Studies Of Semi-lethal Temperature And Physiological Changes Under Cold Stress On Two Kinds Of Gesneriaceae Flowers

Owing to having plenty of advantages including colourful flowers, unusual leaves, compact plant shape, reproducing and planting easily, strong ability resist to drought and barren surrounding, Gesneria family plants had prodigiouss development potential. But physiology research on cold resistance in gesneria family plants was still scarce. In the paper, two gesneria family plants—Aeschynanthus radicans and Columnea gloriosa, as test materials, their semi-lethal temperature(LT50) were researched, Furthermore, physiological and biochemistry change in 4 different low temperature stress were researched in-depth in period of time from post-treated to recover normal temperature. And feasible index on cold resistance was analyzed combination with test results. Which provided a theory and test foundation on cultivation research in Hangzhou of gesneria family plants.These test results were indicated as follows:1. Relative electric conductivity change of leaf was feasible index in physiology on low temperature stress in the two Gesneria family plants. Low temperature below 6℃and 0℃can bring on cold damage of leaf obviously in Aeschynanthus radicans and Columnea gloriosa respectively, and their membrane permeability increase with processing time prolong.2. LT50 of Aeschynanthus radicans and Columnea gloriosa could be calculate out by REC combination with Logistic Equation under different low temperature. Through counting, LT50 was determined between 8.1℃and 10.1℃in Aeschynanthus radicans, or between -3.34℃and 1.81℃in Columnea gloriosa. The temperature index will be very important to verify cold resistance of Aeschynanthus radicans and Columnea gloriosa. In order to facilitate calculate, the processing time could take 24-36h and should not be used less than 24h.3.Under different low temperatures stress:chlorophyll content take on downtrend in both Aeschynanthus radicans and Columnea gloriosa with processing time prolong; Leaf MDA content in Aeschynanthus radicans showed a trend from decline to rising with processing time prolong under low temperature, but that in Columnea gloriosa showed a trend from rising a little,decline to rising. Furthermore, leaf MDA content of both plants reached top after 10 days under low temperature, and decline along with temerature rising; Superoxide dismutase (SOD) activity showed a trend from rising to decline, reached the lowest point after 10 days, and gradualness recovered with temperature return. Chlorophyll content, MDA content and SOD activity of significant difference between the low temperature, could be used as important index on cold resistance.