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1.
A study was carried out to compare the effects of treating wheat (Triticum aestivum) and Italian ryegrass (Lolium multiflorum) with atrazine and fluorodifen. The herbicides interfered with photosynthesis and dark respiration, depending on the species. Atrazine decreased photosynthesis in both species and dark respiration in wheat, while fluorodifen caused decrements of photosynthetic activity of wheat. Antioxidant enzymes, such as ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR), were generally more active in untreated and treated wheat with respect to Italian ryegrass, which explains why oxidative damage, expressed as malondialdehyde (MDA) content, was only found in ryegrass. Investigations on the activity of herbicide-detoxifying enzyme, glutathione S-transferase (GST), and on the accumulation and persistence of the herbicides in the plants showed higher detoxification rates in wheat than in the grass.  相似文献   

2.
The action of safener benoxacor on the detoxification of terbuthylazine (TBA) in Zea mays and Festuca arundinacea was ascertained by the investigation of the effects of benoxacor on the activity of glutathione-S-transferases (GSTs) in the shoots of the two plant species. TBA treatment generally reduced GST activity toward 1-chloro-2,4-dinitrobenzene (CDNB) in corn and did not affect the enzyme activity in festuca. When applied alone, benoxacor stimulated GST activity in both plants; however, when it was applied in mixture with TBA, generally, an enhancement of the enzyme activity was found in corn but not in festuca in comparison with the respective TBA-treated samples. The enhancement of GST activity in response to the benoxacor treatment in both corn and festuca resulted to be concomitant with decreases in apparent K(M) in both the plant species, with V(max) unaffected, and with an increased expression of proteins having molecular masses in the characteristic range of plant GSTs. After the benoxacor treatment, increased GST activity toward TBA as a substrate was observed in both corn and festuca. As a consequence, lesser amounts and persistence of TBA residues were found in shoots of corn and festuca treated with the TBA and benoxacor mixture compared to TBA-only-treated samples. Therefore, benoxacor enhances TBA detoxification in both corn and festuca; the induction of detoxifying activity in a nondomesticated grass is discussed in view of its use in vegetating buffer strips around crops to prevent TBA pollution.  相似文献   

3.
采用沙培方法,利用生理生化试验及半定量PCR方法,研究了保护剂HN对玉米ALS、GSTs活性及GSTs的mRNA表达量的影响。结果表明,保护剂对6个玉米品种的ALS、GSTs均具有诱导作用,但对不同品种的诱导增加百分率却不同。对氯嘧磺隆敏感的玉米东甜3号的GSTs诱导增加百分率达到59.18,对其ALS的诱导倍数为叶部1.29倍,根部2.30倍;对氯嘧磺隆耐性较高的玉米屯玉88GSTs诱导增加百分率为19.26,其ALS的诱导倍数为叶部1.07倍,根部2.07倍。氯嘧磺隆和保护剂均可以诱导玉米GSTsmRNA的相对表达量的增加,保护剂的诱导作用更强。  相似文献   

