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1.
Many varieties of Italian ryegrass (Lolium multiflorum) show resistance to herbicides; while this ability was frequently attributed to alterations in the target sites of the herbicide's action of the plant or to an efficient oxidative metabolism, little attention has been paid to glutathione S-transferases (GSTs), which are a family of detoxifying enzymes involved in the inactivation of many toxic compounds. To investigate the role of GSTs, seedlings of Italian ryegrass were treated with four herbicides (atrazine, fenoxaprop-ethyl, fluorodifen, metolachlor) and a safener (fenchlorazol-ethyl). All the treatments were well tolerated by the plant, with very low decreases in terms of fresh weight and length of shoots. Regarding GST activity, the chemicals generally determined significant increases in the above enzyme activity toward the model-substrate CDNB. Therefore, the herbicides most GST inducing and the safener were tested themselves as enzyme substrates: constitutive GST activities toward atrazine, fluorodifen and fenchlorazol-ethyl were found, and, in addition, these activities were significantly induced by the safener. Following these results, a HPLC procedure was standardized in order to investigate the persistence of atrazine and fluorodifen in the seedlings of Italian ryegrass and the effect on this of the safener. It was found that the residual amounts of the two herbicides in the shoots were significantly reduced following the safener treatments.  相似文献   

2.
Thirty-nine wheat accessions were used to evaluate their extract phytotoxicity against annual ryegrass (Lolium rigidum Gaud.). Aqueous extracts of wheat shoot residues significantly inhibited the germination and root growth of a biotype of annual ryegrass resistant to herbicides of acetyl CoA carboxylase inhibitors (group A), acetolactate synthase inhibitors (B), photosystem II inhibitors (C), and tubulin formation inhibitors (D). The germination of the herbicide resistant (HR) biotype was inhibited by 3-100%, depending upon the wheat accession. The phytotoxic effects on ryegrass root growth ranged from 12% stimulation to 100% inhibition, compared to a control. The germination and root growth of a herbicide-susceptible (HS) biotype of annual ryegrass were also inhibited by the wheat extracts, with germination inhibited by 4-100%, and root growth by 19-100%. Bioassays with two known wheat allelochemicals showed that p-coumaric acid and propionic acid significantly inhibited the growth of both HR and HS biotypes of annual ryegrass. The two compounds completely inhibited the root growth of HR ryegrass at concentrations greater than 5.0 mM. In comparison with p-coumaric acid, propionic acid was more inhibitory to seed germination, shoot, and root growth of both ryegrass biotypes. The root growth of the HR biotype was more sensitive when exposed to wheat extracts, to p-coumaric acid, and to propionic acid. The results suggest that residues of certain wheat cultivars with strong allelopathic potential could provide a nonherbicidal alternative for the management of herbicide-resistant weed species.  相似文献   

3.
In order to combine the ability of legumes to fix atmospheric nitrogen and the cruciferous capacities to mobilize soil nutrients and herbicide action, the aim of this work was to evaluate an alternative winter intercrop (faba bean-rapeseed) as a replacement of Italian ryegrass culture in a rotational system with maize as summer crop. For this purpose, two adjacent plots were used during three agronomic years (2011–2012, 2012–2013 and 2013–2014) to evaluate the agronomic performance through the forage production, nutritional composition of forage and silage, and the effects on soil fertility. The Italian ryegrass was cultivated under conventional management: using chemical fertilization and recommended dosages of herbicides. The faba bean-rapeseed intercrop was cultivated under an alternative management: organic fertilization and less herbicide supply. The intercrop provides higher forage yield per hectare than Italian ryegrass, with greater protein (kg ha?1) and similar energy (GJ ha?1) yields. The intercrop allows reducing the inputs of chemical fertilization and herbicides, and it has a positive effect on the balance of soil nutrients, especially increasing the potassium, calcium and magnesium contents. The results show that faba bean-rapeseed intercrop could be an alternative to the Italian ryegrass as winter crop.  相似文献   

