不同磷水平下小麦-蚕豆间作根系形态的变化及其与内源激素的关系

采用水培方法,研究了不同磷水平下小麦-蚕豆间作体系根系形态变化及其与内源激素的相关关系。结果表明: 与单作小麦相比,在低磷(1/2P)水平下,小麦-蚕豆间作能显著增加小麦的根长,显著减少小麦根系的平均直径,显著增加根系的表面积;在常规磷(P)水平下,间作能显著降低小麦根系的平均直径,有增加小麦根长和根表面积的趋势;与单作蚕豆相比,间作能明显促进蚕豆根系的增长,同时增加蚕豆根表面积。在1/2P水平下,间作能显著提高小麦和蚕豆根系中的生长素(IAA)、脱落酸(ABA)、水杨酸(SA)和茉莉酸(JA)含量;在P水平下,间作能显著提高小麦根系中的IAA、ABA和JA含量,单、间作小麦根系中的SA含量没有显著差异,间作显著增加了蚕豆根系中ABA和SA含量,单、间作蚕豆根系中的IAA和JA含量无显著差异。单作条件下,小麦和蚕豆根系中的内源激素(IAA、ABA、SA和JA)含量与其根系形态(根长、根平均直径和根表面积)无显著相关性;间作条件下,小麦和蚕豆根系中的IAA含量与根长和根表面积之间存在明显的正相关关系。由此可见,小麦-蚕豆间作能够诱导小麦和蚕豆根系IAA的增加。这种变化可能是驱动间作系统根系形态变化的重要因子。     

不同品种小麦与蚕豆间作对蚕豆枯萎病的防治及其机理

通过田间小区试验和水培试验,研究了3个品种小麦（云麦42、云麦47和绵阳29）与蚕豆间作对蚕豆地上部生物量、枯萎病发生、根际微生物代谢功能多样性和枯萎病病原菌尖孢镰刀菌数量的影响,分析了3个不同小麦品种低分子量根系分泌物组分（糖、氨基酸和有机酸）的差异.结果表明： 云麦42与蚕豆间作（YM42/B）和云麦47与蚕豆间作（YM47/B）使蚕豆地上部生物量分别增加16.6%和13.4%,使蚕豆枯萎病病情指数分别降低47.6%和23.3%,绵阳29与蚕豆间作（MY29/B）对蚕豆地上部生物量和枯萎病病情指数均无显著影响.与单作蚕豆相比,YM42/B和YM47/B处理均显著提高了蚕豆根际微生物的平均颜色变化率（AWCD)及对碳源的总利用强度和Biolog ECO板中各种碳源的利用,明显改变了蚕豆根际微生物群落结构,并显著降低了蚕豆根际的尖孢镰刀菌数量;MY29/B处理对AWCD值、碳源总利用强度和Biolog ECO板中各种碳源的利用及蚕豆根际尖孢镰刀菌数量均无显著影响,也未明显改变蚕豆根际的微生物群落结构.3个小麦品种根系分泌物中可溶性糖、游离氨基酸总量和有机酸总量均表现为MY29＞YM47＞YM42.MY29根系分泌物中丝氨酸、谷氨酸、甘氨酸、缬氨酸、蛋氨酸、苯丙氨酸、赖氨酸的含量均显著高于YM42和YM47;精氨酸为YM42、YM47所特有,而亮氨酸为MY29所特有.MY29和YM47根系分泌物中检出酒石酸、苹果酸、柠檬酸、琥珀酸、延胡索酸和顺乌头酸6种有机酸,而YM42根系分泌物中检出洒石酸、苹果酸、柠檬酸和延胡索酸4种有机酸,且MY29和YM47根系分泌物中苹果酸含量显著高于YM42.小麦与蚕豆间作提高了蚕豆根际微生物的活性和碳源利用强度,改变了根际微生物的群落结构,降低了蚕豆根际尖孢镰刀菌的数量,促进了蚕豆生长,抑制了蚕豆枯萎病的发生,但小麦与蚕豆间作控病效果受小麦品种的影响,表明间作系统中非寄主作物根系分泌物的差异是影响间作对土传病害控制的重要因素.     

