Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Chine → 2010 → Characteristics of Photosynthesis and Water Use of Dominant Tree Species in Two Typical Forests and Related Factors in the Semiarid Region of Loess Plateau, China

Graduate School,Chinese Academy of Sciences (2010)

Characteristics of Photosynthesis and Water Use of Dominant Tree Species in Two Typical Forests and Related Factors in the Semiarid Region of Loess Plateau, China

Wang Yi Long

Titre : Characteristics of Photosynthesis and Water Use of Dominant Tree Species in Two Typical Forests and Related Factors in the Semiarid Region of Loess Plateau, China

Auteur : Wang Yi Long

Grade : Doctoral Dissertation 2010

Université : Graduate School, Chinese Academy of Sciences

Résumé partiel
Very fragile ecosystem of semi-arid areas of the Loess Plateau. Serious soil erosion and drought are two major ecological problems facing the region. Sustainable recovery of the vegetation is the fundamental way to regional ecological security in the area of ??governance and water resources protection. Contradiction revegetation and water shortage in the ecological restoration of the area, the semi-arid areas of the Loess Plateau two typical stand Liaodong oak natural secondary forest and locust plantation in Yan’an City Road, Forest Area, the application of LI-6400 portable photosynthesis system on two typical stand species leaf photosynthesis, transpiration characteristics and its influencing factors were studied. TDP sap flow measurement system and automatic weather station positioning observation of a single the wooden water consumption characteristics of two typical stand species and corresponding environmental factors ; systematic analysis of the two typical stand each species trunk sapwood liquid circulation The influencing factors of the amount of density ; estimate the 2008 growing season, two typical stand transpiration. The main results are as follows : 1, the two main species of Typical Forests locust and oak Photosynthetic diurnal growing season sunny bimodal or single peak curve, two of the main tree species are obvious \The reasons for the two species \The impact of the two species \Locust is higher than the maximum photosynthetic capacity the Liaodong oak maximum photosynthetic capacity, but the average daily photosynthetic rate was less than the average photosynthetic rate of the the Liaodong oak growing season day. The two species leaf net photosynthetic rate and stomatal conductance, intercellular CO2 concentration, photosynthetically active radiation, air temperature, CO2 concentration, air water vapor pressure difference and the relative humidity of the air very significant or significant related. The dominant factors that affect the net photosynthetic rate of the two species is a physiological factor (Gs and Ci), ecological factors may indirectly affect leaf photosynthesis of trees through the leaves of the two species Gs and Ci. Light response curve analysis showed that aggravated soil drought, the blade carbon sequestration capacity of the two species and the ability to take advantage of the low light and bright light reduced. 2 showed a single peak in the diurnal variation of the growing season, locust and oak leaf transpiration rate curve or irregular multimodal shaped curve. Seasonal differences in the process of leaf transpiration rate of the two species may be associated with the biological characteristics of the two different species, it may be due to differences of the growing season in different periods of the ecological factors. Different periods during the growing season, the two species leaf transpiration rate and stomatal conductance, photosynthetic active radiation, air temperature, relative humidity and air water vapor pressure difference has a very significant or significant relationship. The growing season in different periods of physiological and ecological factors affect the two species leaf transpiration rate. 3, locust plantations and oak natural secondary forest species sapwood flow flux density diurnal variation on sunny days with daily solar radiation and water vapor pressure difference similar trend. Two typical stand species (locust, oak and wild apricot) of different diameter trees there are significant differences in the sapwood flow flux density. All sorts of tree growing season average the sapwood flow flux density with the corresponding DBH There was no significant correlation between the two major Typical Forests species the sapwood flow flux density may be affected by the constraints of multiple physiological and ecological factors

Mots clés : Loess Plateau Typical Forests Photosynthetic Transpiration Water Consumption Semi-arid areas

Présentation (Dissertationtopic)

Page publiée le 6 mai 2013, mise à jour le 4 mai 2018