断根和环割对烤烟叶光合特性及产量和质量的影响

Effects of root pruning and girdling on photosynthetic characteristics and yield and quality of flue–cured tobacco

以红花大金元烤烟品种为材料,研究了打顶后不同程度断根和环割对烤烟叶片厚度、叶面积、光合特性及产量和质量的影响。结果表明:下部叶采收后环割和两侧断根能促进鲜烟叶叶面积增加,较对照不环割、不断根分别增加18.01%和9.29%,叶片分别变薄7.20%和1.88%,显著提高了上部叶开片程度;烟叶SPAD值和净光合速率下降快,烟叶成熟落黄迅速;上中等烟叶比例分别增加6.73%和4.75%,烟叶均价分别提升11.12%和5.44%,经济效益显著提高;中部叶采收后环割,对上部叶叶面积和叶片厚度影响小,但可显著促进上部叶SPAD值和净光合速率的下降,促进上部叶提前落黄采烤,对烟叶产量和质量的影响较小;一侧断根可提高烟叶的抗逆性,抑制烟叶净光合速率下降,延缓烟叶采烤时间。下部叶采收后环割可作为促进中上部叶成熟落黄、提高烟叶产量和质量的一项技术措施。

Flue–cured tobacco variety Honghuadajinyuan were used as materials to study the effects of different degreesof root pruning and girdling on leaf thickness,leaf area,SPAD value,photosynthetic characteristics,yield and quality offlue–cured tobacco.The results showed that when root girdling and bilateral root pruning were conducted after theharvest of lower leaves,the leaf area of fresh leaves were increased by18.01%and9.29%respectively,compared to thecontrol with no root girdling and pruning;the blades were thinned by7.20%and1.88%respectively,which significantlyimproved the extension level of upper leaves;the SPAD value and net photosynthetic rate decreased rapidly and theleaves matured and turned yellow rapidly;the proportion of medium tobacco increased by6.73%and4.75%respectively,and the average price of tobacco was improved by11.12%and5.44%respectively,and the economic benefit wasimproved significantly.Root girdling after the harvest of middle leaves had little effect on upper leaf area and thickness,but significantly promoted the decrease of SPAD value and net photosynthetic rate of the upper leaves,promotedyellowing of the upper leaves,and had little effect on the yield and quality of tobacco.Root pruning on one sideimproved tobacco resistance,restrained decrease of tobacco net photosynthetic rate,delayed the tobacco harvest time.Itwas concluded that girdling after lower leaves harvesting can be used as a technical measure to promote the upper leavesyellowing and to improve the yield and quality of tobacco.