植物根系分泌物与根际营养关系评述

根系分泌物（ｒｏｏｔ ｅｘｕｄａｔｅｓ,ＲＥ）主要有粘胶、外酶、有机酸、糖、酚及各种氨基酸。不同营养基因型的植物,ＲＥ级分明显不同,存在养分和环境胁迫时,植物通过增加粘胶、酶及某些有机酸的分泌量以适应变化的环境。ＲＥ也是植物改善根际营养环境的重要手段。ＲＥ可改善土壤物理结构,促进矿物风化、提高土壤ＣＥＣ,影响土壤ｐＨ、土壤矿物表面吸附性能及土壤生物学性质。ＲＥ还存化根际土壤养分,促进植物对养分吸收     

根系分泌物的化感作用及其对土壤微生物的影响

总结了根分泌化感物质的种类及其化感效应,分析了生物和非生物因素与根系分泌化感物质之间的关系。此外,根系分泌化感物质的研究手段对于所取得的研究结果至关重要,其中根分泌物收集系统是收集根分泌化感物质的常用而可行的方法之一。对于根分泌化感物质的分离鉴定技术有多种,可根据需要选择适宜的分离方法。还列举了一些作物根分泌的化感物质对根际微生物产生的影响,阐明了根分泌的化感物质所起的重要化感作用。根分泌物化感作用的研究已成为土壤生态学领域的热点与前沿课题,自然条件下原位收集鉴定植物根系分泌物中的化感物质等诸多问题是该领域今后的研究重点。     

植物根系分泌物与根际微生物交互作用机制研究进展

根际是受植物根系影响最为强烈的微域环境,是植物和土壤交流的桥梁。根系能通过调控根系分泌物的种类和数量影响根际微生物的种群结构和多样性,根际微生物通过改变根际土壤特性影响根系的分泌作用,进而影响植物的生长发育过程。因此,很有必要对这些研究进展进行梳理,提出未来该领域的研究重点。本文以1999～2022年中国知网（CNKI）和Web of Science核心数据库为文献来源,对根系分泌物与根际微生物互作相关的64篇论文进行分析。总结了近年来根系分泌物和根际微生物互作的最新研究成果,重点介绍了根系分泌物对根际微生物种类、数量和分布的影响,环境胁迫对根系分泌物和根际微生物的影响,以及根际微生物对植物生长的影响。基于此,我们对该领域未来的研究方向进行了展望。深入理解根系分泌物和根际微生物之间复杂的互作关系及其机理,对揭示根际微生态调控过程、土壤微生物组功能、促进农作物增产等方面具有重要的意义。     

根系分泌物与土传病害的关系研究进展

根系分泌物是植物-土壤-病原微生物相互作用的桥梁,是决定病原菌-作物关系的关键生态因子,影响着土传病害的发生与发展.本文阐述了根系分泌物的定义、分类及产生机理;重点从根系分泌物的化感自毒效应,根系分泌物诱导根际微生物群落,根系分泌物影响病原菌丰度,根系分泌物影响根际土壤环境4个方面阐述了根系分泌物与土传病害的关系;并从...     

