生物质炭对烤烟旺长期根系发育及光合特性的影响

旨在通过改变生物质炭在植烟土壤中的施入量,明确优质烤烟在生产环节的根系发育、叶片光合特性及地上和地下部分协调生长的生理指标,以改善东北植烟区烤烟品质较差的现状,于2015—2016年采用大田试验方式,设置6个处理(CK、T1、T2、T3、T4、T5),与当地常规施肥相比,各处理氮肥施入量均减少40%,分析不同生物质炭用量对烤烟旺长期根系生理指标与叶片光合生理指标的影响。结果表明:烤烟烟株在旺长期根系发育状况与光合生理指标、叶绿素含量、叶面积系数的状况是协调一致的;施用生物质炭2 400kg/hm~2的处理较对照提高根系活力177.8%、根系总面积91.35%、总根尖数100.9%、叶面积73.29%、叶绿素相对值(spad)57.68%、净光合速率77.32%、叶面积系数23.48%。生物质炭能够有效促进烤烟根系形态的生长发育,优化根系生理指标,并通过改善根系的发育,进而改善叶片光合生理特性及叶片发育指标,而生物质炭这种改良作用在T4(2 400kg/hm~2)达到顶峰。

Effects of Biochar on Root Development and Leaf Photosynthetic Characteristics of Flue-cured Tobacco in the Vigorous Growing Period

Roots are important for the nutrition absorption of flue-cured tobacco.In this study,by changing the amount of biochar in the soil,the effects of biochar on root system development,leaf photosynthetic characteristics,and physiological parameters of the coordinated growth of the aboveground and underground parts of flue-cured tabacco were investigated.A field experiment was carried out in 2015 and 2016,and there were six treatments,i.e.CK,T1,T2,T3,T4,and T5.Compared with the conventional fertilization,the nitrogen fertilizer application rate of each treatment was decreased by 40％.In the key growth period of flue-cured tobacco,root system growth characteristics and leaf photosynthetic characteristics were determined.The results showed that biochar application at 2 400 kg/hm2 increased root vigor by 177.8％,total root area by 91.35％,the total root tip number by 100.9％,leaf area by 73.29％,chlorophyll relative value by 57.68％,net photosynthetic rate by 77.32％,and leaf area coefficient by 23.48％,respectively.Biochar could effectively promote the growth and development of the root of flue-cured tobacco,optimize root physiological parameters,and improve leaf photosynthetic physiological and leaf development parameters through the improvement of root development,with the improvement effects of biochar reaching a peak in T4.