光质对立体浮盘培育烟苗叶片光合特性及根系生长的影响

Effects of light qualities on the photosynthetic responses of tobacco seedling and root growth in a float system

为研究光质对立体浮盘培育烟苗叶绿体色素、光合响应和根系发育的影响,试验设置白光(对照)、红光、蓝光和LED光4个处理.结果表明:与其他光质比较,蓝光光质下烟苗叶绿素a含量显著(P＜0.05)提高16.13％～28.57％、叶绿素b显著提高30.00％～36.84％,此外,类胡萝卜素含量比红光光质下显著提高18.18％;不同光质条件下烟苗叶片最大净光合速率(Pmax)的大小关系为蓝光＞白光＞ LED光＞红光,且蓝光光质下烟苗光饱和点最高;红蓝光质下,烟苗根系长度、根系表面积、根系平均直径和根系体积均显著(P＜0.05)增加,以蓝光下烟苗根系发育最好,其烟苗4叶1心时根系长度达98.11 cm、根系表面积22.78 cm2、根系平均直径0.74 mm和根系体积0.42 cm3.本研究结果表明,采用蓝光光质更适用于烤烟立体育苗,有利于培育壮苗.

Light qualities of white (CK),red (RL),blue (BL) and LED (LL) were set up in this study in order to demonstrate effects of light qualities on the chloroplast pigment,light response and root development for tobacco seedlings in a three-dimensional float system.Results showed that BL significantly (P＜0.05) improved the content of chlorophyll a of tobacco seedling leaves by 16.13％-28.57％ and improved the content of chlorophyll b by 30.00％-36.84％ compared with other light qualities;otherwise,BL significantly (P＜0.05) increased the carotenoid content by 18.18％ compared with RL.For the maximum net photosynthetic rate (Pmax) of tobacco leaf,the relationship of different light qualities displayed as BL＞CK＞ LL＞ RL; moreover,the light saturation point (LSP) was maximum under the condition of BL compared with other light qualities.BL and RL significantly (P＜0.05) increased the root length,root surface area,average root diameter and root volume of the tobacco seedlings,especially in BL.As for the tobacco seedlings in BL,at the stage of 4 leaves and 1 heart,the root length,root surface area,root average diameter and root volume were 98.11 cm,22.78 cm2,0.74 mm and 0.42 cm3 respectively.The preliminary analysis indicated that the blue light quality may be more suitable for flue-cured tobacco seedlings in the three-dimensional float system.