Evaluation On The Heat Resistance Of Different Genotypes In Longiflorum Hybrids

Heat resistance in Lilium indicates the ability of withstanding and adapting high temperature. It's a complicated problem of physiology and biochemistry. Lilium always maintains water balance in its body by changing the morphological, physiological and biochemical state in high temperature environment.Using 20 Lilium longiflorum genotypes as materials, the regularity of morphological, physiological and biochemical variation in different genotypes was studied in the experiment, and heat resistance assessment indexes were screened. The results could be summarized as follows.1. The heat killing time at 50 was longest at the temperature of 38,which was 136.7 minutes. Cell membrane thermostability of Lilium longiflorum was best at this time. Therefore, the temperature of 38癈 is the best temperature of heat acclimation.2.Among the indices determined at normal temperature, significant or very significant differences in palisade parenchyma thickness, sponge parenchyma thickness, palisade parenchyma/sponge parenchyma ratio, leaf thickness, and stomata density existed among genotypes. After dealing with the temperature of 38 for 2 days, differences were observed for the physiological and biochemical indices. Bound water content , bound water/free water ratio, transpiration rate, CAT activity, SOD activity were increased; While free water content, free water content, cell membrane thermostability and soluble protein content were decreased.3. Under high temperature stress, chlorophyll content and MDA content did not expressed relationship with head formation, andcould not be used as the heat resistance indices of Lilium longiflorum.4. The results indicated that palisade parenchyma thickness, palisade parenchyma/sponge parenchyma ratio, leaf thickness, stomata density, protoplast density, relative water content, bound water content, bound water/free water, proline content, cell membrane thermostability, transpiration rate, soluble protein content, CAT activity, SOD activity had a positive correlation with whereas sponge parenchyma thickness had a negative correlation with heat-resistance. The system of the heat resistance assessment indices of Lilium longiflorum could be established by the fifteen indices.5. By comprehensive evaluation, the order of heat resistance among Lilium longiflorum genotypes was O2-28 > N2-6 > Ql-2 > M> O > K2-7 > Kl-4 > N > Nl-1 > Q > M2-8 > Fl > O1-13 > O- > O2-10 > Ul-2 > M2-9 > Ml-10 > Pl-1 > White Forest.