丛枝菌根真菌对三叶草根系分泌的有机酸组分和含量的影响

比较洗根法、层析纸法和琼脂膜法收集土培条件下生长的菌根化和非菌根化三叶草根分泌物的效果。试验采用三室根箱装置 ,将根系与菌丝生长空间分开 ,三叶草生长 5 6d后 ,打开三室根箱装置 ,由于尼龙网的阻挡作用使根系均匀垫积在尼龙网内侧并形成根垫。分别采用洗根法、层析纸法和琼脂膜法 3种方法收集三叶草根系分泌物 ,并通过高效液相色谱方法测定分泌物中草酸、酒石酸、苹果酸、乳酸、乙酸、顺丁烯二酸、反丁烯二酸、柠檬酸、丁二酸等有机酸的含量。结果表明 :3种收集方法收集的三叶草分泌的有机酸无论在种类上还是在数量上都存在相当大的差别。从检测到的有机酸种类来看 ,琼脂膜法收集检测到苹果酸、乙酸、顺丁烯二酸、柠檬酸、丁二酸和乳酸 6种有机酸 ;洗根法收集的分泌物检测到酒石酸、苹果酸、乙酸、顺丁烯二酸、柠檬酸、丁二酸和乳酸 7种有机酸 ;层析纸法收集的分泌物检测到酒石酸、苹果酸、柠檬酸和乳酸 4种有机酸。从收集到的有机酸数量来看 ,洗根法收集到的有机酸总量为 2 9.97～ 2 32 .7μg/( gfw· 2 h) ;琼脂膜法集到的有机酸总量为 1 .5～ 7.3μg/( cm2· 2 h) ;层析纸法收集的有机酸总量为0 .2 3～ 6.5 8μg/( cm2 · 2 h)。丛枝菌根真菌侵染对三叶草根系分泌的有机酸的组分和含量都有一     

小麦与蚕豆间作体系根系形态与磷吸收的定量解析

豆科与禾本科作物间作能够改变作物根系生长,但不同施磷水平下间作-根系形态-磷吸收之间的关系尚未明确。本研究通过田间定位试验和根箱模拟试验,研究不同种植模式(小麦单作、蚕豆单作和小麦-蚕豆间作)和不同磷水平下小麦和蚕豆的产量、生物量、磷吸收及根系形态特征,分析探讨不同施磷条件下小麦-蚕豆间作对根系形态和磷吸收的影响。结果表明: 根箱试验中,与单作相比,间作小麦的根干重、根冠比分别增加21.2%、61.5%,地上部干重降低14.6%,根系磷含量和总吸磷量分别提高23.8%和12.1%;间作蚕豆的地上部干重、根干重、根冠比、总根长和根体积分别增加16.5%、47.3%、24.0%、3.5%和8.4%,间作蚕豆地上部磷含量、根系磷含量和总吸磷量分别提高14.7%、26.2%和21.5%。田间试验中,与单作相比,分蘖期间作小麦地上部磷吸收量降低8.7%,而在拔节期、抽穗期、灌浆期和成熟期分别提高40.6%、19.7%、7.8%和12.4%;但种间互作导致开花期、结荚期和成熟期间作蚕豆的地上部磷吸收量分别降低9.8%、9.0%和5.2%。偏最小二乘法(PLS)回归分析表明,小麦的根表面积和根体积、蚕豆的根表面积对作物磷吸收的贡献最大,在低磷胁迫条件下,间作同时提高了小麦和蚕豆的根体积和根表面积,促进了磷的吸收。总之,在缺磷或低磷条件下,种间互作扩大了小麦和蚕豆根土接触面积,促进了苗期磷的吸收,为后期间作优势的形成奠定了基础。     

