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【目的】有机磷为土壤磷库的重要组成部分,发掘作物吸收利用土壤有机磷的能力和机理有利于充分利用土壤磷素资源。本研究系统地研究植酸态有机磷条件下野生大麦根系形态变化和根系生理反应特征,以揭示磷高效基因型大麦有机磷利用生理机制。【方法】以磷高效基因型大麦(IS-22-25、IS-22-30)和低效基因型大麦(IS-07-07)为试验材料,植酸钠为有机磷源进行水培试验。设置5个植酸钠浓度(0.1、0.2、0.3、0.4、0.5mmol/L),使用根系扫描仪分析其根长、根表面积、根体积等形态特征,并测定根系与根系分泌的酸性磷酸酶、植酸酶活性等生理特征差异及变化趋势。【结果】随有机磷浓度降低,磷高效基因型野生大麦总根长、总表面积和总体积呈增加趋势。低有机磷浓度下,磷高效基因型大麦总根长较正常有机磷浓度(0.4mmol/L)高了139.7%～146.0%,直径D<0.16 mm的根长高了156.8%～161.5%,且磷高效基因型总根长较低效基因型高8.6%～60.4%。低有机磷浓度下,磷高效基因型根系各参数均显著高于低效基因型。随着有机磷浓度降低,磷高效基因型根总表面积提高了83.5%～117.5%,较低效基因型高14.0%～46.4%;根总体积提高了80.7%～119.3%,较低效基因型高19.6%～150.0%。随着有机磷浓度升高,磷高效基因型根系及其分泌酸性磷酸酶和植酸酶活性显著降低。低有机磷浓度下,磷高效基因型根系酸性磷酸酶和植酸酶活性增加了163.3%～172.2%和98.6%～121.2%,较低效基因型高14.4%～41.2%和23.1%～37.2%;磷高效基因型根系分泌酸性磷酸酶和植酸酶活性增加了157.8%～193.4%和172.4%～183.4%,较低效基因型高20.2%～45.7%和24.7%～51.4%。【结论】在低浓度有机磷胁迫下,磷高效基因型通过良好的根系形态,有效扩大了根系对水分和养分的接触空间,为磷高效基因型的快速生长和磷素吸收提供了条件;同时,低浓度有机磷胁迫诱导了根系及其分泌的酸性磷酸酶、植酸酶活性增强,提高了介质环境中磷素的生物有效性,对有机磷的吸收利用表现出明显优势,是其高效吸收利用有机磷的机制之一。
【Objective】 Organophosphorus is an important part of soil phosphorus pool. To explore the ability and mechanism of crops to absorb and utilize soil organic phosphorus is beneficial to make full use of soil phosphorus resources. In this study, we systematically studied the morphological changes of root morphology and root physiological responses of wild barley grown in acid phytic phosphorous to reveal the physiological mechanism of organic phosphorus utilization in P efficient genotypes of barley. 【Method】 Phosphorus-efficient genotypic barley (IS-22-25, IS-22-30) and inefficient genotype barley (IS-07-07) were used as experimental material, and sodium phytate as organic phosphorus source for hydroponic culture . Five sodium phytate concentrations (0.1, 0.2, 0.3, 0.4 and 0.5 mmol / L) were set up. The root length, root surface area and root volume were analyzed by root scanner. The acid phosphatase , Phytase activity and other physiological characteristics differences and trends. 【Result】 With the decrease of organic phosphorus concentration, total root length, total surface area and total volume of P efficient genotypes increased. Under the condition of low concentration of organic phosphorus, the total root length of barley with P efficient genotype was 139.7% ~ 146.0% higher than that of normal organophosphorus concentration (0.4mmol / L), and the root length of D & lt; 0.16 mm was 156.8% ~ 161.5% The total root length of high efficient genotypes of phosphorus was 8.6% -60.4% higher than that of lower genotypes. Under the low concentration of organic phosphorus, the parameters of roots with high P genotype were significantly higher than those with low genotypes. With the decrease of organic phosphorus concentration, the total root surface area of high efficient genotypes increased by 83.5% -117.5%, that of lower genotypes by 14.0% -46.4%, and that of total genotypes increased by 80.7% -119.3%. The lower genotype High 19.6% ~ 150.0%. With the increase of the concentration of organic phosphorus, the activities of P-efficient genotype roots and their secretion of acid phosphatase and phytase decreased significantly. Under the low organic phosphorus concentration, the activities of acid phosphatase and phytase increased by 163.3% ~ 172.2% and 98.6% ~ 121.2%, while the low efficiency genotypes increased by 14.4% ~ 41.2% and 23.1% ~ 37.2% ; Phosphorus-efficient genotypes increased 157.8% -193. 4% and 172.4% -183.4% of acid-excreting and phytase activities of root exudates and 20.2% -45.7% and 24.7% -51.4% of those of less-efficient genotypes. 【Conclusion】 Under the condition of low concentration of organic phosphorus, the efficient genotype of phosphorus could effectively enlarge the contact space between root and water and nutrients, which provided the conditions for the rapid growth and phosphorus uptake of phosphorus-efficient genotypes. At the same time, , Low concentrations of organic phosphorus stress induced the root system and its secretion of acid phosphatase, phytase activity increased, increasing the bioavailability of phosphorus in the media environment, the absorption and utilization of organic phosphorus showed obvious advantages, is its efficient absorption One of the mechanisms that make use of organic phosphorus.