4.
CO2和光能是植物光合作用的动力和底物,它们的变化必然引起植物光合特性和生长的变化。研究大气CO2浓度和光强变化对植物光合生理的影响,有利于认识作物对全球生态变化的生理响应机制。试验以高大气CO2浓度和遮荫为处理手段,通过测定小麦(Triticum aestivum)旗叶的光合气体交换参数、光强光合速率响应曲线和产量构成因子,分析光强光能利用效率之间的关系,研究高大气CO2浓度(760μmol.mol 1)和遮荫对小麦叶片光合特性及产量构成因子的影响。结果表明,高大气CO2浓度下,小麦叶片的净光合速率(Pn)增加;同时最大净光合速率(Pnmax)、光饱和点(LSP)、光补偿点(LCP)显著升高;遮荫处理使小麦叶片的Pnmax、LSP、LCP降低。正常光照下大气CO2浓度升高使小麦叶片呼吸速率(Rd)显著下降,遮荫后大气CO2浓度升高对Rd无显著影响。大气CO2浓度升高能显著提高小麦叶片表观量子效率(AQY),而遮荫对AQY的影响因大气CO2浓度而异,高大气CO2浓度下遮荫使AQY显著提高,正常大气CO2浓度下遮荫则使AQY明显下降。高大气CO2浓度下遮荫使小麦株高、穗长增加,而穗粒数、单株穗粒重、千粒重减小。受光合特性的变化和光强限制,高大气CO2浓度下遮荫使小麦叶片呼吸增强,导致Pn下降,不利于干物质积累和籽粒产量的形成。  相似文献   

5.
Meyns  B.  Van de Wiele  T.  Doulami  F.  Marlé  C.  De Sloovere  A.  van de Wiele  K.  Fant  F.  Verstraete  W. 《Water, air, and soil pollution》2002,138(1-4):37-49
In this work a practical remediation technique for TNT-contaminated soils is demonstrated at the laboratory scale level. Addition of 2%% proteinaceous material and 20%% compostto a TNT-polluted soil (633 + 210 mg TNT kg-1) decreased free TNT with 87%% and water leachable TNT with 67%% after 3 weeks anaerobic incubation. Upon subsequent aerobic incubation,there was an increase in soil respiration, in the activity of both groups of nitrifiers and also in the activity of methane-oxidising bacteria compared to untreated TNT-contaminated soil.Italian ryegrass (% Lolium multiflorum var. % Bartolini)was succesfully grown after the treatment and developed an extensive root system within 28 days. After a subsequent anaerobic/aerobic phase and growth of Italian ryegrass comprisinga total treatment time of 10 weeks, earthworms were capable ofsurviving and increasing weight in the remediated soil. The overall procedure of anaerobic immobilisation and subsequent growth of Italian ryegrass offers a low-cost method for practitioners to significantly improve the quality of TNT-contaminated soils.  相似文献   

6.
施用硫肥对冬小麦光合生理特性及产量的影响   总被引：6，自引：2，他引：4  
在田间条件下,连续两年通过不同硫肥处理对多穗型小麦品种豫麦49和重穗型小麦品种豫麦66的光合特性和产量性状影响进行了系统研究。结果表明,施用硫肥对提高群体光合速率(CAP)、旗叶净光合速率(Pn)、叶绿素(Chl)含量以及硝酸还原酶(NR)活性等方面有重要作用,但不同硫肥处理之间,不同小麦品种之间存在差异。本研究结果还表明,不同的硫肥处理对提高两种穗型冬小麦产量有差异,且对产量构成因素也有不同的影响。比较硫肥不同处理对两种小麦品种光合生理特性及产量的调控作用以及投入成本来看,在目前高产田养分供应条件下,两品种均以基施S120 kg/hm2效果相对较优。  相似文献   

