Studies On The Relationship Between Polyamine, Abscisic Acid And Heat Tolerance In Tomato

The optimal temperature for tomato growth is 20癈 to 25 癈, but the ambient temperature often reaches 35癈, even up to 40 癈. High temperature is one of the most important factors limiting quality and yield in tomato production. Studies on the mechanism of heat -tolerance in tomato are of great significance for breeding heat -tolerance variety and improving cultivation technology. The popurse of the present research emphasised on illustrating the relationships between ABA and polyamines and heat -tolerance, and offering base for developing high efficient, reliable evaluation ways to heat -tolerance of tomato and for the molecular biochemistry research.The present experiments, choosing heat -tolerant varieties '258', '259', '260', 'Sa' and heat -sensitive varieties 'Zhongshu No.5', 'Zhongshu No.6' as test materials, measured their polyamine and ABA levels at seedling and blooming stage at 25/20 癈, 33/25癈, 38/28癈(d/n), and researched the relationships between polyamine , ABA and heat -tolerance. At the same time, The present experiments researched effects of abscisic acid on the polyamines, ABA levels and the percentages pollen germination of these varieties. The present experiments measured the photosynthesis and percentage of pollen germination, and researched the relationships between heat -tolerance and them.1. Heat -sensitive varieties have maximum levels of spm and spd at 33/25癈, and have, the lowest levels at 38/28癈(d/n) at seedling and blooming stage. But heat -tolerant varieties reach maximum levels at 38/28癈(d/n). Their contents of heat -sensitive varieties are higher than that of heat -tolerant varieties at 25/20癈and 33/25 癈, but the later higher than the former at 38/28癈.With the changes of temperature, there aren't any regularity on the changes of put at seedling and blooming stage.2. The contents of ABA of all varieties are more and more higher with increasing temperature. At 25/20 癈, the content is no obvious difference between heat-tolerant varieties and sensitive- tolerant varieties. But, the contents of heat -tolerant varietiesare higher than that of heat -sensitive varieties at 33/25 癈 and 38/28癈.3. After pre-treatment with exogenous ABA, the contents of polyamines and ABA of all varieties increase under different temperatures. But, exogenous ABA can't make regularity of polyamines and ABA change with the changes of temperature.4. With increasing temperature, the capacitys of pollen germination of all varieties are decreased. But, decreased degrees of heat -tolerant varieties are lower than that of heat -sensitive varieties. These results indicate high temperature decrease pollen germination, but the percentages of heat- tolerant varieties are higher than that of heat -sensitive varieties under high temperature.Exogenous abscisic acid can enhance percentages of pollen germination of all varieties under different temperatures, but the percentages of heat-tolerant varieties are still higher than that of heat-sensitive varieties under high temperature.5. With increasing temperature, the photosynthesises rate of all varieties are decreased, but the decreased extents of heat-tolerant varieties are lower than that of heat-sensitive varieties.