4.
为探究安全剂与除草剂复配施用对除草剂药害的缓解以及对糜子田土壤酶活性、根系活性氧代谢和糜子生长发育的影响。于2019年5~10月在陕西省榆林市小杂粮试验示范站进行试验,选用糜子品种''榆糜2号''为试验材料,选取苗前除草剂:谷友(10%单嘧磺隆,2.4 kg/hm2)与3种安全剂:芸苔素(300 mL/hm2)、赤霉素(300 mL/hm2)、奈安(1.2 kg/hm2)复配使用,设置清水不除草对照与人工除草对照。测定杂草鲜重防效、药害指数、根际土壤酶活性、糜子根系抗氧化酶活性与丙二醛含量及糜子农艺性状与产量。结果表明:1)芸苔素、赤霉素、奈安与单嘧磺隆复配后药害指数显著下降,分别降低了20.27%、21.63%、20.94%;2)单嘧磺隆处理(H1)的土壤蔗糖酶、脲酶活性在施药后7~42 d时相较于处理CK1被显著抑制,活性抑制率随时间降低,添加安全剂后土壤蔗糖酶和脲酶活性显著提升,抑制率显著降低;3)与单施除草剂相比,安全剂复配施用的糜子根系SOD活性在施药后14~28 d时显著升高;CAT活性显著降低;MDA含量明显降低;4)单嘧磺隆导致糜子株高、穗长、主穗质量降低,安全剂复配施用减少了除草剂的不利影响,其中单嘧磺隆与赤霉素复配施用产量最高,达5 035 kg/hm2,较CK1增产1 114 kg/hm2,较单施单嘧磺隆处理的增产1 061 kg/hm2。安全剂与单嘧磺隆复配使用能延缓单嘧磺隆对糜子根际土壤酶活性的抑制,提高土壤蔗糖酶、脲酶活性,提高糜子根系SOD活性,减缓了药害胁迫造成的膜脂过氧化作用,减少细胞膜系统的损伤,延缓了根系衰老进程,提高了糜子的株高、茎粗、穗长、主穗质量及产量。其中赤霉素与单嘧磺隆复配使用在缓解除草剂药害,促进糜子增产方面效果较好。  相似文献   

5.
The competitive antagonist hypothesis for safeners and herbicides was investigated by studying the 3D similarity between 28 safener and 20 herbicide molecules in their putative biologically active, low-energy conformations using comparative molecular field analysis (CoMFA). In addition, CoMFA provided information about the structural requirements for the interactions of safeners and herbicides with a proteinaceous component (SafBP) isolated from etiolated corn seedlings. Statistically significant CoMFA models have been developed for the united and separate safener and herbicide molecule sets using retrospective binding affinity data of the ligands measured at the SafBP receptor. The predictive power of the models was characterized by squared cross-validated correlation coefficients (q(2)) of 0.708, 0.564, and 0.4000 for the united safener plus herbicide set, the safener set, and the herbicide set, respectively. The CoMFA results support the competitive antagonist hypothesis between certain types of safeners and herbicides. The findings suggest that structural similarity between these two classes of agrochemicals is a useful guide in the design of new safeners.  相似文献   

6.
Variable practical results have been observed for no-till (NT) drilling of grasslands in Galicia, northwest Spain. One of the possible explanations to this erratic behaviour could be the influence of different types of stubble on drill performance and grassland emergence. Because the rotation of silage corn (Zea mays L.) with grassland is the most popular rotation in the Galician dairy farms at present, NT drilling of Italian ryegrass on corn stubble and ryegrass stubble was evaluated. Results were compared with NT drilling after shredded stubble and with conventional drilling (with tillage) for 5 years. Annual ryegrass establishment, biomass production, and forage production were measured each year. Treatments considered were: (1) NT on shredded ryegrass stubble; (2) NT on ryegrass stubble; (3) NT on corn stubble; (4) NT on shredded corn stubble; (5) conventional tillage (CT). Better plant stands and more forage production were obtained on the CT and NT-shredded treatments. Allelopathic effects were not observed, and the differences in plant stands among treatments could be caused by the physical effects of stubble and not by its physiological effects. The shredding operation improved plant stands and forage production of Italian ryegrass, which were not influenced by the type of stubble. Years with abundant rainfall negatively affected crop development, which was more evident in NT treatments. NT methods had advantages in terms of timeliness and low economic costs, as compared to CT.  相似文献   

7.
盐胁迫对黑麦草幼苗生长的影响及磷肥的缓解作用   总被引:8,自引:0,他引:8  
杨晓英  杨劲松 《土壤通报》2005,36(6):899-902
采用盆栽试验和生理生化分析方法研究了盐胁迫对黑麦草幼苗生长的影响以及施用磷肥(过磷酸钙)对盐胁迫下黑麦草幼苗生长的缓解作用。结果表明,盐胁迫下黑麦草幼苗干物质积累下降;增施磷肥能促进黑麦草幼苗生长,增加干物质积累,增强黑麦草对Na+、K+吸收的选择性,促进K+的吸收和向叶片运输;能提高叶片叶绿素含量,增强叶片净光合速率和气孔导度,增加可溶性蛋白、可溶性糖及脯氨酸含量,从而增强黑麦草幼苗对盐胁迫的适应能力。  相似文献   

