减弱UV-B辐射对低纬高原烤烟农艺性状的影响

Effect of Ultraviolet-B Radiation on the Agronomic Traits of Flue-Cured Tobacco at Low-Latitude Plateau in High Elevation Area

摘要: 为了解太阳UV-B辐射对云南省高海拔烤烟农艺和形态性状的影响，本研究选取云南高海拔烟区的宣威县(海拔1997 m)，大田种植烤烟品种云烟87，采用大棚覆盖不同厚度透明薄膜减弱UV-B辐射的方式，研究了相对当地自然环境75.04% (A1)、70.01% (A2)和30.02% (A3)的UV-B辐射强度对云烟87农艺性状的影响。结果显示：1) 随UV-B辐射强度降低，A1和A2处理下植株茎高、茎围与节间距等增大，说明适当强度的UV-B辐射可促进云烟87的生长。2) 下部叶(第7叶)对UV-B辐射的反应较中部叶(第12叶)敏感，A1和A2处理第7叶叶面积较大，各处理第12叶形状和面积差异不大，但A1和A2处理的LSM显着高于A3。随UV-B辐射减弱，叶片总厚度、栅栏组织、海绵组织和上表皮厚度逐渐下降。但下表皮厚度、栅栏组织、海绵组织厚度占总叶片厚度的比值、以及栅栏组织厚度/海绵组织厚度比值差异不大。A1和A2处理下表皮气孔长度和面积显著大于A3 (P < 0.05)，气孔宽度随UV-B辐射强度降低而上升，处理间差异不显著，A1和A2处理气孔密度、指数和表皮细胞密度略低于A3处理。

Abstract: In order to understand the effects of solar UV-B radiation in high-altitude Yunnan Province on agronomic traits and morphology characteristics, flue-cured tobacco cultivar Yunyan87 was selected and planted in field under 75.04% (A1), 70.01% (A2) and 30.02% (A3) of solar UV-B radiations by canopy coverage of different UV-B transparent films in Qvjing (1997 m above sea level), which lo-cates in low-latitude plateau area of Yunnan, and the resulting effects of reduced UV-B radiation on this cultivar were determined. The results showed that: 1) with deceasing of UV-B radiation intensity, larger stem length, stem girth and internodes length were observed under A1 and A2. The results indicated that an appropriate solar UV-B radiation intensity can promote the growth and developmental process of Yunyan87. 2) the 7th leaf in underneath of Yunyan87 plant was more sensitive in response to UV-B radiation than the 12^th leaf in middle part of plant. The size of the 7^th leaf in A1 and A2 were bigger than that in A3, but specific leaf mass (LSM) in the three treatments had no significant differences. However, the shape and area of the 12th leaf in the three treatments with in-distinct differences and LSM in A1 and A2 were significantly higher than that in A3. With reducing of UV-B radiation from A1 to A3, total leaf thickness, thicknesses of palisade tissue, spongy tissue and epicuticula were decreased gradually. But no significant differences were observed in abaxial epidermis thickness, ratios of palisade tissue/total leaf thickness, spongy tissue/total leaf thickness and palisade tissue/spongy tissue. Stomatal length and singal stomatal area of abaxial epidermis in A1 and A2 were significantly larger than that in A3 (P < 0.05), but stomatal wildth increased with UV-B radiation reducing without statistic variations. Stomatal densities, index and abaxial epider-mic cell densities in A1 and A2 were little lower than A3.