7.
本文研究了不同土壤水分下小麦(小偃6号)幼苗出土及幼苗生长的变化,结果表明,轻微的土壤水分亏缺使根的伸长加快,根量增加;严重的土壤水分亏缺使根和幼苗生长受抑,干旱下根/冠比增大.土壤水势低于1.80MPa时,幼苗几平不能出土.土壤水势在-0.61MPa时,形成的苗既小又弱,形成弱小苗的原因是叶片光合能力下降、呼吸增加的结果.根据实验结果本文提出,小偃6号向较旱区推广是一慎重的问题.  相似文献   

8.
The effects of lime application with multiple soil management methods and uses on dry matter (DM) yield and crude protein (CP) content of Silage maize cropping in succession with Italian ryegrass (ryegrass) from 2009 to 2014 in a southern Brazilian Oxisol were studied. The experimental design was completely randomized block in split-plot with four replications. The main plot treatments were the four soil management methods: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiseled no-tillage (CNT). The sub-plots treatments were the three uses of Italian ryegrass (ryegrass): cover crop (CC), silage (S), and grazing dairy heifers as part of integrated crop-livestock system (ICL). In all the years, the maize was sown approximately 30 days after the ryegrass desiccation with herbicide. In the medium-term (5 yrs.) after liming, soil management methods did not change DM yield and CP content in silage maize. The use of ryegrass for S and ICL did not change DM yield, but notably maintained or increased CP content in silage maize after liming. The use of ryegrass only as CC provided less measurable benefits than the combined production system of silage maize with ryegrass.  相似文献   

9.
The effects of herbicides applied to a direct drilled and traditionally tilled wheat field on trap catches of the abundant Collembola and Formicidae were examined. Significantly higher abundances of Collembola and species richness of ants were found on the direct-drilled plots. A significant effect of the herbicides, bromoxynil (C7H3Br2NO) and hoegrass (diclofop-methyl), on the activity of two of the fourteen species of surface-dwelling Collembola was detected but no effect was observed on surface-active Formicidae. Jeannenotia stachi numbers were significantly more reduced on the direct-drilled compared to the traditionally tilled plot after herbicide treatment possibly because of higher predator abundance on the latter. In the short term, herbicides have a minimal effect on most species of surface-active arthropods although Collembola were more adversely affected than Formicidae.  相似文献   

10.
随着工业和农业生产的发展,重金属、有毒有机物及其复合污染土壤日益增多,其修复问题在世界范围内是一项具有挑战性的任务。以砂质壤土为试验对象,模拟石油-铅-镉复合污染,共设置4个处理:(1)对照处理,复合污染土壤(CK);(2)不施肥处理,复合污染土壤+黑麦草(NF);(3)施氮肥处理,复合污染土壤+黑麦草+氮肥(F1);(4)施氮肥和磷肥处理,复合污染土壤+黑麦草+氮肥+磷肥(F2),研究种植黑麦草与施肥处理对石油-铅-镉复合污染土壤微生物活性的影响,以期为污染土壤修复及环境影响评价提供初步的理论基础。结果表明:黑麦草与施肥对复合污染土壤基础呼吸、微生物量碳均有促进作用,处理NF、F1和F2的土壤基础呼吸强度比对照处理CK最高分别增加约20.94%,24.41%,42.69%,其中施加氮、磷肥(F2)对土壤基础呼吸影响最显著;第10天时,处理NF、F1和F2土壤微生物量碳含量与对照相比分别增加约26.92%,127.43%,181.89%,施肥处理土壤微生物量碳含量显著高于不施肥处理;不同种类的酶活性对黑麦草与施肥的响应不尽相同,其中种植黑麦草与施肥均会抑制石油-铅-镉复合污染土壤中FDA水解酶活性,施加氮肥在一定时间内能较好地维持石油-铅-镉复合污染土壤内的脱氢酶活性,施肥能有效地提高并维持复合污染土壤中脲酶活性,而过氧化氢酶活性受黑麦草与施肥影响不显著。研究表明种植黑麦草配施氮、磷肥对土壤微生物基础呼吸、土壤微生物量碳及相关土壤酶活性均有增强作用,进而有利于促进土壤污染物的去除及土壤质量的改善。  相似文献   

