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1.
利用根系分隔试验的方法,研究了桑树/大豆间作体系中植株生长、根际土壤酶和土壤微生物的变化.结果表明:根系不分隔处理的桑树和大豆的株高、叶片数、根长和根冠比等生长指标均高于塑料膜分隔和尼龙网分隔处理,大豆有效根瘤数较多.不分隔、尼龙网分隔处理的桑树和大豆的根际土壤磷含量比塑料膜分隔分别高10.3%、11.1%和5.1%、4.6%.不分隔和尼龙网分隔处理的桑树和大豆根际微生物数量、微生物多样性和土壤酶活性均高于塑料膜分隔处理.表明桑树和大豆间作具有明显的种间促进效应.  相似文献   

2.
为了探究种间竞争对香蒲(Typha domingensis)与芦苇(Phragmites australis)生长的影响,利用根系分隔盆栽试验研究了3种不同分隔方式条件下香蒲与芦苇的种间竞争特性,包括塑料膜分隔(根系完全分隔,无相互作用,无物质交换)、尼龙网分隔(根系部分分隔,无相互作用,有物质交换)和不分隔(根系完全相互作用,有物质交换),分析了香蒲与芦苇根系形态和地上部生长的变化,探究香蒲与芦苇种间竞争的差异。结果发现(1)在尼龙网分隔和不分隔处理中芦苇具有明显的劣势。与塑料膜分隔处理相比,芦苇的总生物量、植株密度在尼龙网分隔和不分隔处理中分别减少了39.14%、49.41%和82.08%、79.22%,总根长、总根表面积、总根体积分别减少了40.53%、44.84%、62.52%和85.7%、82.45%、89.67%,且均具有极显著差异(P<0.01);根系分隔方式也影响芦苇的株高、茎粗和叶片数,表现为不分隔 > 塑料膜分隔 > 尼龙网分隔。(2)与塑料膜分隔处理相比,香蒲总生物量在尼龙网分隔和不分隔中虽有增加,但差异不显著,植株密度和株高在尼龙网分隔和不分隔处理中都有增加且具有显著差异(P<0.05),其总根长、总根表面积、总根体积在尼龙网分隔中分别增加了57.93%、26.5%、8.04%,但在不分隔处理中分别减少了11.57%、14.92%、11.39%(P<0.05),虽然根系的相互作用对香蒲根系的生长具有促进作用,但植物种间根系相互作用越强,对两者的生长越不利。(3)在不同的分隔方式中,芦苇与香蒲间也存在明显变化。在不分隔处理中,香蒲的生物量和植株密度是芦苇的1.7倍和6.74倍,与塑料膜分隔处理相比增加了6倍,表明芦苇与香蒲根系的完全相互作用,显著削减了芦苇的繁殖生长,增加了香蒲的根系分蘖。(4)通过种间相互作用强度(RII值)分析也表明,尼龙网分隔和不分隔处理下芦苇表现为抑制作用(RII值为负值),香蒲表现为促进作用(RII值为正值)。香蒲与芦苇互作对芦苇具有抑制作用,说明种间相互作用是能改变植物的适应性和植物群落的繁殖,同时也表明植物根系不仅在吸收土壤中的水和养分中起着关键作用,在种间关系中也起着重要作用。因此利用种间竞争控制植物生长,可以为保护生物多样性和生态系统的功能提供有效的技术支撑。  相似文献   

3.
小麦/大豆间作中作物种间的竞争作用和促进作用   总被引:34,自引:3,他引:31  
春小麦/春大豆间作是西北一熟制灌区广泛采用的高产种植形式.本文采用田间小区和微区根系分隔试验研究了这种种植形式作物种间的竞争作用和促进作用.结果表明,小麦/大豆间作具有明显的间作优势.土地当量比为1.23~1.26.小麦为优势种,竞争力强于大豆,具有明显的间作边行优势.小麦边行优势的1/3贡献来自于地下部.小麦收获后,大豆生长具有恢复作用,认为这种恢复作用是间作优势的机制之一.间作相对于单作两种作物的收获指数均有显著提高.收获指数的种间促进作用是间作优势的另一机制.  相似文献   