8.
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   

9.
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   

10.
锌胁迫对重金属富集植物黑麦草养分吸收和锌积累的影响   总被引:20,自引:2,他引:20  
采用土培根袋试验研究了锌胁迫对重金属富积累植物黑麦草4个品种生长,N、P、K养分及Zn吸收积累的影响。结果表明,Zn在一定范围内(0~520mg/kg)促进了黑麦草生长,RTI(根系耐性指数)≥1.0(0~520mg/kg Zn^2+)。在Zn^2+≤260mg/kg(根系)或Zn^2+≤520mg/kg(地上部)时,黑麦草吸收N、P、K并未受到抑制。植株地上部和根系最大N、P、K含量大多出现在生物量最大或次高的260,520mg/kg Zn^2+处理中。黑麦草植株Zn含量随Zn胁迫的增加而增加,以泰德植株Zn含量和对Zn的转运率最高(其植株Zn地上部最大含量为583.9mg/kg DW,加Zn处理的S/R〉1)。  相似文献   

11.
This study evaluated the expression of human cytochrome P450 genes CYP1A1, CYP2B6, and CYP2C19 in rice plants (Oryza sativa cv. Nipponbare) introduced using the plasmid pIKBACH. The transgenic rice plants (pIKBACH rice plants) became more tolerant toward various herbicides than nontransgenic Nipponbare rice plants. Rice plants expressing pIKBACH grown in soil showed tolerance to the herbicides atrazine, metolachlor, and norflurazon and to a mixture of the three herbicides. The degradation of atrazine and metolachlor by pIKBACH rice plants was evaluated to confirm the metabolic activity of the introduced P450s. Although both pIKBACH and nontransgenic Nipponbare rice plants could decrease the amounts of the herbicides in plant tissue and culture medium, pIKBACH rice plants removed greater amounts in greenhouse experiments. The ability of pIKBACH rice plants to remove atrazine and metolachlor from soil was confirmed in large-scale experiments. The metabolism of herbicides by pIKBACH rice plants was enhanced by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, pIKBACH rice plants may become useful tools for the breeding of herbicide-tolerant crops and for phytoremediation of environmental pollution by organic chemicals.  相似文献   

12.
In this paper, the effects of earthworms on the growth and Zn uptake of ryegrass and Indian mustard in artificially Zn-contaminated soils were studied. Earthworm inoculation increased plant shoot biomass by 29–83% for ryegrass and by 11–42% for Indian mustard, respectively, as compared to the treatments without earthworms, while the roots’ biomass of both plants were increased much more than their corresponding shoots. Earthworms also increased shoot Zn concentrations in both ryegrass and Indian mustard, although the increases in ryegrass did not show significant difference. Except for soil without Zn contamination, the Zn contents of both ryegrass and Indian mustard roots were significantly increased by earthworm addition. Generally, Zn contents of roots were relatively higher than those of shoots for both plants, which were independent of earthworms inoculation. Earthworm increased soil bioavailable metal (diethylenetriamine-pentaacetic acid–Zn) (DTPA-Zn) concentrations, which resulted in a direct increase in Zn uptake by the plants, since a significant correlation was observed between the DTPA–Zn contents and plant Zn uptake. However, the main reason for the increase in plant Zn uptake under earthworm inoculation was probably the increase in dry matter production stimulated by earthworms.  相似文献   