根系分泌物

概述了根系分泌物的产生,收集与分析及其影响因素和根系分泌物组分。阐明了根系分泌物与根际土壤微生物相互关系。     

根系分泌物抑制连作障碍线虫病的根际调控机制及其应用

作物长期连作极易出现连作障碍(再生病害),本文围绕因传统耕作模式和种植习惯而诱发的新疆棉花、黑龙江大豆、河南花生、山东设施蔬菜、两广香蕉等连作障碍问题,对全国连作现象进行系统分析,发现全国连作现象普遍。按照耕地面积将连作障碍划分为五个等级,其中华北三省和东北的黑龙江省连作障碍等级最高,且各省连作现象均以大田经济作物为主。以香蕉、大豆(大田经济作物)、黄瓜(设施园艺作物)和三七(中草药)为代表,比对最低产量和正常产量在连作年份的变化,表明连作障碍发生规律成抛物线式,防控连作障碍需找到问题关键时期。单一根系分泌物介导的微生物多样性降低、病原菌富集,植物寄生线虫危害和土壤弱化是导致连作障碍的主要原因,其中线虫对植物的侵染危害作为土传病害是防治连作障碍中最难解决的问题之一,尤其是在设施蔬菜上。线虫在长期进化过程中形成了具有识别、寻找和侵染寄主的生物学功能,而不同植物根系分泌物对线虫发育和对宿主的识别侵染能力有不同的调控作用。针对根系分泌物–线虫互作为诱因的线虫病害,深入探讨易感作物和抗性/非寄主植物根系分泌物对线虫发育和对植物侵染的生物学机制,提出根际调控措施。在J2时期利用抗性/非寄主植物根系分泌物,调控根结线虫Mi-16D10、Mi-flp-18等基因和孢囊线虫的Hg-rbp-2等基因的表达控制线虫的发育、侵染和迁移,通过生物源功能物质定向防控线虫侵染作物。这些结果加深了我们对生物活性物质调控植物寄生线虫机制的认识。未来,以筛选和鉴定抗性或非寄主作物特异根系分泌物对线虫侵染的调控为依据,配置生物功能型肥料,利用植物源活性物质替代传统农药控制线虫病害的根际调控措施,定向调控植物根际生物学过程将成为国内外研究热点。此文将为未来深入系统地研究根系分泌物–线虫的相互作用及克服连作障碍提供理论基础,进而促进土壤健康和作物优质高产高效,对实现绿色农业和可持续发展具有重要的理论和实践指导意义。     

营养胁迫与根系分泌物

根系不仅是活跃的吸收、代谢器官，而且是强大的分泌器官，营养元素是影响根系分泌的外界因素之一，在营养胁迫条件下，根系分泌物的组成、数量均发生变化。本文介绍了铝毒害及磷，铁。锌缺乏时，根系分泌物研究新进展。     

小麦苗期根系分泌物对根际反硝化细菌的影响

本文通过无菌水培试验，研究了两种不同基因型小麦菌期根系分泌物对反硝化细菌优势种生长量和反硝化活性的影响。结果表明：两种不同基因型的小麦根系对反硝化细菌均有明显的根际效应，其菌数和反硝化活性又以郑引１号大于宝丰７２２８；根分泌物中氨基酸组分两者相似，但其总量也以郑引１号大于宝丰７２２８，对根际反硝化细菌产生直接影响。而反硝化活性不受菌株耐药标记的影响。     

根系分泌物与养分有效性

在植物生长过程中,根系除了溢泌质子和其他无机离子外还不断地向土壤介质释放有机化合物。大体上,这些有机物质约占植株碳同化量的15-25%,高的达到40%。     

连作根系分泌物加剧土传病害的机制和缓解措施研究进展

基于植物-土壤反馈理论,连作体系中的根系分泌物必然在加剧土传病害发生中起重要作用,但相关研究证据尚缺少系统总结。本文梳理了连作导致土传病害加剧的现象以及连作对典型根系分泌物组分的累积。从有利于土传病原菌由土体向根际迁移、增殖和致病（“利病”）、破坏根际有益微生物群落防线（“压益”）和毒害根系免疫系统（“自毒”）等三个方面,揭示连作根系分泌物中某些物质促进土传病原菌入侵的机制。从根系分泌物角度阐述轮作、间作、套作、伴生和嫁接等多样性种植方式缓解连作土传病害的机制。提出鉴定“利病”、“压益”和“自毒”物质以及构建对应的消减技术途径,可为土传病害绿色高效综合防控提供理论和技术支撑。     