缺磷白羽扇豆排根与非排根区根尖分泌有机酸的比较

采用根系分泌有机酸原位收集方法及高效液相色谱技术分析了供磷及缺磷后不同时间白羽扇豆(LupinusalbusL .)非排根区根尖和排根分泌有机酸的种类和数量 ,以及相应的根尖、排根组织 ,茎木质部、韧皮部汁液中有机酸含量的变化。结果表明 :(1)缺磷能够诱导白羽扇豆根系产生大量排根 ,根系的有机酸分泌量也明显增加。 (2 )无论在供磷或缺磷条件下 ,排根与非排根区根尖组织中的有机酸种类相同 ,但排根主要分泌柠檬酸和苹果酸 ,而非排根区根尖主要分泌苹果酸和乙酸。 (3)缺磷后非排根区根尖分泌苹果酸的量增加 ,至第 17天达到高峰 ;排根开始分泌柠檬酸的时间相对较晚。缺磷后排根分泌柠檬酸的量随缺磷时间的延长不断增加。 (4 )在缺磷的排根与非排根区根尖组织和茎木质部伤流液中含有大量柠檬酸和苹果酸 ,但在茎韧皮部汁液中则几乎检测不到这两种有机酸。上述结果表明 ,尽管排根和非排根区根尖组织中的有机酸种类相同 ,但它们向外分泌的有机酸种类不同。缺磷后排根及非排根区根尖增加向外分泌的有机酸主要在根中合成     

铝胁迫下黑麦和小麦根尖分泌有机酸的研究

通过建立的活体根培养及微量根尖分泌物收集系统,对铝胁迫下黑麦和小麦根尖分泌的有机酸进行研究。结果表明:50、100、200、300μmol·L-1 AlCl3处理后黑麦根尖分泌柠檬酸和苹果酸,而铝仅诱导小麦根尖分泌苹果酸。铝处理3h后,根尖分泌的苹果酸显著增加,并在9h内维持较高的分泌速率。铝诱导黑麦根尖分泌柠檬酸有明显的迟缓期,Al(300μmol·L-1)处理后的最初3h,根尖分泌的柠檬酸并不显著增加。在铝溶液中添加的阴离子通道抑制剂A-9-C(20、60、100μmol·L-1)显著抑制根尖分泌有机酸。然而,将黑麦根尖浸泡于含异三聚体G蛋白激活剂霍乱毒素(50ng·mL-1)后,根尖分泌的有机酸显著增加。说明建立的微量根尖分泌物收集系统适合于铝诱导根尖分泌有机酸的研究,小麦和黑麦根尖在铝胁迫下以不同模式通过阴离子通道分泌有机酸,而异三聚体G蛋白可能介导根尖分泌有机酸。     

低磷胁迫下AM真菌对枳实生苗吸磷效应及根系分泌有机酸的影响

在温室沙培灭菌条件下,以Al-P为磷源、枳为试材、Glomus mosseae (G.m)和G.versiforme (G.v)为菌剂,研究低磷胁迫下AM真菌对枳实生苗干物重、吸磷效应及根系分泌有机酸的影响。结果表明,接种AM真菌显著增加枳地上部、地下部干物重,增幅16.79%~135.25%;同时显著增加其吸磷量,菌丝对植株的吸磷贡献率为17.04%~71.95%(G.m>G.v),施Al-P显著提高菌丝吸磷贡献率。接种AM真菌的根系分泌的有机酸种类与对照有所不同,未接种处理枳分泌的有机酸有草酸、苹果酸、乳酸、乙酸、顺丁烯二酸和柠檬酸等6种,而接种G.m的则检测到草酸、酒石酸、苹果酸、乳酸、乙酸、柠檬酸、丁二酸等7种,G.v处理的检测到酒石酸,接种处理均未检测到顺丁烯二酸;接种丛枝菌根真菌增加了枳根系分泌有机酸的量(比未接种处理增加19.80~56.87 mg/kg,且施用AlPO₄后有机酸含量显著增加(增加20.06~21.84 mg/kg);未接种植株根系仅分泌少量有机酸;接种植株根系分泌的有机酸以苹果酸(42.87%)、柠檬酸(39.22%)和草酸(12.06%)为主。     

