Research On Seedling-raising Technique By Improving Temperature And Fill-in Light In The Curing Barn

Seedling cultivation was the premise to increase the yield and quality of tobacco leaves and the main factor to improve tobacco growers'income as well as the foundation of high quality cigarette manufacturing. In Hunan tobacco-growing areas, the temperature and light were lower in seedling periods so that it needed longer times. Combined with seedling technique research achievements on other plants, adequately utilizes the existing tobacco facilities, seedling-raising technique by improving temperature and fill-in light in the curing barn. As the purpose to cultivate high quality seedlings, provide base of theory and technical support to improve tobacco seedling technique and improving the tobacco seedling environment and improve the quality of tobacco seedlings. Among them, the main results were as follows:1The seedling growth periods had certain differences under different light compensation. To extend the light time could shorten the period of cotyledons to euphylla cross, and the best treatment was24h light. At the time of euphylla cross, to improve the environmental temperature and add red with blue light can obviously shorten seedling growth period and accumulate more dry matter. Then9treatments performed smaller differences at the period of euphylla cross to6leaves. During seedling stages, the growth stages were extended on3treatments that moved to shed, but the overall trend performed that happening speed of leaves gradually close to CK as time pushing in. In the whole seedling stages, the treatments of A2B2C1, A3B1C1, A2B2C1, A3B1C2shorten40-50days.2In the aspect of agronomic characters, the largest stem height was A3B1C1at the period of euphylla cross and the smallest was A1B2C1, showed that extending could improving stem height growth significantly, followed by A2B2C1, A3B1C2, CK, the treatments of A2BlCland A3B2C1were worst. The stem circumference at seedling stages was highest for CK (1.91cm) and followed by A3B1C2, A3B1C1, A2B2C1. Leaf area was bigger for A2B2C1,A3B1C1, A3B1C2and twice as large as CK.3The whole plant fresh weight were higher for A3B2C1and A3B1C1at seedling stages, and the highest whole plant dry weight was A2B2C1, followed by A3B1C2and CK. For root fresh and dry weight, A1B1C1and A3B1C1had higher fresh weight as well as A2B2C1had higher dry weight. For stem fresh and dry weight, the highest was A3B2C1, because of lower temperature for CK, the metabolic and growth speed were slower. For leaf fresh and dry weight, the highest fresh weight was A3B2C1, the highest dry weight was A2B2C1. In the whole seedling stages, dry matter was higher for A3B1C2and A2B2C1, also with normal metabolism and better than CK.4The physiological and chemical indexes of root activity, nitrate reductase activity, invertase activity, pigment content and MDA content had larger differences on different treatments. To synthesize all the biochemical indexes, the best treatments were A2B2C1and A3B1C2. Combined with the production practice and improving the overall quality of tobacco seedlings, it's better to provide24hours and22-25℃as well as red and blue light in curing barn for the conditions that taking the process in a shed, then moved to the shed at the time of euphylla cross. For the areas that not had the shed establishment, it's better to provide18hours as well as red and blue light in order to utilize the tobacco production elements maximize.