磷素对水稻根表红棕色铁膜的影响及营养效应  

Effect of Phosphorus on Reddish Brown Iron Plaque on Root Surface of Rice Seedlings and Their Nutritional Effects

作　　者：傅友强[1] 杨旭健[1] 吴道铭[1] 沈宏[1] 

机构地区：[1]华南农业大学资源环境学院,广州510642

出　　处：《中国农业科学》2014年第6期1072-1085,共14页Scientia Agricultura Sinica

基　　金：国家自然科学基金项目(31372125;31172026;31071847);高校博士点基金(20104404110016);广东省高层次人才项目(2010-412)

摘　　要：【目的】磷饥饿能明显诱导水稻根表红棕色铁膜的形成。然而,磷素是如何诱导水稻根表红棕色铁膜形成并不清楚。【方法】论文在水培条件下,对24个不同来源的传统水稻品种培养21 d后,分别进行缺磷和0.1 mmol·L-1 Fe2+处理,测定其根长、根表面积、根系干重、地上部干重及根表铁含量,从而筛选出根表铁膜含量较高的水稻品种"天优998",并以此为材料,设置不同养分元素缺乏试验(缺氮、缺磷、缺钾及其交互等8个处理)、分根试验(两边根系同时进行正常磷处理;一边根系缺磷处理,另一边根系正常供磷处理;两边根系同时进行缺磷处理)和不同磷铁比试验(磷浓度为0.0125—0.4 mmol·L-1;铁浓度为0.1—3.2 mmol·L-1,按磷铁比为1﹕1;1﹕3;1﹕5;1﹕8处理设计了4个小试验),测定了水稻根表铁膜浓度、根表无机磷浓度、根内无机磷浓度、根系和地上部磷、铁含量,探讨了磷素对根表红棕色铁膜形成及其营养效应。【结果】不同水稻品种根表铁膜浓度存在明显差异,24个水稻品种幼苗根表铁膜浓度范围为3.67—9.78 mg·g-1,水稻根表铁膜含量与根长、根表面积、根系干重、地上部干重呈显著的正相关。不同养分元素缺乏试验表明,水稻根表铁膜由红棕色铁膜和非红棕色铁膜组成,仅缺磷处理都能诱导水稻根表红棕色铁膜的形成,而缺氮和缺钾处理却不能。分根试验处理表明,缺磷处理根系侧并不能诱导正常供磷处理侧根系根表形成红棕色铁膜,根表红棕色铁膜形成主要受根表外源无机磷的影响,与根内无机磷无关。不同磷铁比试验表明,根表红棕色铁膜形成与根表磷铁比有关,根表DCB-Fe浓度与根系溶液中铁浓度有关;只有当磷铁比≤1﹕3时,根表才会形成明显的红棕色铁膜,随着磷铁比的降低,根表红棕色铁膜颜色加深;随着根系溶液中铁浓度的增加,根表DCB-Fe浓度逐渐增加,最大值为36.50 mg�[ Objective ] Phosphorus （P） deficiency could significantly induce the formation of reddish brown iron plaque on the surface of rice roots. However, it remains unclear how P induces the formation of reddish brown iron plaque on root surface. [Method] In this study, 24 rice varieties of different origins were used to measure the iron plaque on their root surface. Rice seedlings were firstly cultivated for 21 days hydroponically, and then submitted to P-deficient solution and 0.1 mrnol.L-1 Fe2solution, respectively. The parameters including root length, root surface area, root and shoot dry weight and content of iron plaque were determined after treatments. Based on the above parameters, a rice variety （Tianyou 998） was screened with higher amount of iron plaque. In the following experiments, effects of different nutrient deficiencies （N deficiency, P deficiency, K deficiency, and their interactive treatments, etc.）, root-split treatments （root system was divided into two parts, both two parts were treated with P supply treatments, one part was treated with P-deficient treatment, and the other was with P supply treatment, or both two parts were treated with P-deficient treatment） and different P/Fe treatments （1 ： 1, 1 ： 3, 1 ： 5, 1 ： 8） on the formation of iron plaque were examined with Tianyou 998 as materials. After treatments, contents of iron plaque, inorganic P content on root surface, root and shoot P or Fe uptake were determined to investigate the effect of P on iron plaque and their nutritional effects. [Result] Different rice varieties had various content of iron plaque. The content of iron plaque on root surface among 24 varieties ranged from 3.67 to 9.78 mg.g-1. The amount of iron plaque on root surface was correlated with root length, root surface area and rice biomass. Results from nutrient-deficient experiments indicated that iron plaque by DCB method consisted of reddish brown and non reddish brown iron plaque. Only P deficiency could induce the formation of reddish brow

关 键 词：磷素 水稻 红棕色铁膜 磷铁比 

分 类 号：X173[环境科学与工程—环境科学]