我国南方红壤酸化问题及改良修复技术研究进展

  目的  研究间作对作物根际土壤理化性质、球囊霉素相关土壤蛋白含量和AMF群落的影响,为我国南方红壤坡耕地种植模式的选择提供理论依据。  方法  以红壤坡耕地为研究对象,设置玉米单作、马铃薯单作、玉米与马铃薯间作3个处理,分析各作物在不同种植模式下其根际土壤理化性质、球囊霉素相关土壤蛋白含量、AMF群落的组成和多样性的变化,以及各指标之间的相互关系。  结果  玉米、马铃薯间作与单作相比均显著增加了两种作物根际土壤总球囊霉素和易提取球囊霉素含量,增加幅度为10.5% ~ 30.1%。玉米间作与玉米单作相比根际土壤有机质含量显著降低了10.6%,马铃薯间作与马铃薯单作相比根际土壤有机质和速效磷含量分别显著增加了13.5%和46.5%。玉米间作相比于玉米单作其根际土壤AMF群落特有的操作分类单元数量有增加趋势,而马铃薯间作相比马铃薯单作有降低趋势。非度量多维尺度法分析结果表明,种植模式较明显的改变了玉米根际土壤中AMF的群落组成,但没有明显改变马铃薯根际土壤中AMF的群落组成。玉米间作与玉米单作相比根际土壤AMF群落的Chao1指数显著增加了9.3%,香农指数有增加趋势,其值为1.3%,辛普森指数有降低趋势,其值为7.6%。马铃薯间作与马铃薯单作相比根际土壤AMF群落的辛普森指数有增加趋势,其值为53.3%,Chao1指数显著降低了10.8%,香农指数有降低趋势,其值为10.6%。在玉米、马铃薯的各处理中,根际土壤AMF群落优势属为巨孢囊霉属、无梗囊霉属和根孢霉属。冗余分析得出,pH是影响作物根际土壤AMF群落丰度、α多样性指数和球囊霉素相关土壤蛋白含量的主要因素。  结论  玉米与马铃薯间作可显著增加作物根际土壤的球囊霉素相关土壤蛋白含量,提高玉米根际土壤AMF群落组成的多样性,这一研究结果可为云南省红壤坡耕地种植模式的选择提供理论依据。     

Plant species richness leaves a legacy of enhanced root litter-induced decomposition in soil

Increasing plant species richness generally enhances plant biomass production, which may enhance accumulation of carbon (C) in soil. However, the net change in soil C also depends on the effect of plant diversity on C loss through decomposition of organic matter. Plant diversity can affect organic matter decomposition via changes in litter species diversity and composition, and via alteration of abiotic and/or biotic attributes of the soil (soil legacy effect). Previous studies examined the two effects on decomposition rates separately, and do therefore not elucidate the relative importance of the two effects, and their potential interaction. Here we separated the effects of litter mixing and litter identity from the soil legacy effect by conducting a factorial laboratory experiment where two fresh single root litters and their mixture were mixed with soils previously cultivated with single plant species or mixtures of two or four species. We found no evidence for litter-mixing effects. In contrast, root litter-induced CO₂ production was greater in soils from high diversity plots than in soils from monocultures, regardless of the type of root litter added. Soil microbial PLFA biomass and composition at the onset of the experiment was unaffected by plant species richness, whereas soil potential nitrogen (N) mineralization rate increased with plant species richness. Our results indicate that the soil legacy effect may be explained by changes in soil N availability. There was no effect of plant species richness on decomposition of a recalcitrant substrate (compost). This suggests that the soil legacy effect predominantly acted on the decomposition of labile organic matter. We thus demonstrated that plant species richness enhances root litter-induced soil respiration via a soil legacy effect but not via a litter-mixing effect. This implies that the positive impacts of species richness on soil C sequestration may be weakened by accelerated organic matter decomposition.     

Plant root morphology and soil biological indicators under primary development of various swards

Plant nutrition conditions are limited in naturally acidic soil due to harmful hydrogen and aluminium ions. More favourable conditions for plant nutrition (soil liming) will affect root qualitative and quantitative parameters and influence ecosystem stability. Four legume–grass swards were cultivated. The swards were a combination of one species of legume and two species of grasses: Trifolium pratense L., Trifolium repens L., Trifolium hybridum L., Medicago sativa L. (each of 50%) with Phleum pratense L. (35%) and Poa pratensis L. (15%). The aim of this study is to evaluate the root morphological and soil biological indicators of legume–grass swards under the first two years of development in soils with different pH levels.

Sward ecosystem development depends on the pH of the soil, sward species composition and soil biota. During the first year of sward development, soil pH had a significant influence on the morphology of root system. Sward‘s root mass and total root length was 2.4 and 2.2 times bigger in naturally acidic soil. This resulted in a change of biological parameters.