缺磷白羽扇豆排根与非排根区根尖分泌有机酸的比较

采用根系分泌有机酸原位收集方法及市郊液相色谱技术分析了供磷及缺磷后不同时间白羽扇豆（Ｌｕｐｉｎｕｓ ａｉｂｕｓ Ｌ．）非排根区根尖和排根分泌有机酸的种类和数量,以及相应的根尖、排根组织,茎木质部、韧皮部汁液中有机酸含量的变化。结果表明：⑴缺磷能够诱导白羽扇豆要系产生大量排根,根系的有机酸分泌量也明显增加。⑵无论在供磷或缺磷条件下,排根与非排根区根区根尖组织中的有机酸种类相同,但排根主要分泌柠檬酸和     

小麦蚕豆间作对蚕豆根际微生物群落功能多样性的影响及其与蚕豆枯萎病发生的关系

通过田间小区试验,研究了小麦与蚕豆间作对蚕豆枯萎病发生和根际微生物代谢功能多样性的影响。结果表明,小麦与蚕豆间作使蚕豆枯萎病的发病率和病情指数分别比单作显著降低20%和30.4%。与单作处理相比,间作显著增加了蚕豆和小麦根际微生物对31种碳源的平均利用率（AWCD）,其中间作蚕豆的AWCD值最高,比单作增加82.7%,单作蚕豆最低。间作蚕豆和间作小麦根际微生物的Shannon多样性指数与丰富度指数均显著高于单作,间作使蚕豆和小麦的丰富度指数分别增加29.2%和30.3%。根际微生物对六类碳源的利用强度百分比以糖类、羧酸类和氨基酸最高,分别为41.96%,19.80%和18.13%。主成分分析表明,小麦与蚕豆间作改变了根际微生物的群落组成;相关分析表明,糖类、羧酸类和氨基酸类碳源是区分单间作处理差异的主要碳源,其中氨基酸类碳源是最敏感的碳源。小麦与蚕豆间作增加了根际微生物活性,提高了Shannon多样性指数和丰富度指数,改变了微生物群落功能多样性,是抑制蚕豆枯萎病的有效措施。该研究为阐明根际微生物功能多样性变化在间作体系病害控制中的作用与机制奠定了理论基础。     

一种根系分泌物中有机酸的前处理和高效液相色谱检测方法

改进了根系分泌有机酸的前处理和高效液相色谱检测方法.将DEAE纤维素层析法直接用于根系分泌物中有机酸的富集浓缩,并与旋转蒸发浓缩的回收率进行了比较.结果表明,DEAE纤维素柱层析有较高的回收率,可用于根系分泌物中有机酸的富集浓缩,特别适用于大批量样品的前处理.确定了反向高效液相色谱同时检测草酸、酒石酸、马来酸、苹果酸、乙酸、柠檬酸、琥珀酸等7种有机酸的条件.玉米根系分泌物样品中可检出苹果酸等5种有机酸.     

Wheat and faba bean intercropping changes phenolic acids from roots to rhizosphere

The changed phenolic acids (PAs) allelochemicals exuded by the roots induced by interspecific interactions is related to intercropping alleviates soil-borne disease. However, the presence of PAs in roots and root exudations and their rhizodeposition under intercropping are still unclear. Hydroponic and soil experiments of wheat, faba bean, and wheat intercropped with faba bean were conducted, and the major compositions and contents of PAs in roots, root exudations, and rhizospheric soil were determined. The results showed that ρ-hydroxybenzoic, vanillic, and syringic acids were the major components of PAs in roots, root exudations, and rhizospheric soil in a wheat and faba bean intercropping system. The compositions and percentages of PAs in roots of faba bean were altered when faba bean intercropped with wheat. The total exudation rate of PAs in root exudations was decreased by 30%–60% under the wheat and faba bean intercropping (W//F) system as compared to mono-cropped faba bean (MF). ρ-hydroxybenzoic acid was identified in the root exudation of both MF and mono-cropped wheat (MW), but not detected in the intercropping on 60 days after transplanting. Vanillic acid was only detected in the root exudation of MF on 30 days after transplanting. The rhizodepostion of vanillic and cumaric acid were decreased at both branching and pod setting stages in W//F as compared to MF. In conclusion, interspecific interaction changed the compositions and contents of PAs in faba bean roots and root exudations. W//F constrained vanillic acid exuded by roots and decreased vanillic and coumaric acid rhizodeposition by faba bean, which provides insight into root-soil interactions in the intercropping systems.     

