Effects Of Low Temperature And Weak Light On Photosynthetic Characteristics And Physiological Of Potato

Potato is the world important food crop. National Ministry of Agriculture has already made southern winter cultivated region an important place for potato's development, and in south, low temperature and weak light circumstance is the key factor which limits potato's growing.7 regular potato type,2 Hunan district type,1 type of wild potato were employed in this study, which design an evaluating indicator that is defined by light and respond in weak light stress. In this research, photosynthesis, chlorophyll content, the ratio of a/b of chlorophyll and content of MDA were measured under optimal temperature at 20/15℃and intensity of light at 200μmol m-2 s-1,sub-optimal temperature at 10/8℃and intensity of light at 200μmol m-2 s-1, low temperature at 5/5℃and intensity of light at 200μmol m-2 s-1, optimal temperature at 20/15℃and intensity of light at 50μmol m-2 s-1, sub-optimal temperature at 10/8℃and intensity of light at 50μmol m-2 s-1, low temperature at 5/5℃and intensity of light at 50μmol m-2 s-1, and discussed a high practical method of measuring of low temperature and weak light stress of potato, so as to select a type that has comparatively a higher resistance of weak light, low temperature and sensitivity. The results are as follows:1._Under a circumstance of different temperature:The Pn of the cultivars of Potato increased at the beginning then decreased following the SPR. The transpiration rate were increased along with the rising of light intensity, while the leaf conductance leaves of intercellular CO2 concentration in leaves were decreased along with the rising of light intensity.The water use efficiency rise almost linearly at first and then had slightly ecreasing rend with the increasing of light intensity. Under a circumstance of optimal temperature, Zhong 3, Zhong 5 and Jingshan had a Pnmax, and comparing to other types, it has a high ability of photosynthesis(19μmol CO2 m-2 s-1).2._Under a circumstance of optimal temperature:Sub-optimal temperature and low temperature are two kinds of circumstance that can affect the light saturation point and light compensation point to go down. Under a circumstance of low temperature, most types' Pn already cannot be measured. Under a circumstance of sub-optimal temperature:Series of Kexing (K1,K3,K4)'s Pn only reduced for 5% comparing to optimal temperature, Jingshan's Pnmax under sub-optimal temperature reduced for 50% comparing to optimal temperature(average25.8%).3._Under a circumstance of low temperature:Pn of F, Zhong 3, Xiang 1 is way more than other types, the other types' Pn already cannot be measured.All Chlorophyll a/b ratio reduced, the content of MDA increased all in cultivars of Potato。4._Under a circumstance of low temperature and weak light, Chlorophyll a/b ratio reduced, the content of MDA increased. Zhong 5 and Jingshan Can resist weak light under optimal temperature. Jingshan can make good use of light under optimal temperature, but it cannot resist low temperature, which can be called as a weak light resistable material but sensitive to low temperature. F, Zhong3, Xiang 1 can resist low temperature. F can maintain a high level of ability to resist low temperature and weak light. Comparing to other types, F is a low temperature and weak light resistable material.