4.
为了探究氮沉降背景下杉木和浙江楠混栽苗木的生长特征, 于2019年5月模拟两种氮水平(对照 0 kg·hm-2·yr-1·N、施氮45 kg·hm-2·yr-1·N)和三种混栽方式(每盆种植1颗杉木苗木、1颗浙江楠苗木, 地上竞争被隔板完全隔绝, 地下竞争由三种根系分隔方式控制竞争强度: 塑料膜分隔-根系无竞争、尼龙网分隔-根系干扰性竞争、无分隔-根系完全竞争), 2019年生长季(5月~12月)施氮处理并对杉木和浙江楠苗木生物量、根系形态和植株元素含量进行分析。结果表明: 根系竞争对杉木和浙江楠苗木的根、冠生物量无显著影响(p>0.05)影响, 但两种苗木的根系生长随着竞争的加剧而受到抑制作用, 种间竞争特别是干扰性竞争能够促进植物对磷的吸收; 施氮后, 根系竞争促进了根、冠生物量的增加, 并对冠生物量的增加更有利, 同时, 根系干扰性竞争的促进作用最明显。另外, 两种苗木的根系生长随着竞争的加剧而受到促进作用。施氮和种间竞争均能促进植物对营养元素的吸收。  相似文献   

5.
苗锐  张福锁  李隆 《植物学报》2009,44(2):197-201
本实验选取3种对土壤氮素竞争能力不同的禾本科作物大麦(Hordeum vulgare)、小麦(Triticum aestivum)和玉米(Zea mays)分别与蚕豆(Vicia faba)间作, 建立对土壤氮素竞争能力不同的作物组合; 并采用3种分隔方式(塑料膜分隔、尼龙网分隔和无分隔)建立同一作物组合条件下作物种间根系相互作用的不同强度, 来研究不同作物组合及种间根系相互作用强度对蚕豆结瘤的影响。结果如下: (1)蚕豆的结瘤并未随3种禾本科作物氮素竞争能力的增强而增加, 但是3种间作体系蚕豆的结瘤却均表现出无分隔处理多于塑料膜分隔处理, 即同一间作体系种间根系相互作用越强, 越有利于蚕豆结瘤的产生, 存在种间互利作用; (2)在玉米/蚕豆间作体系中, 无分隔处理的蚕豆根瘤数目和根瘤重显著高于塑料膜分隔处理, 分别高出67.5%和70.1%; 在大麦/蚕豆间作体系中也表现出无分隔处理的根瘤重显著高于塑料膜分隔处理(高出46.3%); (3)玉米/蚕豆间作体系与小麦/蚕豆和大麦/蚕豆间作体系相比, 无分隔处理时土壤氮素含量显著高于后2个间作体系, 但是玉米/蚕豆间作体系对蚕豆结瘤的促进作用更强。上述结果表明, 在蚕豆/玉米间作体系中, 玉米促进蚕豆生物固氮除了氮素竞争机制外, 还可能存在其它机制。  相似文献   

6.
苗锐  张福锁  李隆 《植物学通报》2009,44(2):197-201
本实验选取3种对土壤氮素竞争能力不同的禾本科作物大麦(Hordeum vulgare)、小麦(Triticum aestivum)和玉米(Zea mays)分别与蚕豆(Vicia faba)间作,建立对土壤氮素竞争能力不同的作物组合;并采用3种分隔方式(塑料膜分隔、尼龙网分隔和无分隔)建立同一作物组合条件下作物种间根系相互作用的不同强度,来研究不同作物组合及种间根系相互作用强度对蚕豆结瘤的影响。结果如下:(1)蚕豆的结瘤并未随3种禾本科作物氮素竞争能力的增强而增加,但是3种间作体系蚕豆的结瘤却均表现出无分隔处理多于塑料膜分隔处理,即同一间作体系种间根系相互作用越强,越有利于蚕豆结瘤的产生,存在种间互利作用;(2)在玉米/蚕豆间作体系中,无分隔处理的蚕豆根瘤数目和根瘤重显著高于塑料膜分隔处理,分别高出67.5%和70.1%;在大麦/蚕豆间作体系中也表现出无分隔处理的根瘤重显著高于塑料膜分隔处理(高出46.3%);(3)玉米/蚕豆间作体系与小麦/蚕豆和大麦/蚕豆间作体系相比,无分隔处理时土壤氮素含量显著高于后2个间作体系,但是玉米/蚕豆间作体系对蚕豆结瘤的促进作用更强。上述结果表明,在蚕豆/玉米间作体系中,玉米促进蚕豆生物固氮除了氮素竞争机制外,还可能存在其它机制。  相似文献   