Intercropping influences component and content change of flavonoids in root exudates and nodulation of Faba bean

Flavonoids produced by legume roots are signal molecules acting as nod gene inducers for the symbiotic rhizobium partner. Nevertheless, the changes of flavonoids in root exudates in intercropping system are still unknown. Based on pot experiment of faba bean and wheat intercropping, here we showed that faba bean and wheat intercropping increased the nodules number and dry weight, dry weight per nodule of faba bean compared with those found in monocropping, and the increase of faba bean nodulation was likely caused by the enhancement with flavonol, isoflavone, chalcone and hesperetin in its root exudates. It also promoted exudation of five types of flavonoids by wheat compared with monocropping. Our findings suggest that the flavonoids in root exudates have a positive effect on the nodulation and nitrogen fixation of faba bean in faba bean and wheat intercropping.     

间作减轻蚕豆枯萎病的微生物和生理机制

通过田间小区试验,研究了小麦与蚕豆间作对蚕豆枯萎病发病率、病情指数、根际镰刀菌数量、蚕豆根系抗氧化酶活性和膜质过氧化的影响.采用Biolog ECO板分析了根际土壤微生物的代谢功能多样性,通过高效液相色谱(HPLC)测定了蚕豆根际土壤中酚酸含量.结果表明: 与单作蚕豆相比,小麦与蚕豆间作有降低蚕豆枯萎病发病率的趋势;发病盛期和发病末期,间作使蚕豆枯萎病的病情指数比单作显著降低15.8%和22.8%,明显提高了蚕豆根际微生物活性(AWCD值),根际微生物的Shannon多样性指数显著提高4.4%和5.3%,丰富度指数显著提高19.4%和37.1%.主成分分析表明,发病盛期和发病末期,间作明显改变了蚕豆根际微生物的群落结构,蚕豆根际镰刀菌数量分别降低53.8%和33.1%;并显著降低了蚕豆根际土壤中对羟基苯甲酸、香草酸、丁香酸、阿魏酸、苯甲酸和肉桂酸的含量.发病盛期和发病末期,间作蚕豆根系的过氧化物酶(POD)和过氧化氢酶(CAT)活性分别显著提高了20.0%、31.3%和38.5%、66.7%,丙二醛(MDA)含量显著降低36.3%和46.3%;发病初期间作对蚕豆根系的POD、CAT酶活性和MDA含量无显著影响.小麦与蚕豆间作显著提高了蚕豆根际微生物的活性、多样性和根系抗氧化酶活性,降低了蚕豆根际土壤中酚酸含量和膜质过氧化程度,减少了土壤镰刀菌的数量,从而提高了蚕豆对枯萎病的抗性,降低了枯萎病的危害程度.     

小麦/蚕豆间作作物生长曲线的模拟及种间互作分析

物种间的相互作用与间作产量优势的形成密切相关,但很少有人注意到种间互作动态.本研究通过2年田间定位试验,运用Logistic分析模拟了不同种植模式(小麦单作、蚕豆单作和小麦/蚕豆间作)和不同磷水平下[P₀,施磷量(P₂O₅)为0 kg·hm^-2(对照);P₁,施磷量(P₂O₅)为45 kg·hm^-2;P₂,施磷量(P₂O₅)为90 kg·hm^-2]单间作小麦、蚕豆的生长模型,分析了作物种间互作的动态变化.结果表明: 小麦/蚕豆间作使小麦产量提高了10.5%~18.6%,蚕豆产量却降低了4.8%~12.3%,但间作系统仍具有产量优势,土地当量比(LER)和相对拥挤系数(K)分别为1.01~1.15 和1.12~3.20.小麦和蚕豆的产量及关键生长参数均受磷水平调控,但LER和K并不受磷水平影响.与单作相比,间作小麦的最大生长速率(R_max)和最初生长速率(r)分别提高21.8%~38.7%和20.7%~38.9%,但间作对蚕豆的关键生长参数无影响.在小麦、蚕豆的生长初期,不同磷水平下,单间作作物的生长曲线无差异;间作群体以种间竞争为主,无间作生物量优势(LER<1,K<1).当蚕豆达到最大生长速率(T_max)后,间作显著提高了小麦的生长速率,降低了小麦的种内竞争压力,表现出间作生物量和产量优势(LER>1,K>1).总之,在不同的生长发育阶段,小麦、蚕豆的相互作用不同,间作提高了中后期小麦的生长速率,为间作优势的形成奠定了基础.     