11.
The chemical basis for wheat seedling allelopathy on the growth of annual ryegrass was investigated by the identification and quantification of multiple allelochemicals from wheat seedlings. Results indicated that 58 wheat accessions differed significantly in seedling allelopathy and inhibited the root growth of ryegrass from 10 to 91%, depending on accession. Analysis of allelochemicals by GC/MS/MS indicated that allelopathy was significantly correlated with the levels of measured allelochemicals in the shoots and roots of young wheat seedlings. Ryegrass root growth was also negatively correlated with the levels of p-hydroxybenzoic, vanillic, and trans-ferulic acids in root exudates. Wheat allelopathic potential was negatively correlated with the levels of the eight known allelochemicals quantified in the shoots, roots, and water-agar medium, with multiple regression coefficients (r) of -0.61, -0.71, and -0.71, respectively. In comparison with weakly allelopathic accessions, strongly allelopathic accessions produced significantly higher amounts of allelochemicals in the shoots and roots of the wheat seedlings and also exuded larger quantities of allelochemicals into the growth medium. Wheat accessions with strong seedling allelopathy might be useful for management of weeds during the establishment stage, thereby reducing the need for commercial herbicides in early-season application.  相似文献   

12.
Abstract. Leaching of nitrate from a sandy loam cropped with spring barley, winter wheat and grass was compared in a 4-year lysimeter study. Crops were grown continuously or in a sequence including sugarbeet. Lysimeters were unfertilized or supplied with equivalent amounts of inorganic nitrogen in calcium ammonium nitrate (CAN) or animal slurry according to recommended rates (1N) or 50% above recommended rates (1.5N).
Compared with unfertilized crops, leaching of nitrate increased only slightly when 1N (CAN) was added. Successive annual additions of 1.5N (CAN) or 1N and 1.5N (animal slurry) caused the cumulative loss of nitrate to increase significantly. More nitrate was leached after application of slurry because organic nitrogen in the slurry-was mineralized.
With 1N (CAN) the leaching losses of nitrate were in the following order: continuous spring barley undersown with Italian ryegrass < continuous ley of perennial ryegrass < spring barley in rotation and undersown with grass < perennial ryegrass grown in rotation = winter wheat grown in rotation < sugarbeet in rotation < continuous winter wheat < continuous barley < bare fallow.
At recommended levels of CAN (1N), cumulative nitrate losses over the four years were similar for the crops when grown in rotation or continuously. When crops received 1.5N (CAN) or animal slurry, nitrate losses from the crops grown continuously exceeded those from crops in rotation. Including a catch crop in the continuous cropping system eliminated the differences in nitrate leaching between the two cropping systems.  相似文献   

13.
Soil P transformations are primarily mediated by plant root and soil microbial activity. A short-term (40 weeks) glasshouse experiment with 15 grassland soils collected from around New Zealand was conducted to examine the impacts of ryegrass (Lolium perenne) and radiata pine (Pinus radiata) on soil microbial properties and microbiological processes involved in P dynamics. Results showed that the effect of plant species on soil microbial parameters varied greatly with soil type. Concentrations of microbial biomass C and soil respiration were significantly greater in six out of 15 soils under radiata pine compared with ryegrass, while there were no significant effects of plant species on these parameters in the remaining soils. However, microbial biomass P (MBP) was significantly lower in six soils under radiata pine, while there were no significant effects of plant species on MBP in the remaining soils. The latter indicated that P was released from the microbial biomass in response to greater P demand by radiata pine. Levels of water soluble organic C were significantly greater in most soils under radiata pine, compared with ryegrass, which suggested that greater root exudation might have occurred under radiata pine. Activities of acid and alkaline phosphatase and phosphodiesterase were generally lower in most soils under radiata pine, compared with ryegrass. The findings of this study indicate that root exudation plays an important role in increased soil microbial activities, solubility of organic P and mineralization of organic P in soils under radiata pine.  相似文献   

