生物炭对东北冷凉区水稻秧苗根系形态建成与解剖结构的影响

在黑龙江省早春水稻旱育苗背景下,研究了稻田土壤育苗基质中添加生物炭对秧苗根系形态建成与解剖结构的影响,以明确生物炭在东北冷凉地区水稻生产上的应用潜力和价值。以东北稻田土壤为育苗基质,添加0、5.0%、10.0%、15.0%、20.0%(w/w)的生物炭,进行保护地旱育水稻秧苗。出苗后30 d测定秧苗根系形态建成和解剖结构等性状,分析生物炭对水稻秧苗根系发育的影响。结果表明,在稻田土壤育苗基质中添加5.0%生物炭时,水稻秧苗根系长度、根系表面积和根系体积等明显增加;生物炭添加量为10.0%时,各项根系形态指标达到最高值;生物炭添加量超过10.0%时,根系形态指标下降。根长、根表面积和根体积增加的原因主要是细根增加。同时,添加5.0%生物炭时,根半径、根截面积、根表皮厚度、根皮层厚度、皮层腔面积、根导管数量及导管面积等性状指标也相应增加。生物炭添加量为5.0%~10.0%时,根解剖结构各项性状指标达到最大值。当生物炭添加量超过10.0%时,根系解剖结构性状指标也有下降趋势。根系增粗主要源于根表皮及皮层发育良好。在东北冷凉地区进行保护地水稻旱育苗,基质中添加适量生物炭(5.0%~10.0%)有利于秧苗根系的伸长及增粗,形成发达根系,提高秧苗素质。

Effect of Biochar on Root Morphogenesis and Anatomical Structure of Rice Cultivated in Cold Region of Northeast China

To explore potential and practical application value of biochar in rice production in the cold region of Northeast China, we added 0-20.0% (w/w) biochar in rice nursery substrate of paddy soil and studied the root morphogenesis and anatomical structure of rice at 30 days after seed germination, The treatment of 5.0% biochar significantly increased the root length, root surface area and root volume, with the maximum value for all the root morphological indexes in the treatment of 10.0% biochar. When the biochar added more than 10.0%, the root morphological indexes started to decrease. It was indicated that the increase of root length, root surface area and root volume was the consequence of producing more fine roots. Meanwhile, when 5.0% biochar added in the rice nursery substrate, root epidermis thickness, cortex thickness, sclerenchyma tissue, number of vessels, sectional area of vessels, cortex cavity area, sectional area of whole root and root radius increased in comparison with those of control. In the treatment of 5.0%-10.0% biochar addition, all the indexes of anatomical structure of root reached the maximum. When the biochar added more than 10.0%, all the indexes of anatomical structure of root had a descending trend. It was revealed that the well-developed root epidermis and cortex were the main reason of promoting enlargement of roots when a moderate amount of biochar was added in the rice nursery substrate. Taken together, we conclude that the proper addition of 5.0%-10.0% (w/w) biochar is advantageous to the elongation, enlargement and formation of well-developed root system ,resulting in improved quality of rice seedlings in the dry rice-nursery of protected area when the paddy soil is used as the nursery substrate in the cold region of Northeast China.