Study On The Dormancy Of Leeks And The Habit Of Low Temperature Growth In Winter Sheds

Chinese chives(Allium tuberosum Rottl.ex Spr), belongs to the lily family Allium, is a perennial plant, native to China. Winter protected cultivation of leek is closely related to low temperature growth characteristics. The paper taking 13 leek cultivars as materials, designed different temperature and hormone treatment for seed germination tests of leek, winter greenhouse cultivation experiment, studied the dormancy and germination characteristics of leek, the growth morphological differences under low temperature cultivation, the physiological index of vegetative nutrition tissues for low temperature resistance, yield of the harvest stubble, quality change’s regularity of leek, chive’s dormancy characteristics and physiological mechanisms of resistance to low temperature growth. The conclusions as follow:1 The optimum hormone concentration of leek seed germination was IAA 20 mg/1 and GA3 150mg/l.The optimum germination temperature was 17℃. The suitable germination temperature ranged from 14℃ to 23℃, the variety of NO.5 had the widest suitable germination temperature rang from 14℃ to 29℃. At high and low temperature inversion conditions, the leek seed germination was significantly higher at the low temperature (6℃) with hormones treatment subordinate.11 leek cultivars showed some regularity at different temperature. Leek growth rate express stage adaptation along with the temperature change cultivated in indoor artificial climate box. The optimum growth temperature was 20-30℃, but the plant growth was inhabited below 15℃ or above 35℃. Under plastic greenhouse cultivation in winter, Leek growth rate showed a positive correlation with the change of temperature. As the temperature decreases, the growth rate slowly. Plant growth was correlation with seed germination in temperature adaptability. The germination ability of dormant cultivars were weak.Un-dormant cultivars had high germination and good resistance to low temperature.2 Through the main agronomic characters tested, finded the roots and bulbs of underground are closed to the nature height an per plant weight of leek. In winter greenhouse cultivation of leek, all growth traits exhibited reduced as the temperature dropped; With growth period prolonged and temperature recovery gradually, root’s weight, bulb’s weight and thickness of the leek continued to decline, while the height, weight of per plant were increased. So roots, bulbs and sheath are the main place to store nutrients, the bulb and root were important factors to impact low temperature resistance of leek.the total yield of the cultivars No.l3(Jiuxing No.1), NO.5(Pengguan Fl), NO.3(Duokang Chives 11F1) were higher, at low temperature, the cultivars No.l3(Jiuxing No.1) and NO.1(Jiuxing No.10) had strong characteristics, they were suitable for winter cultivation in plastic greenhouse.3 Changes of water content of bulbs, roots and leaf sheaths of 6 stubbles in winter greenhouse, all showed the trend of "up-down-up", however, the opposite change trend of the soluble protein content and soluble sugar content was basically "drop-down-up". It expressed that growth of leeks under low temperature stress is the expendable growth, and leeks rely mainly on store nutrients of roots and bulbs to support plant growth, while under optimum temperature, photosynthesis of plants enhances, the protein content and sugar content of bulb and roots increased, and decreased water content, at high temperature, photosynthesis decreased, and less accumulation of multi-nutrient, water contence increased.Then leaf water content presented the trend "down-up-down-up ", the soluble protein and sugar content was "up-down-up-down". the blade is the assimilation organ, water content decreases under low temperatures, but the nutrient accumulation increases, it shows the flexibility towards low temperature, Therefore, changes of soluble protein and soluble sugar in plant bulbs and roots related to low temperature growth. The accumulation of nutrition in the root and bulb are import for the production and cultivation.4 As for cultivation via shed in winter, dormant cultivars have high chlorophyll content, with dark green leaves, while non-dormant cultivars have low chlorophyll content, with leaf green or light green leaves. The VC content in blade of leek significantly higher, followed by leaf sheaths, the VC content in greenhouse grown is less than the open field grown; the chlorophyll content closely related to leeks VC content, that high chlorophyll content, VC content is high. The crude fiber content of leaf sheathes was higher than blades. The content of crude fiber in leaf sheaths and blades lower the same. Under low temperature stress, crude fiber has low content, as temperatures rising next, photosynthesis enhancing, crude fiber accumulation increased. So, cultivation in winter greenhouse; the soluble protein content and soluble sugar content of leaf sheaths bulbs, and roots decreased, chlorophyll content of leaf increased, energy nutrients VC content decreased, crude fiber decreased show ecological adaptability to low-temperature growth, they can be acted as reference indexs for low temperature growth characterization.