14.
The effects of aluminum (Al) on nitrate reductase activity, plastid pigment content, and mineral element composition in wheat, rye, and triticale seedlings were studied. Different responses of the plant species to Al content in the growth solution were observed. Under conditions of different Al concentrations (from 1 to 10 ppm), nitrate reductase (NR) activity increased in wheat and triticale, while in rye an interference with nitrate reductase by Al was observed. A definite tendency in plastid pigment content changes independent on Al levels was not found. The chlorophyll “a”;, chlorophyll “b”;, and carotenoid contents were influenced in a different way in wheat, rye, and triticale seedlings. A positive effect of 1, 5, and 10 ppm Al on the nitrogen (N) content in the shoots of wheat and rye was observed. The N content in the shoots of triticale was not affected by the presence of Al. The presence of Al in the nutrient solution led to a tendency toward reduction of potassium (K), calcium (Ca), and magnesium (Mg) contents in the shoots of rye seedlings, a reduction of K in the shoots and manganese (Mn) content in roots of wheat, and a reduction of K in both shoots and roots and an accumulation of Mn in triticale roots. In general, our investigation on the effect of Al in the early stages of wheat, rye, and triticale development showed that a large number of biochemical and physiological parameters are required to characterize the plant responses to Al stress.  相似文献   

15.
A microcosm study was conducted to investigate the effect of continuons plant defoliation on the composition and activity of microbial populations in the rhizosphere of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). Continuons defoliation of ryegrass and clover resulted in sigmficant (P <0.01) increases in soil microbial biomass, although whilst increases were measured from day 2 in soil sown with clover significant increases were only seen from day 21 in soil sown with ryegrass. These increases were paralleled, from day 10 onwards, by increases in the numbers of culturable bacteria. Numbers ofPsendomonas spp. also increased in the later stages of the study. No influence on culturable fungal populations was detected. Whilst shifts in the composition of the microbial populations were measured in response to defoliation there was little effect on microbial activity. No changes in either dehydrogenase activity or microbial respiration in the rhizosphere of ryegrass or clover were measured in response to defoliation, but both dehydrogenase activity and microbial respiration were greater in ryegrass than clover when values over the whole study were combined. Continuous defoliation resulted in significant (P <0.001) reductions in the root dry weight of ryegrass and clover, of the order 19% and 16%, respectively.  相似文献   

16.
Nitrogen (N) leaching from soil into water is a significant concern for intensively grazed forage‐based systems because it can cause a decline in water quality and is a risk to human health. Urine patches from grazing animals are the main source of this N. The objective of this study was to quantify the effect that forage type and gibberellic acid (GA) application had on N leaching and herbage N uptake from urine patches on perennial ryegrass–white clover (RGWC), Italian ryegrass and lucerne. A lysimeter study was conducted over 17 months to measure herbage growth, N uptake and N loss to water beneath each of the three forage types with the following treatments: control, urine (700 kg N/ha) and urine with GA (8 g GA active ingredient/ha). Compared with RGWC (205 kg N/ha), N leaching losses were 35.3% lower from Italian ryegrass (133 kg N/ha) and 98.5% higher from lucerne (407 kg N/ha). These differences in leaching loss are likely to be due to winter plant growth and N uptake. During the winter months, Italian ryegrass had higher N uptake, whereas lucerne had lower N uptake, compared with RGWC. The application of GA had no effect on N leaching losses, DM yield or N uptake of forage treated with 700 kg N/ha urine.  相似文献   

17.
A microcosm study was conducted to investigate the effect of continuons plant defoliation on the composition and activity of microbial populations in the rhizosphere of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). Continuons defoliation of ryegrass and clover resulted in sigmficant (P <0.01) increases in soil microbial biomass, although whilst increases were measured from day 2 in soil sown with clover significant increases were only seen from day 21 in soil sown with ryegrass. These increases were paralleled, from day 10 onwards, by increases in the numbers of culturable bacteria. Numbers ofPsendomonas spp. also increased in the later stages of the study. No influence on culturable fungal populations was detected. Whilst shifts in the composition of the microbial populations were measured in response to defoliation there was little effect on microbial activity. No changes in either dehydrogenase activity or microbial respiration in the rhizosphere of ryegrass or clover were measured in response to defoliation, but both dehydrogenase activity and microbial respiration were greater in ryegrass than clover when values over the whole study were combined. Continuous defoliation resulted in significant (P <0.001) reductions in the root dry weight of ryegrass and clover, of the order 19% and 16%, respectively.  相似文献   

