生物炭对水稻秧苗生长及内源激素的影响

摘要

A super rice variety (Oryza sativa L.'Shennong 265') was cultivated with carpet seedling added different proportion biochar in plastic greenhouse in order to study to the impacts of biochar on rice seedling growth and endogenous hormones. Results showed that biochar significantly increased the cation exchange capacity and conductivity, reduced the bulk density, the improvement of soil aeration and moisture. Biochar significantly improved the growth ability of aboveground of rice (e.g. leaf age, leaf length, leaf width, plant height, stalk width and root-shoot ratio) and root (e.g. the total root length, root surface area, root volume, root average diameter, root tips and root forks) relative to the control. Meanwhile, with the increasing of application rate of biochar the endogenous hormones (e.g. IAA, GA, CTK) content in leaf, stalk and root increased at first and then decreased, and ABA content changed in the contrary trend. Correlation analysis showed that the rice endogenous IAA content had correlated positively and significantly with stalk width, dry weight and root-shoot ratio (p<0.05). The rice endogenous GA3 content had correlated positively and significantly with leaf width, stalk width and root tips, and leaf length, plant height, root cap ratio, the plant dry weight, root length, root volume, root surface area and root forks reached extremely and significantly level (p<0.01). The rice endogenous CTK content had correlated positively and significantly with leaf width , root tips (p<0.05), leaf length, plant height, the plant dry weight, root-shoot ratio, total root length, root volume, root surface area and root forks reached extremely and significantly level (p<0.01). On the contrary, the plant endogenous ABA content had significantly and negatively correlated with root average diameter (p<0.01).Comprehensive analysis showed that the suitable biochar application rates (30%-40%) were beneficial to improve the nutritional soil physical and chemical properties, and enhance the comprehensive quality.%以超级粳稻品种沈农265为试材,采用大棚旱育毯苗试验,在常规营养土中添加不同比例生物炭,研究生物炭对水稻秧苗生长及内源吲哚乙酸(IAA)、赤霉素(GA3)、细胞分裂素(CTK)和脱落酸(ABA)的影响.结果表明,添加生物炭明显增加了营养土中阳离子交换量和电导率,降低了容重,显著提升了通气和持水性能.与对照相比,生物炭可显著提高秧苗地上部(叶龄、叶长、叶宽、株高、假茎宽和根冠比)和根系(总根长、根表面积、根体积、根平均直径、根尖数和根分支数)生长能力.同时,随施炭水平的增加,叶片、假茎和根系中的内源激素(IAA、GA3、CTK)含量呈先升后降趋势,而ABA则相反.相关分析表明,水稻植株内源IAA含量与假茎宽、百株干重和根冠比呈显著正相关(p<0.05);植株内源GA3含量与叶宽、假茎宽和根尖数呈显著正相关,且与叶长、株高、根冠比、百株干重、根总长、根体积、根表面积和根分支数的相关性达极显著水平(p<0.01);植株内源CTK含量与叶宽和根尖数呈显著正相关(p<0.05),且与叶长、株高、百株干重、根冠比、总根长、根体积、根表面积和根分支数的相关性达极显著水平.相反,植株内源ABA含量与根平均直径呈极显著负相关(p<0.01).综合分析表明,适量添加生物炭有利于改善营养土理化性质,进而提高秧苗综合素质,其中以添加生物炭30%~40%效果最为明显.