摘要
[目的]探明不同遮荫方式对雪茄茄衣鲜烟叶生长和光合生理特性的影响.[方法]对遮阳网颜色(绿色、黑色、白色)、遮光率(40％、60％、80％)和遮荫时间(移栽后20、25、30 d)进行正交L9(34)设计,测定遮荫后烟株的农艺性状、叶绿素含量、荧光参数和光合生理指标,分析与光合相关基因的表达情况,并对测定的指标进行显著性分析和极差分析.[结果]①遮阳网颜色是影响农艺性状的主要因素,而影响光合生理的因素排序为遮光率＞遮阳网颜色＞遮荫时间.②遮荫后白色遮阳网促进了茄衣烟叶生长;总叶绿素含量随遮光率的增加而增加;实际光化学效率(ΦPSⅡ)、叶绿素潜在活性(Fv/Fo)、光化学淬灭系数(qP)和最大光化学效率(Fv/Fm)在高遮光率下显著提升,但非光化学淬灭系数(qN)显著下降;净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均下降,在80％遮光率下达到最小,而胞间CO2浓度(Ci)在80％遮光率下显著增加;编码光系统Ⅱ中捕光复合物叶绿素a/b结合蛋白4.2的基因(Lhcb4.2)和编码光系统Ⅱ中反应中心蛋白CP47的基因(psbB)表达量在80％遮光率下显著增加,编码光系统Ⅱ中捕光复合物叶绿素a/b结合蛋白6的基因(Lhcb6)在60％遮光率下显著增加,编码光系统Ⅱ中D2蛋白的基因(psbD)在80％遮光率下表达量比不遮荫处理低,而1,5-二磷酸核酮糖羧化/加氧酶小亚基基因(rbcS)和编码光系统Ⅱ中D1蛋白的基因(psbA)无明显变化.[结论]遮荫处理改变了光质和光强,影响了编码光合作用有关蛋白的基因表达,从而影响烟叶的光合作用,遮荫后不同程度地加快了叶绿素的积累和光合作用效率,且在80％遮光率处理下影响最大.
Abstract
[Objective]The present study aimed to investigate the effects of different shading methods on the growth and photosynthetic physio-logical characteristics of fresh cigar wrapper leaves.[Method]The experiment conducted an orthogonal L9(34)design on the color(green,black,white),shading rate(40％,60％,80％),and shading time(20,25,30 days after transplantation)of the shading net,measured the ag-ronomic traits,chlorophyll content,fluorescence parameters,and photosynthetic physiological indicators of shaded tobacco plants,analyzed the expression of genes related to photosynthesis,and performed significance and range analysis on the measured indicators.[Result](i)Shading net color was the main factor affecting agronomic traits,and the ranking of factors affecting photosynthetic indicators was shading rate＞shad-ing net color＞shading time.(ii)After shading,the white shading net promoted the growth of cigar wrapper tobacco leaves;The total chloro-phyll content of fresh tobacco leaves increased with the increase of shading rate;The actual photosynthetic efficiency(ΦPS Ⅱ),chlorophyll potential activity(Fv/Fo),photochemical quenching coefficient(qP),and maximum photochemical efficiency(Fv/Fm)significantly in-creased under high shading,but the non-photochemical quenching coefficient(qN)significantly decreased;The net photosynthetic rate(Pn),stomatal conductance(Gs),and transpiration rate(Tr)all decreased,reaching their minimum at 80％shading,while the intercellular CO2 concentration(Ci)significantly increased at 80％shading;The expression levels of the gene encoding the light harvesting complex chlorophyll a/b binding protein 4.2(Lhcb4.2)and the gene encoding the reaction center protein CP47(psbB)in Light System Ⅱ significantly increased under 80％shading.The gene encoding the light harvesting complex chlorophyll a/b binding protein 6(Lhcb6)in Light System Ⅱ signifi-cantly increased under 60％shading.The gene encoding the D2 protein in Light System Ⅱ(psbD)was expressed lower under 80％shading than under non-shading,However,there were no significant changes in ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit gene(rbcS)and the gene encoding D1 protein in photosystem Ⅱ(psbA).[Conclusion]The shading treatment alters light quality and intensity,af-fecting the expression of genes encoding proteins related to photosynthesis,thereby affecting the photosynthesis of tobacco leaves.After shad-ing,the accumulation of chlorophyll and the efficiency of photosynthesis are accelerated to varying degrees,and the effect is the greatest under 80％shading rate treatment.
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