13.
通过营养液培养,重点研究了不同浓度镉(Cd)胁迫下,中双9号冬油菜(Brassica napus L.)幼苗体内生理生化及微量元素(Fe、Mn、Zn、Cu)含量的变化特征,目的是进一步阐明Cd胁迫对油菜生长产生毒害的作用机理。结果发现,Cd胁迫显著抑制了油菜幼苗的生长,植株根系和地上部干重随着Cd浓度的升高而显著降低;油菜幼苗叶片中光合色素含量也随着Cd浓度的升高而显著降低;油菜幼苗根系和地上部4种微量元素浓度也随着Cd浓度的升高发生了显著变化;同时,油菜幼苗体内抗氧化酶(SOD、POD和CAT)活性随着Cd浓度的升高表现出先显著升高后显著降低的趋势。这些结果表明,外源Cd胁迫通过降低油菜幼苗光合色素含量、抑制植株光合作用,引起幼苗体内养分代谢紊乱,诱导产生氧化胁迫等抑制了油菜幼苗的生长。研究还发现,中双9号油菜幼苗地上部Cd浓度和Cd富集量显著低于根系,中双9号应该属于低吸收Cd的冬油菜品种。  相似文献   

14.
  【目的】  硫是植物生长发育过程中所必需的营养元素,缺硫会阻碍植物生长发育,研究外源谷胱甘肽 (GSH) 对缺硫胁迫下小白菜GSH代谢的影响,为利用外源GSH减轻缺硫胁迫对植物造成的伤害提供理论依据。  【方法】  以小白菜为试验材料,采用营养液栽培方法,设正常供硫并喷施蒸馏水对照 (CK)、缺硫喷施蒸馏水(H2O)、缺硫喷施25 mg/L的还原型谷胱甘肽 (GSH) 和缺硫喷施25 mg/L的氧化型谷胱甘肽 (GSSG) 4个处理。喷施处理在缺硫培养17 天时进行,在喷施处理后0、2、4、8、24 h,取样测定小白菜GSH合成关键基因BcGSH1表达量;在喷施处理0、24、48、72 h后,取样测定γ-谷氨酰半胱氨酸合成酶 (γ-ECs) 活性、内源GSH和GSSG含量及GSH还原酶 (GR)、GSH过氧化物酶 (GPx) 和GSH硫转移酶 (GST) 活性。  【结果】  与CK相比,缺硫显著降低了小白菜BcGSH1表达量、GSH含量及γ-ECs、GR和GST活性,提高了GPx活性;外源喷施GSH能够显著提高缺硫胁迫下小白菜BcGSH1表达量、GSH含量及γ-ECs、GR、GPx和GST活性;外源喷施GSSG后,缺硫胁迫下小白菜GSH含量、GSSG含量和γ-ECs活性仅短暂上升,GR和GST活性显著增强,GPx活性最终减弱。  【结论】  缺硫胁迫下,小白菜能够吸收外源喷施的GSH和GSSG,并诱导GSH合成酶活性增强,外源喷施GSH还会诱导细胞内GSH代谢3个关键酶GR、GPx和GST活性增强,显著缓解缺硫胁迫对小白菜造成的损伤;而外源喷施GSSG则诱导GR和GST活性增强,GPx活性降低,维持细胞不被继续氧化,一定程度上缓解因缺硫胁迫对机体造成的损伤。  相似文献   

15.
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   

16.
Glutathione (GSH) can be found in plants in considerable amounts. It is very important for numerous metabolic functions and for the detoxification of xenobiotics. The present study was carried out to show the inducibility of glutathione S-transferase (GST) isozymes in spruce by various substrates commonly used to assay GST activity, Inducers were: chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), para-nitrobenzoylchloride (pNBC), fluorodifen and n-ethylmaleinimide (NEM). Conjugation of CDNB was enhanced by the xenobiotics ranking in the order: CDNB > fluorodifen > pNBC > NEM > DCNB.  相似文献   

