不同水分和土壤处理对糙毛以礼草苗期根系构型和根鞘形成的影响

doi:10.11686/cyxb2019278

摘要/Abstract

摘要： 为了探究水分和土壤对糙毛以礼草苗期根系构型和根鞘形成的影响,采用未灭菌和灭菌的沙土培养糙毛以礼草,分别设置田间持水量的10%、20%、30%、40%和50%水分梯度,测定不同水分和土壤处理条件下糙毛以礼草的根系构型参数和根鞘重,结果表明:1)在未灭菌土壤培养条件下,糙毛以礼草苗期的根系与土壤微生物互利共生,高水分显著影响了根系交叉数和分支数的增加(P<0.05);土壤灭菌培养条件下,这种关系遭到破坏,根系总根体积在40%~50%水分梯度下显著高于其他水分梯度(P<0.05),平均直径在40%水分梯度下最高(P<0.05),分支数在20%和50%水分梯度最高(P<0.05),链接数和根尖数在20%~50%水分梯度下显著增大(P<0.05),总根表面积在50%水分梯度下最高(P<0.05)。土壤灭菌后,微生物群体变化,土壤灭菌培养条件下的根系形态指标较未灭菌土壤培养条件下增大(P<0.05),分别为:20%水分梯度下的根系总根长和分支数,20%~50%水分梯度下的根系链接数和根尖数,40%水分梯度下的根系总根表面积和平均直径,40%~50%水分梯度下的根系总根体积。2)不同水分和土壤处理下糙毛以礼草苗期根系拓扑指数接近于1,根系分支模式接近鱼尾形分支,更适宜在地下资源贫瘠的环境中生长。在20%和30%水分条件下,糙毛以礼草保持了很好的根系构型,修正拓扑指数(q_b)和分形维数(FD)显著高于其他水分梯度(P<0.05)。糙毛以礼草苗期根系初生根和次生根生长过程中生物量分配的不同影响了根系在土壤中的功能,根系在土壤中的伸长拓展(总根长、总根表面积、链接数和分支数)大于固定渗透(平均根系直径)对根系构型的影响。3)水分和土壤处理对根鞘的形成无交互影响(P>0.05),糙毛以礼草苗期根鞘形成的影响因素为:水分>土壤>FD>q_b>根系固定渗透能力。随着田间持水量的升高,糙毛以礼草根鞘重呈现先增后减的趋势,未灭菌土壤和灭菌土壤中的根鞘重分别在20%~30%、30%水分梯度时最大,q_b、FD和根系固定渗透能力显著正向影响根鞘(P<0.05)。

关键词: 糙毛以礼草, 苗期, 根系构型, 根鞘

Abstract: In order to explore the influence of water content and the sterilized soil on the root architecture and rhizosheath formation of Kengyilia hirsuta at the seedling stage, five water supply levels (10%, 20%, 30%, 40% and 50% of field water capacity) were watered in sterilized and unsterilized soil to cultivate K. hirsuta. Several parameters for root architecture and rhizosheath weight were measured under different treatment conditions. The experimental results turn as follows. 1) The symbiotic relationship between K. hirsuta root system and soil microorganisms was found and the high water supply levels significantly increased root crossing numbers and branch numbers in the unsterilized soil (P<0.05). However, the symbiotic relationship was destroyed in the sterilization soil. The total root volume between levels of 40%-50%, the root average diameter under levels of 40%, the branch numbers under levels of 20% and 50%, the number of links and the number of root tips under the water levels of 20%-50%, the total root surface area under the water level of 50% were significantly higher than under 10% level in the sterilization soil (P<0.05). After soil sterilization the microbial community changed and the root morphology index significantly increased compared under the condition of unsterilized soil, such as the total root length and root branch in the 20% level, the number of links and the number of root tips in 20%, 30%, 40% and 50% levels, the total root surface area, the root diameter in the 40% level and the total root volume between in 40% and 50% levels, all differed. 2) Under the different water and soil treatment, the topological index of the root of K. hirsuta at the seedling stage was close to 1. The root branching pattern was close to fishtail branching, which is more suitable to grow in the poor soil. The root architecture of K. hirsuta was optimum in the 20% and 30% levels where the topological index (q_b) and fractal dimension (FD) were significantly higher than other water levels (P<0.05). The function of root system in soil was affected by the difference of biomass distribution between primary root and secondary root, and the elongation and extension ability of roots in the soil (total root length, total root surface area, number of links and number of branches) affected more root architecture than the fixed permeability (root average diameter). 3) There was no interaction effect on rhizosheath formation between the water supply and soil treatment (P>0.05), the factors with different influence degrees to the formation of rhizosheath of K. hirsuta at the seedling stage: water>soil>FD>q_b> fixed permeability. With the increase of water supply levels, the rhizosheath weight increased first and then decreased. The rhizosheath weight was maximum in the unsterilized soil of 20% and 30% field water capacity and in the sterilized soil of 30% field water capacity. q_b, FD and the fixed permeability have significantly positive effects on rhizosheath formation (P<0.05).

Key words: Kengyilia hirsuta, seedling stage, root configuration, rhizosheath

陈有军, 董全民, 周青平. 不同水分和土壤处理对糙毛以礼草苗期根系构型和根鞘形成的影响[J]. 草业学报, 2020, 29(3): 60-69.

CHEN You-jun, DONG Quan-min, ZHOU Qing-ping. The impact of different soil moisture and sterilization treatments on root architecture and rhizosheath formation of Kengyilia hirsuta at the seedling stage[J]. Acta Prataculturae Sinica, 2020, 29(3): 60-69.

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