), Middle provenance zone (FJZH&HNYX) and South provenance zone (JXLN&GDSX).(3) Two-year-old Phoebe containing seedlings were subjected to water stress and recovery treatment to study their physiological and biochemical responses. Physiological and biochemical indices did not change when seedlings were subjected to mild water stress (<15days of water withholding). As drought stress intensified (>20days of water withholding), malondialdehyde (MDA) and electrolyte leakage (EL) increased, and chlorophyll (Chl) and soluble protein (SP) decreased, indicating an increased oxidative stress induced by water deficit. Enhanced activities of superoxide dismutase (SOD) and peroxidase (POX), accumulation of free proline (Pro) and total soluble sugar (TSS) contribute to plant protection against the oxidative stress. However, SOD and POX decreased when seedlings were subjected to an extended drought. These results demonstrate that seedlings could enhance their ability to mitigate water stress effects by up-regulating antioxidant system and osmotic adjustment, but these two protective mechanisms were limited when seedlings were subjected to moderate and severe water stress. The threshold of water deficit to P. bournei seedlings is15-20days, and permanent damage will be induced if water status is not improved before this threshold.(4) The seedlings growth, biomass accumulation and physiological and biochemical responses were be studied in response to different light regimes (100%of full sunlight, L100;50%of full sunlight, L50;20%of full sunlight, L20). After two years of adaptation, the results showed that seedlings’height and diameter were largest under L50, the seedlings that under moderate shade conditions (L50), total biomass increased with increasing light intensity, but decreased if light intensity beyond a threshold. Seedling quality index, antioxidant enzyme activity and maximum net photosynthetic have the highest value under50%of the light treatments.