Studies On The Photosynthesis In Different Type’s Tobacco And The Activity Of Protective Enzymes After Topping In Flue-cured Tobacco

The experiment were carried out to study the photosynthesis and the biological characteristics in the seedbed and the field growth period with14varieties of three types tobacco (flue-cured tobacco, sun-cured tobacco and burly tobacco), and to study the activity of protective enzymes after topping in flue-cured tobacco male sterile lines and their maintainer lines. The results are as follows:The sun-cured tobacco varieties’growth period of seedling stage are shortest, and the flue-cured tobacco varieties are shorter, while the burley tobacco varieties are long. The fourth’s leaf length of sun-cured tobacco is longest among the three types of tobacco. And the fourth’s leaf width of flue-cured tobacco is widest among the three types of tobacco. The chlorophyll content of flue-cured tobacco varieties is higher, while the sun-cured tobacco and burley tobacco’s chlorophyll content is lower. All varieties of tobacco seedlings’ chlorophyll content are dropped in March.The differences of the photosynthetic characteristics were small among three types tobacco but big among different varieties. The net photosynthetic rate was significantly correlation to the intercellular CO2concentration, transpiration rate and stomata conductance. The fresh weight of root cap ratio of different types tobacco seedlings were as following: burley tobacco> sun-cured tobacco> flue-cured tobacco, the dry weight of root cap ratio were as following: burley tobacco> sun-cured tobacco> flue-cured tobacco, and the ratio of dry weight to fresh weight of tobacco seedlings displayed burley tobacco> flue-cured tobacco> sun-cured tobacco.Sun-cured tobacco varieties have the shortest field growth period, flue-cured tobacco varieties range middle, burley tobacco varieties have the longest. In rosette stage and strengtrly growing stage, the net photosynthetic rate size order is that: sun-cured tobacco> flue-cured tobacco> burley tobacco, and in budding stage and mature stage, the net photosynthetic rate size order is burley tobacco> flue-cured tobacco> sun-cured tobacco. The intercellular CO2concentration was very significantly negative correlation to the net photosynthetic rate, stomata conductance and transpiration rate, the net photosynthetic rate was very significantly correlation with stomata conductance and transpiration rate, and the stomata conductance was also very significantly correlation with transpiration rate. The highest dry matter weight of roots, stems, leaves and plants is burley tobacco varieties, flue-cured tobacco is second, and sun-cured tobacco is the least. There are big different about the agronomic characters among the different types tobacco, the largest plant height and stem pitch is sun-cured tobacco varieties, flue-cured tobacco is second, burley tobacco is the smallest, the largest stem surround height and different parts leaf length and width is burley tobacco, flue-cured tobacco is second, sun-cured tobacco burley tobacco is the smallest.The net photosynthetic rate of no topping sterile lines is drop gradually, and the falling range is big. The intact maintainer lines, the topping sterile lines and the maintainer lines all slightly rose first then got down, did no topping maintainer lines is the second smallest, and the amplitude reduction of topping sterile lines and maintainer lines were the smallest. The highest intercellular CO2concentration is no topping sterile lines. The largest stomata conductance is no topping maintainer lines, the second is the topping sterile lines and maintainer lines, the smallest one is no topping sterile lines; The fastest transpiration rate is the topping sterile lines and maintainer lines, the second is no topping maintainer lines, and the slowest one is no topping sterile lines. The activity of SOD, CAT, POD of Flue-cured tobacco leaf were all going dowm before the first young capsule stage.In the first young capsule stage, the size order of the activity of the three kinds of enzyme was following as:no topping maintainer lines is the highest, the topping sterile lines and maintainer lines is better, no topping maintainer lines is the lowest, the declines time points of MDA content of Flue-cured tobacco is before the first young capsule stage, and the size order for performance, not the position of the department are the highest, and the other processing varieties MDA content order size is differed. The Physiological characteristicsof MDA, were very significant negative correlation with SOD, CATand POD, and SOD was very significant correlation with CAT and POD, CAT was significantly related to POD.