The role of maize root size in phosphorus uptake and productivity of maize/faba bean and maize/wheat intercropping systems

Interspecific root/rhizosphere interactions affect phosphorus (P) uptake and the productivity of maize/faba bean and maize/wheat intercropping systems. The aim of these experiments was to determine whether manipulation of maize root growth could improve the productivity of the two intercropping systems. Two near isogenic maize hybrids (the larger-rooted T149 and smaller-rooted T222) were intercropped with faba bean and wheat, under conditions of high- and low-P availability. The larger-rooted T149 showed greater competitive ability than the smaller-rooted T222 in both maize/faba bean and maize/wheat intercropping systems. The higher competitive ability of T149 improved the productivity of the maize/faba bean intercropping system in P-sufficient conditions. In maize/wheat intercropping systems, root growth, shoot biomass, and P uptake of maize were inhibited by wheat, regardless of the P-supply. Compared with T222, the larger-rooted T149 suffered less in the intercropping systems. The total biomass of the maize/wheat intercropping system was higher for wheat/T149 than for wheat/T222 under low-P conditions. These data suggested that genetic improvement of maize root size could enhance maize growth and its ability to compete for P resources in maize/faba bean and maize/wheat intercropping systems. In addition, depending on the P availability, larger maize roots could increase the productivity of intercropping systems.     

大豆和蚕豆苗期根系生长特征的比较

大豆和蚕豆是西北地区间套作生产中广泛种植的豆科作物,但二者在与禾本科作物间作时差异十分明显,蚕豆相对于大豆具有更强的竞争能力.从大豆和蚕豆的根系入手,研究了大豆和蚕豆在苗期根系生长发育和形态的差异.采用PVC管砂培装置,通过扫描仪扫描根系,用图像分析软件WinRHIZO进行了研究.结果表明,出苗42 d时,蚕豆根表面积是大豆根表面积的2.61倍;出苗14 d时,大豆根系在整个砂层中均有分布,而蚕豆根系只分布在表层;大豆根较细,大部分根的直径为0.2～1.0 mm,相对于大豆而言,蚕豆根较粗,大部分根直径为0.5～1.5 mm.蚕豆根较粗,所以有更大的表面积,而且它的根系分布在上层的比例大于大豆,这些因素决定了它的吸收能力强于大豆,能更好地利用上层土壤养分.这是蚕豆竞争能力强于大豆的原因之一.     

Root distribution and interactions between intercropped species

Even though ecologists and agronomists have considered the spatial root distribution of plants to be important for interspecific interactions in natural and agricultural ecosystems, few experimental studies have quantified patterns of root distribution dynamics and their impacts on interspecific interactions. A field experiment was conducted to investigate the relationship between root distribution and interspecific interactions between intercropped plants. Roots were sampled twice by auger and twice by the monolith method in wheat (Triticum aestivum L.)/maize (Zea mays L.) and faba bean (Vicia faba L.)/maize intercropping and in sole wheat, maize, and faba bean up to 100 cm depth in the soil profile. The results showed that the roots of intercropped wheat spread under maize plants, and had much greater root length density (RLD) at all soil depths than sole wheat. The roots of maize intercropped with wheat were limited laterally, but had a greater RLD than sole-cropped maize. The RLD of maize intercropped with faba bean at different soil depths was influenced by intercropping to a smaller extent compared to maize intercropped with wheat. Faba bean had a relatively shallow root distribution, and the roots of intercropped maize spread underneath them. The results support the hypotheses that the overyielding of species showing benefit in the asymmetric interspecific facilitation results from greater lateral deployment of roots and increased RLD, and that compatibility of the spatial root distribution of intercropped species contributes to symmetric interspecific facilitation in the faba bean/maize intercropping. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.