7.
燕麦/小麦间作对小麦生长和锰营养的影响   总被引:2,自引:0,他引:2  
通过根系分隔的盆栽试验,研究了燕麦,小麦间作对小麦生长及其锰营养的影响。结果表明:根系不分隔处理,小麦地上部干重和植株吸锰量都高于其他两种分隔方式;而根系完全分隔处理,小麦地上部植株锰含量高于其他两种分隔方式;根系不同分隔方式对川麦28土壤DTPA-Mn含量几乎没有影响,小麦9023土壤DTPA-Mn含量则以完全分隔处理高于另外两种分隔方式。推测在该间作体系中,燕麦可能通过根系分泌物来活化土壤难溶性的锰氧化物,从而促进了小麦的生长,改善了小麦的锰营养,但因其竞争能力不如小麦而消弱了自身的生长。具体原因有待于进一步试验验证。试验还发现,种植燕麦后土壤的DTPA-Mn含量要高于种植小麦后的土壤,而且燕麦地上部植株锰含量也比小麦高,表明燕麦活化、吸收土壤锰的能力强于小麦。不同间作组合时,小麦各项研究指标无一致的规律性,说明在促进小麦生长、改善小麦锰营养的能力方面,本试验采用的3个燕麦品种之间无明显差异。  相似文献   

8.
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。  相似文献   

9.
小麦和大豆叶片的报孔不均匀关闭现象   总被引:4,自引:1,他引:3  
用^14CO2放射自显影方法的研究了是小玫和大豆叶天水分胁迫下的气孔关闭状况。正常浇水的小麦和大豆叶呈现了对^14CO2的均匀吸收。在上麦与大豆叶片不对-1.75和-1.32MPa的土壤干旱条件下,两种作物叶片翥敢孔不均匀关闭。离休吾片在空气中乐易引起气孔不均匀关闭。正常供水小麦叶片在晴天中竿明显的光合竿休时,无CO2的不均匀吸收。某些明天中竿,在大豆光合行休低谷时段以较明显的气孔不均匀关闭。用气  相似文献   

10.
缺磷胁迫下的小麦根系形态特征研究   总被引:52,自引:10,他引:42  
研究了缺磷条件下不同基因型小麦(Triticum aestivum L.)苗期根系形态学适应特征,以明确环境因子对根系不同组分(根轴和侧根)生长发育调控作用的强度和根系形态与磷营养效率关系。在缺P环境中,小麦根轴数量和侧根长度明显减小,同化物向根部的分配比例增加,根轴长度、侧根数量和根系长度等均有显著提高。供试基因型小麦的根轴数量及其长度的差异在每个供磷水平及不同供磷水平之间均呈显著,说明这两种性状的差异是由基因型和环境因素共同决定的;而侧根特征的差异只在不同供磷水平间显著,表明侧根性状主要受环境因素的控制。对6种基因型小麦的研究表明,根轴数量、根轴长度、根生长角度和根系长度根角之间存在着显著的基因型差异。相关分析表明,小麦的相对产量与缺磷条件下的小麦苗期根系形态指标的交互作用之间具有显著的线性关系。这种关系说明根系形态性状可作为早期有效地筛选磷高效小麦品种的指标。  相似文献   

11.
Previous studies have shown that uniconazole inhibits ethylene synthesis and protects plants from various stresses. The present research was conducted to delineate the mechanism of ethylene inhibition by uniconazole [(E)-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol]. Following heat stress of 48°C for 3 h, the shoots of the control wheat seedlings became desiccated, and the seedlings lost 23% of their fresh mass 8 h after stress. The control soybean seedlings had epinastic unifoliate leaves 5 h after foliar application (4.4 g.a.i./ha) of the herbicide triclopyr [(3,5,6-trichloro-2-pyridinyl)oxyacetic acid]. Soil drench applications of uniconazole, a potent member of the triazole family, reduced these symptoms associated with heat and herbicide stress in wheat (5.0 mg/L) and soybean (0.4 mg/L) seedlings, respectively. Basal ethylene production was inhibited 32 and 48% by uniconazole in the wheat and acotyledonous soybean seedlings, respectively. Following a 48°C heat stress, 1-aminocyclopropane-1-carboxylic acid (ACC) levels increased 40% in both the control and uniconazole-treated wheat seedlings. After triclopyr application, ACC levels increased 400% in both the control and uniconazoletreated soybean seedlings. The increased ACC levels, following stress, were accompanied by increased ethylene production from the control, but not from the uniconazole-treated wheat and acotyledonous soybean seedlings. Uniconazole treatment did not significantly change the basal or stress-induced N-malonyl-1-aminocyclopropane-1-carboxylic acid (MACC) levels compared to controls. These results suggest that uniconazole inhibits ethylene synthesis by interfering with the conversion of ACC to ethylene in wheat and acotyledonous soybean seedlings. Ethylene production and ACC conversion were not inhibited by uniconazole in excised soybean cotyledons. These results indicate that different ethylene-forming enzyme (EFE) systems operate in the soybean acotyledonous seedling and cotyledon, and the system in the former is inhibited by uniconazole.  相似文献   

