Physiological Characteristics Of Weeping Phenomenon And Its Simple Sequence Repeats Analysis In Weeping Peach (Prunus Persica Var. Pendula)

Weeping characteristic is a very usual variation in plants, but with very little physiological or genetic studies. Character segregated progenies of weeping peach (Prunus persica var. Pendula) were studied by using morphological, physiological and molecular marker methods, and the developmental characteristics of weeping branches and gene marker technique were disscussed. In this study we used SSR technology in the identification of weeping gene in peach and did integrative analysis in the distribution and content of lignin and gibberellin, the main results were submited as follows:1. Branch angle measured as the virtual angle was found a more reliable parameter in characterizing the tree shape in peach than the actual crotch angle measured at the base of the branch since the shape of the crown is more closely related to the former branch angle measurement. As the investigate on the standard and weeping tree form, the mean crotch angle is 52.5°and 52.0°, respectively; but in weeping form, the mean basal crotch angle and extended angle is 51.7°and 92.9°, respectively. That means the weeping trees grew downward when growing longer. Moreover, the angle of the root is related to the extended angle of the branch, the crotch angle of standard and weeping form is 78.3°and 42.5°, respectively, the roots of weeping peach also grow"downward". When the trees were grown upside down, the braches also grown down to the earth, suggesting that the growth direction is induced by gravity.2. Lignin is an important component of mechanical tissue and contributes to the supportive function of branches. Cross sections stained for lignin using phloroglycinol-HCl reagent suggests that the width of xylem in young shoot of standard form is 133% higher than that of weeping form, and the development of vascular bundles between upper and lower sides in weeping peach is not proportional. The lignin content in standard form was a little higher than in weeping form, and lignin content in lower side of weeping form is much lower than in upper side. The distribution of lignin results in the lower support ability of mechanical tissue in branches, and the deficiency of support ability results in the weeping of weeping peach's branches.