In the second year of sward development, soil pH had no significant influence on sward‘s root mass. However, under the impact of different soil pH, various sward‘s root systems were formed and the root C:N ratio had changed. It is observed that, regardless of the sward species composition and the year of development, at higher root C:N ratio soil microbial biomass was higher and CO₂ emissions were lower in swards in naturally acidic soils.

Regardless of soil pH, different types of clover–grass swards promoted organic carbon immobilization in microbial biomass and, at the same time, stabilized the sward ecosystem in the top soil layer (soil respiration in 0–10 and 10–20?cm layers was lower) more effectively than the alfalfa–grass sward.     

Plant mineral contents of root tips from four sorghum cultivars after exposure to the anion channel blocker,sits

SITS (0, 0.01, 0.1, or 1.0 mM) influence on the absorption (1 hr) by 1‐cm root tips of Sorghum bicolor (L.) Moench cv GP‐10, SC 283, SC 574, or Funk G522DR seedlings of calcium (Ca), boron (B), phosphorus (P), zinc (Zn), manganese (Mn), iron (Fe), magnesium (Mg), and copper (Cu) from an Hoagland and Arnon complete mineral nutrient solution was evaluated by inductively coupled plasma emission spectrophotometry (ICP). Cultivar variation in response to SITS within each element was found. Multiple mechanisms of control for the absorption of each element among cultivars were evident.     

黄土退耕坡地植物根系分布特征及其对土壤养分的影响

为明确黄土退耕坡地植物根系分布特征及其对土壤养分的影响,在陕西神木六道沟流域选取退耕30 a的长芒草坡地和裸地坡面,利用图像处理和常规分析方法研究了长芒草根系和土壤养分在土壤剖面分布及其相互关系。结果表明：长芒草根系主要分布在0～50 cm土层,分布规律可用指数函数来模拟。有根系存在的土壤表层有机质、全氮、全磷、硝态氮和铵态氮含量均高于无根系存在的坡面。在有根系存在时土壤有机质、全氮和硝态氮的具有明显的表聚现象。0～ 50 cm有机质、全氮、硝态氮和铵态氮随深度的变化可用幂函数来表示,而全磷随深度呈线性相关。0～50 cm的土壤养分与根长密度的关系可以用线性函数来表示。其研究结果为坡面退耕地土壤管理提供科学依据。     

Phosphorus affects storage root yield of cassava through root numbers

Abstract

The objective of this study was to determine the effect of phosphorus applied through fertigation on growth and root yield of cassava. This was achieved through a greenhouse pot-experiment consisting of 1, 4, 7, 10, 20 and 30?mg?P?L^?1. Increasing P from 1 to 30?mg?P?L^?1 realized a 57.1 and 150.0% increase in leaf blade P in 2014 and 2015, respectively. Similarly, chlorophyll content and shoot growth increased as P concentration in solution increased. However, leaf stomatal conductance and net photosynthesis reached a maximum in 7 and 20?mg?P?L^?1 in 2014 and 2015, respectively. This trend of stomatal conductance and net photosynthesis was consistent with that of dry root yield and storage roots numbers. Regressing dry root yield against storage root numbers showed that R² = 0.80. Phosphorus encourages formation of storage roots and the duration of cassava’s growth affects the amount of P required for maximum root yield.     

On the absorption of water and salt by the rice Plant root system,Especially mutual relationship between young and old roots

GILE et al (2) grew rice or corn with one half of the roots in a solution lacking in one element and the other half in a complete solution, and found out that these plants could absorb approximately three-fourths as much ion as the normal plants. Therefore, when a portion of the root is supplied with an ion, ion absorption by the roots may be greater than normal plants. For example, in their experiments, nitrogen absorbed per gram of roots, by the partial-nitrogen p!ants amounted to 1.45 times as much as the normal plants.     

生物菌肥对青钱柳根构型和根系形态的影响

青钱柳是我国重要的药用植物之一,研究生物菌肥对其生长、根系构型和根系性状的影响,可为立地困难的青钱柳人工林的高效栽培提供依据.试验用生物菌肥包括2种解鳞菌即巨大芽孢杆菌M(Bacillus megaterium)和荧光假单胞菌F(Pseudomonas fluorescens)、2种固氮菌即褐球固氮菌C(Azotoba...