12.
Uniconazole inhibits stress-induced ethylene in wheat and soybean seedlings   总被引:2,自引:0,他引:2  
Previous studies have shown that uniconazole inhibits ethylene synthesis and protects plants from various stresses. The present research was conducted to delineate the mechanism of ethylene inhibition by uniconazole [(E)-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol]. Following heat stress of 48°C for 3 h, the shoots of the control wheat seedlings became desiccated, and the seedlings lost 23% of their fresh mass 8 h after stress. The control soybean seedlings had epinastic unifoliate leaves 5 h after foliar application (4.4 g.a.i./ha) of the herbicide triclopyr [(3,5,6-trichloro-2-pyridinyl)oxyacetic acid]. Soil drench applications of uniconazole, a potent member of the triazole family, reduced these symptoms associated with heat and herbicide stress in wheat (5.0 mg/L) and soybean (0.4 mg/L) seedlings, respectively.Basal ethylene production was inhibited 32 and 48% by uniconazole in the wheat and acotyledonous soybean seedlings, respectively. Following a 48°C heat stress, 1-aminocyclopropane-1-carboxylic acid (ACC) levels increased 40% in both the control and uniconazole-treated wheat seedlings. After triclopyr application, ACC levels increased 400% in both the control and uniconazoletreated soybean seedlings. The increased ACC levels, following stress, were accompanied by increased ethylene production from the control, but not from the uniconazole-treated wheat and acotyledonous soybean seedlings. Uniconazole treatment did not significantly change the basal or stress-induced N-malonyl-1-aminocyclopropane-1-carboxylic acid (MACC) levels compared to controls. These results suggest that uniconazole inhibits ethylene synthesis by interfering with the conversion of ACC to ethylene in wheat and acotyledonous soybean seedlings. Ethylene production and ACC conversion were not inhibited by uniconazole in excised soybean cotyledons. These results indicate that different ethylene-forming enzyme (EFE) systems operate in the soybean acotyledonous seedling and cotyledon, and the system in the former is inhibited by uniconazole.  相似文献   

13.
Chloroplasts were isolated from primary leaves of wheat 12 days after germination and incubated at 25° for 45 min in the dark with soybean lipoxygenase-1. The lipoxygenase action was evident from a weak oxygen uptake of ca 0.18, μmol/hr per mg chloroplast protein. The lipoxygenase treatment caused a marked decrease in the photochemical activity, as measured by the reduction rate of 2,6-dichlorophenolindophenol. However, both the content and composition of the lipids as well as those of total fatty acids remained largely unchanged except for a slight but significant decrease in the total linolenic acid content. It is proposed that soybean lipoxygenase-1 selectively attacks free linolenic acid present in chloroplasts, followed by a chlorophyll-catalysed reaction of hydroperoxylinolenic acid with components of the electron transfer system.  相似文献   

14.
The results of the numerous measurements obtained during the last 40 years on gas exchange rate, photosynthetic carbon metabolism by exposition in 14CO2 and activities of primary carbon fixation enzyme, ribulose‐1,5‐bisphosphate carboxylase/oxygenase (RuBPC/O), in various wheat and soybean genotypes grown over a wide area in the field and contrasting in photosynthetic traits and productivity are presented in this article. It was established that high productive wheat genotypes (7–9 t ha?1) with the optimal architectonics possess higher rate of CO2 assimilation during the leaf ontogenesis. Along with the high rate of photosynthesis, high values of photorespiration are characteristic for the high productive genotypes. Genotypes with moderate (4–5 t ha?1) and low (3 t ha?1) grain yield are characterized by relatively low rates of both CO2 assimilation and photorespiration. A value of photorespiration constitutes 28–35% of photosynthetic rate in contrasting genotypes. The activities of RuBPC and RuBPO were changing in a similar way in the course of the flag leaf and ear elements development. High productive genotypes are also characterized by a higher rate of biosynthesis and total value of glycine–serine and a higher photosynthetic rate. Therefore, contrary to conception arisen during many years on the wastefulness of photorespiration, taking into account the versatile investigations on different aspects of photorespiration, it was proved that photorespiration is one of the evolutionarily developed vital metabolic processes in plants and the attempts to reduce this process with the purpose of increasing the crop productivity are inconsistent.  相似文献   

