The Effect of Sun-shading and Increasing Ultraviolet Radiation on Growth and Quality in Flue-cured Tobacco
|School||Hunan Agricultural University|
|Course||Tobacco science and engineering technology|
|Keywords||flue-cured tobacco sun-shading ultraviolet radiation quality growing development|
Ecological environment is considered as the primary cause with idiomatical fragrance formation in flue-cured tobacco. Light circumstances is extremely close with distinguishing feature or quality of tobacco leaf in those main fit and optimum tobacco planting regions. This research was conducted with verities "K326", "HongDa" and "YunYan 87" as experimental materials. The advaneed analytic technology of high performanee liquid chromatography (HPLC) and gas chromatography (GC) were utilized to analyze the effect of sun-shading and increasing ultraviolet radiation on growth and quality in flue-cured tobacco. The main results were indieated as follows:(1) In 2008,we tracked and researched the growing development of "K326" in different sun-shading conditions to discover follows:Sun-shading influenced daily variation of light intensity and ultraviolet radiation intensity.under shading, maturing time of tobacco prolonged,length and breadth of leaf, the plant height and leaf area increased, the activitie of POD decreased,and the content of potassium increased.During the growing process, the content of chlorophyll and carotenoid firstly increased and then decreased gradually. low light intensity retarded the decomposition of chlorophyll and carotenoid. Under shading, the contents of nicotine and total nitrogen increased, and the contents of total sugar and reducing sugar decreased.(2) seedling of tobacco with different ultraviolet radiation was researched in 2009.Result demonstrates follows:under additional ultraviolet radiation, the content of chlorophyll decreased, but the ratio of chlorophyll a to chlorophyll b increased. The content of carotenoid presented increasing tendency with low dose of ultraviolet radiation. The volume of root,fresh weight of root and dry weight of tobacco plant decreased,but activity of root vigor and activity of SOD and POD increased observably with low dose of ultraviolet radiation. The restoring rate increased and restoring time reduced.(3) Potted planting tobacco with different ultraviolet radiation intensities was researched in ChangSha in 2009. Result indicated that under additional ultraviolet radiation, the agronomic trait changed tremendously, plant height, stem diameter, length and breadth of leaf decreased,and the decreasing tendency intensified along with ultraviolet radiation intensity raising.with the ultraviolet radiation intensity of 3.0 kJm-2d-1, activity of CAT and POD, activity of root vigor and content of nicotine increased, but with the ultraviolet radiation intensity of 8.0 kJm-2d-1, activity of CAT and POD, activity of root vigor and content of nicotine decresed relatively.With low intensity of ultraviolet radiation, the contents of major components of polyphenols and carotenoid increased, and compared with chlorogenic acids, the amplitude of rutin increased.The contents of organic acids increased,and the amplitudes of oxalic acid,malic acid,citric acid,myristic acid and oleic acid presented obviously. The tendency of response to the additional ultraviolet radiation between "K326" and "HongDa" is approximately consistent, but the response level showed discrepancy.(4) Field cultivation tobacco with different ultraviolet radiation intensities was researched in QuJing in 2009. Result indicated that under additional ultraviolet radiation, plant height,leaf area,stem diameter,distance of stem point, amount of root, separation angle of stem and leaf and dry matter accumulation of underground plant decreased. Growing development was influenced under additional ultraviolet radiation, and growth of tobacco was retarded in the prior period but maturing time speeded up in the later period. Under additional ultraviolet radiation, the contents of nicotine and total nitrogen decreased remarkably, the contents of total sugar and reducing sugar decreased,contents of potassium in upper leaf and middle leaf and contents of chlorine in upper leaf decreased.Under lower intensity of ultraviolet radiation,contents of rutin,β-carotene and polybasicorganic acids increased, contents of malic acid in "YunYan 87" increased, contents of malic acid in "K326" decreased slightly,and contents of oxalic acid and citric acid increased.