17.
The morphology and length of roots and shoots of tomato (Lycopersicon esculentum Mill.) seedlings grown on a nutrient medium for fourteen days in a controlled environment chamber were apparently not affected, whereas the dry matter content of roots was significantly enhanced when 200 mg L?1 of humic acid (HA) isolated from either a non-amended soil or a sewage-sludge-amended soil was present in the nutrient medium. In contrast, the HA-like fraction isolated directly from the sewage sludge caused, under the same conditions, extensive alterations of tomato morphology and a significant reduction of the length and dry weight of both shoots and roots. The presence in the nutrient medium of the herbicides alachlor or imazethapyr at concentrations of 1 and 0.01 mg L?1, respectively, caused a marked decrease of tomato root and shoot length and dry weight. Differently, the herbicide rimsulfuron at a concentration of 0.01 mg L?1 produced a slight decrease in shoot and root length and a slight increase in their dry weight. A combination of 200 mg L?1 soil HA and each of the herbicides alachlor, rimsulfuron and imazethapyr at concentrations of 1, 0.01 and 0.01 mg L?1, respectively, in the nutrient medium attenuated the growth depression of tomato shoots and roots observed in the presence of the herbicide alone. However, the simultaneous presence of sewage sludge HA and any herbicide in the nutrient solution caused negative synergistic effects on tomato growth. The volume of nutrient solution and the amount of electrolytes taken up by tomato plants during the growth experiments correlated highly significantly with the total plant dry weight. Tomato seedlings induced a pH decrease in the nutrient medium in all treatments except in those where sludge-HA was present, either alone or in combination with any herbicide.  相似文献   

18.
Catch crop strategy and nitrate leaching following grazed grass-clover   总被引:1,自引:0,他引:1  
Cultivation of grassland presents a high risk of nitrate leaching. This study aimed to determine if leaching could be reduced by growing spring barley (Hordeum vulgare L.) as a green crop for silage with undersown Italian ryegrass (Lolium multiflorum Lam.) compared with barley grown to maturity with or without an undersown conventional catch crop of perennial ryegrass (Lolium perenne L.). All treatments received 0, 60 or 120 kg of ammonium‐N ha?1 in cattle slurry. In spring 2003, two grass‐clover fields (3 and 5 years old, respectively, with different management histories) were ploughed. The effects of the treatments on yield and nitrate leaching were determined in the first year, while the residual effects of the treatments were determined in the second year in a crop of spring barley/perennial ryegrass. Nitrate leaching was estimated in selected treatments using soil water samples from ceramic cups. The experiment showed that compared with treatments without catch crop, green barley/Italian ryegrass reduced leaching by 163–320 kg N ha?1, corresponding to 95–99%, and the perennial ryegrass reduced leaching to between 34 and 86 kg N ha?1, corresponding to a reduction of 80 and 66%. Also, in the second growing season, leaching following catch crops was reduced compared with the bare soil treatment. It was concluded that the green barley/Italian ryegrass offers advantages not only for the environment but also for farmers, for whom it provides a fodder high in roughage and avoids the difficulties with clover fatigue increasingly experienced by Danish farmers.  相似文献   

19.
Glutathione S-transferases (GSTs) (EC 2.5.1.18) are ubiquitous enzymes that have a defined role in xenobiotic detoxification, but a deeper knowledge of their function in endogenous metabolism is still lacking. In this work, we isolated the cDNAs as well as the genomic clones of orange GSTs. Having considered gene organization and homology data, we suggest that the isolated GST gene is probably involved in the vacuolar import of anthocyanins. We also found that the blood and blond orange GSTs shared the same nucleotide sequences, but as expected, the GST expression in the nonpigmented orange cultivar [Citrus sinensis L. (Osbeck)] (Navel and Ovale) was strongly reduced as compared to that of the pigmented orange (Tarocco). Interestingly, in the crude extracts of pigmented orange fruits, the GST activity was reproducibly detected by providing either 1-chloro-2,4 dinitrobenzene (CDNB) or cyanidin-3-O-glucoside (C-3-G) as substrates; moreover, we have shown that cyanidin-3-O-glucoside acted as a powerful competitive inhibitor of 1-chloro-2,4 dinitrobenzene conjugation to reduced glutathione (GSH) in the pigmented orange, confirming that this molecule might easily bind to the active site of the enzyme and functions as a putative substrate. In addition, we have reported here the successful in vitro expression of orange GST cDNAs leading to a GST enzyme that is active against cyanidin-3-O-glucoside, thus suggesting the probable involvement of the isolated gene in the tagging of anthocyanins for vacuolar import. This last result will help to study the kinetic and structural properties of orange fruit GST avoiding time-consuming protein purification procedures.  相似文献   

20.
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   

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