移栽期对湘西烤烟湘烟7号产质量的影响

为探明主要气象因子对湘西山地烤烟产质量的限制与影响,优化烤烟移栽期,通过连续3年烤烟主栽品种湘烟7号的不同移栽期大田试验,探索移栽期变化规律,研究日照、降水量及温度与烤烟产质量的关系。结果表明,香气质、余味与烤烟移栽期中等相关,香气量和产值与移栽期强相关;同时T1处理[4月12日(低海拔)、4月19日(中海拔)与4月26日(高海拔)]移栽的烤烟香气质、余味、香气量评吸得分值和产值最大,相比于其它4个处理的平均值增幅分别为6.16%±2.99%、19.39%±5.85%、5.38%±1.68%、19.37%±5.86%。简单相关分析表明,≥12℃有效积温、降水量、日照时数3种气象因子两两间均呈极显著正相关,且与多数产质量指标呈极显著相关。典型相关分析结果表明,产质量因子与气象因子间存在极显著的典型相关关系,烤烟移栽期主要影响降水量与≥12℃有效积温及香气量和产值的大小。主成分分析结果显示,第一主成分说明调节烤烟移栽期能改善气象因子与烤烟产质量,在效应上具有相似的特点;第二主成分说明烤烟移栽期影响气象因子与产质量上的主要差异是刺激性、杂气、产值、燃烧性、余味、≥12℃有效积温的变化。因此,从产质量上看,4月12日、4月19日与4月26日分别是湘西烟区低、中、高海拔地区湘烟7号的最佳移栽期。

外源表油菜素内酯和过氧化氢对低温处理后湘烟7号幼苗生理特性的影响

以烤烟品种湘烟7号为材料,经4℃处理4 d后连续喷施0.01 mg/L表油菜素内酯(EBR、T1)和340 mg/L过氧化氢(H_(2)O_(2)、T2)4 d,以进行低温处理后喷施蒸馏水的烟苗为低温处理对照(CK1),以未经低温处理喷施蒸馏水的烟苗为正常生长对照(CK2),测定烟草幼苗生物量、抗氧化酶(SOD、POD、CAT)活性、MDA含量、渗透调节物质及根系活力。结果表明:与CK2相比,湘烟7号烟苗经4℃低温处理后,根系活力及生物量降低,CAT活性、MDA、可溶性糖及脯氨酸含量升高,SOD、POD活性及可溶性蛋白含量无显著变化;与CK1相比,喷施EBR和H_(2)O_(2)的烟苗根系活力、根冠比、保护酶活性均明显提高,干物质量分别提高40%、20%,可溶性糖分别增加66.3%、51.3%,MDA含量分别降低37.8%、37.5%;低温处理后转入常温的第8天和第12天,喷施EBR、H_(2)O_(2)的处理与CK2相比,SOD活性、POD活性、可溶性糖、脯氨酸含量无显著差异,可溶性蛋白含量显著降低。恢复正常生长温度后,喷施外源EBR和H_(2)O_(2)均能加速烟苗生理指标恢复正常,其中以喷施EBR的效果更好。

Study on Harvest Maturity of Lower Tobacco Leaves of Xiangyan 7 Under Tobacco-Rice Rotation System

To clarify the suitable harvest maturity of Xiangyan 7 of the lower leaves of paddy-tobacco,the curing test of lower tobacco leaves with different maturities was carried out in Guiyang tobacco area of Hunan in China.The results showed that the SPAD value of fresh tobacco and proportion of normal group decreased,the proportion of mottle tobacco increased,the appearance quality of tobacco leaves became worse,the level of total sugar,reducing sugar,nicotine and reducing sugar/total sugar increased,and the total nitrogen/nicotine decreased with increased harvest maturity of lower tobacco leaves.It could cause lower smoking quality,lower proportion of high-class tobacco leaves and lower average price if the harvest of lower tobacco leaves was delayed.Therefore,the lower leaves of Xiangyan 7 in Guiyang tobacco area of Hunan should be harvested early.Suitable harvest maturity required light green leaf blade,light green midrib,and curl leaf margin.When the SPAD value of fresh tobacco was 26.26~30.33,it could be used as a reference for guiding the appropriate harvest maturity of lower paddy-tobacco leaves of Xiangyan 7.