15.
RNA synthesis in germinating embryonic axes of soybean and wheat   总被引:2,自引:2,他引:0       下载免费PDF全文
The rate of synthesis of RNA during early germination of wheat and soybean embryos was investigated by ascertaining the incorporation of radioactive uridine into RNA. In wheat embryos, where the lag period preceding rapid growth is 5.5 hours, there is a 2-fold increase in RNA synthesis between 1.5 and 5.5 hours, with half of the increase occurring by 3.5 hours. In soybean axes, where the lag period is 9.5 hours, the increased rate of RNA synthesis is 5.5-fold between 1.5 and 9.5 hours, with three fourths of this increase occurring after 4 hours.  相似文献   

16.
The characteristics of ethylene production and ACC conversion in 8-day-old soybean seedlings were examined and a relationship between cytochrome P-450 activity and ethylene-forming enzyme (EFE) activity was found. An atmosphere containing 10% carbon monoxide (CO) significantly inhibited ethylene production and ACC conversion in control soybean seedlings, but had only a slight effect on soybean seedlings treated with uniconazole. Foliar application of triclopyr, a pyridine analogue of the phenoxy herbicides, significantly increased ethylene production and ACC conversion in control, but not in uniconazoletreated seedlings. Triclopyr treatment also resulted in a three-fold increase in extractable cytochrome P-450 of 5-day-old etiolated soybeans. At equimolar concentrations tetcyclacis was more effective than uniconazole in reducing shoot elongation and endogenous ethylene production. Although uniconazole and tetcyclacis did not inhibit ACC conversion in nonherbicide-treated soybean seedlings, they did prevent the observed increase in ACC-dependent EFE activity following triclopyr application. However, the rate of ACC conversion in etiolated soybean segments was sensitive to uniconazole, and tetcyclacis inhibited the rate of ACC conversion by 2.6-fold in etiolated soybean segments within 4 h after treatment. Microsomal membranes were isolated from 5-day-old naphthalic anhydride-treated etiolated wheat shoots as this tissue contains much higher cytochrome P-450 levels than soybean shoots. Optical difference spectroscopy demonstrated that ACC generated binding spectrum characteristic of a reverse-type-I cytochrome P-450 substrate when combined with reduced microsomes. In vitro conversion of ACC to ethylene by microsomal membranes was NADPH-dependent, inhibited by CO, and had an apparent Km and Vmax of 45 M and 0.345 nl/mg protein/h, respectively. These results suggest that cytochrome P-450-mediated monooxygenase reactions may be intimately involved in the conversion of ACC to ethylene in young soybean and wheat seedlings.  相似文献   

17.
Changes in bread-baking properties of wheat flour caused by soybean lipoxygenase and polyunsaturated fatty acids were studied. A positive effect of soybean flour added during dough kneading in an amount of 2% was demonstrated. A method for dough fermentation increasing the loaf volume and improving organoleptic characteristics and total bread-baking estimate is recommended.  相似文献   

18.
Changes in bread-baking properties of wheat flour caused by soybean lipoxygenase and polyunsaturated fatty acids were studied. A positive effect of soybean flour added during dough kneading in an amount of 2% was demonstrated. A method for dough fermentation increasing the loaf volume and improving organoleptic characteristics and total bread-baking estimate is recommended.  相似文献   

19.
Goos  R. J.  Johnson  B. E.  Carr  P. M. 《Plant and Soil》2001,235(2):127-133
On fields with no history of soybean (Glycine max (L.) Merr.) production, inoculation alone is often inadequate to provide for adequate nodulation the first time this crop is grown. The objective of this study was to determine if inoculation of spring wheat (Triticum aestivum L.) seed with Bradyrhizobium japonicum would lead to an increase of B. japonicum numbers in the soil, and improve nodulation of a subsequent soybean crop. In the greenhouse, wheat seed inoculation increased B. japonicum numbers from undetectable numbers to >9000 g–1 of soil, whereas the numbers of introduced B. japonicum declined in unseeded pots. In the field, inoculation of wheat seed increased B. japonicum numbers in the soil from undetectable levels to >4000 g–1 the following year. When soybean seed was inoculated, but grown in soil devoid of B. japonicum, nodules formed only near the point of seed placement. The heaviest nodulation, and widest distribution of nodules in the topsoil were found whenB. japonicum was established the year before by wheat seed inoculation, plus soybean seed inoculation. Wheat seed inoculation the year before growing soybean, combined with proper soybean seed inoculation, should provide for abundant nodulation the first time soybean is grown on a field.  相似文献   

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