18.
用磁化机对小麦干种子进行不同强度的磁化处理,大田试验发现:适宜的磁场强度可使小麦产量有较大的增加,旱地中最大增产幅度可达18.5％,同时还发现种子磁化后,其光合强度、呼吸强度以及酶的活性都增强了。用计算机对试验结果进行了曲线回归、方差分析及多重比较,得出了小麦种子磁化机的最佳磁场及其调节范围。  相似文献   

19.
以典型的磷低效(L)、吸收高效(H1)和利用高效(H2)的小麦品种及以上述品种为亲本配制的杂种F1-1(L×H1)和F1-2(L×H2)为材料,对上述品种和杂种F1的光合特性及其生理机制进行了研究。结果表明,缺磷条件下,随着叶片生长进程,供试品种和杂种F1旗叶CO2传导参数气孔导度(Gs)、叶肉导度(Gm)和碳酸酐酶(CA)活性;旗叶叶绿素含量(Chl)、光合速率(Pn)、叶绿体无机磷(PI)浓度和Mg2+-ATPase活性、可溶蛋白含量(SP)和RuBPCase活性均不断降低。不同磷效率类型品种相比,旗叶各测定时期上述参数均以L较低,H1和H2较高。与各自亲本相比,F1-1和F1-2各测定时期的光合生理参数多表现出明显的优势。表明磷高效小麦品种(H1和H2)以及杂种叶片光合碳同化特性的相对提高,是由于其光合器官捕获光能的能力较强、光合作用气孔限制和非气孔限制的程度较低和暗反应速率较高综合作用的结果。其中,磷高效品种及杂种F1叶绿体Pi供应量的增多,在维持光合器官的结构和功能中可能具有重要作用。研究还表明,供试不同磷高效小麦品种之间(吸收高效H1和利用高效H2)尽管在磷的吸收和利用特征上表现明显不同,但在叶片的光合碳同化特性及其内在生理机制上表现相似,表明控制小麦磷素吸收与利用的遗传基因位点可能与控制光合器官结构与功能的遗传位点不存在紧密连锁。在低磷胁迫条件下,充分利用杂种F1在光合碳同化特性上的杂种优势,对于改善小麦对磷素的吸收和利用以及促进子粒产量的增加具有潜在的应用价值。  相似文献   

20.
In the present study, integration of nitrogen (N) and zeolite on growth, photosynthesis, yield and yield components, nitrate reductase activity, and plant nutrient content on canola (Brassica napus L. cv. SLM046) was evaluated during two growing seasons (2010 and 2011) at East Azerbaijan Research Center for Agriculture and Natural Resources, Tabriz, Iran. The experiment was conducted as a 4?×?5 factorial design with three replications. Different levels of zeolite (0, 4, 8, and 12 ton ha?1) and nitrogen (N; 0, 150, 200, 250, and 300 kg ha?1) were added and mixed with soil thoroughly. According to combined analysis of variance, effect of year was significant only on silique number per plant, respiration rate, and iron (Fe) content. Also results indicated that N fertilizer increased plant height, silique number per plant, seed number per silique, 1000-seed weight, and finally seed yield. Similarly, zeolite increased yield and yield components whereas plant height was not affected by zeolite in the second year. Oil yield decreased due to N and zeolite application. In addition, photosynthesis and respiration improved on account of N and zeolite treatments. Nitrate reductase activity significantly was promoted by N and zeolite. Furthermore, micro- and macroelements were affected by N or zeolite application, so that N and zeolite decreased P content whereas N increased N, K, Fe, and zinc. In general our results demonstrated that zeolite application can increase canola growth and production, which may be through increasing N-use efficiency and improving soil physical characteristics.  相似文献   

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