丁草胺对水稻分蘖影响的研究

通过盆栽试验,探讨了丁草胺施药量、施药时期、施药时水层深度对水稻分蘖的影响。结果表明:在供试水稻品种中施用丁草胺会降低其分蘖质量;在同一品种中,随施药量增加,分蘖数量减少;缓苗后施药比缓苗前施药的水稻分蘖多;施药时保持4 cm水层(未没过心叶)对水稻分蘖的影响小于保持8 cm水层(没过心叶)。初步明确了不同水稻品种对丁草胺的敏感性不同,本试验中的东农419水稻对丁草胺的敏感性高于绥粳4号。     

干旱胁迫对不同小麦品种花后旗叶生理特性的影响

在防雨旱棚池栽条件下研究了干旱胁迫对不同小麦品种旗叶某些生理特性的影响。结果表明,干旱胁迫条件下,小麦开花后旗叶的相对含水量、可溶性蛋白质含量和保护酶系统SOD、CAT和POD活性均降低,膜脂过氧化产物MDA含量升高,产量也随之下降。与水浇地品种相比,旱地品种青麦6号和鲁麦21旗叶的相对含水量、可溶性蛋白质含量相对较高且下降缓慢,SOD、CAT和POD活性降低的幅度比较缓和,随着干旱胁迫MDA含量继续积累的速度缓慢,产量及产量构成因素降低的幅度小。青麦6号与鲁麦21相比,旗叶的相对含水量、可溶性蛋白质含量和SOD、CAT、POD活性较高,MDA含量较低并且最终产量较高,说明青麦6号在干旱胁迫条件下能保持一个相对较优的生理状态,其代谢功能和抗旱能力较强。     

天然芸苔素内酯缓解胺苯磺隆对后茬水稻药害的作用机理初探

通过测定天然芸苔素内酯对水稻幼苗谷胱甘肽(GSH)含量、谷胱甘肽-S-转移酶(GST)活性以及在离体和活体条件下对水稻幼苗乙酰乳酸合成酶(ALS)活力的影响,研究天然芸苔素内酯减轻胺苯磺隆对水稻药害的作用机理。结果表明,其作用机理与水稻幼苗GSH含量、GST活性变化没有太大相关性,可能与其能间接激活水稻幼苗ALS活力有较大相关。     

3种除草剂对寒地水稻的生理效应研究

为了筛选出适宜在寒地粳稻本田使用的除草剂,采用田间小区试验进行了3种除草剂2个施用剂量对水稻生理指标影响的试验,结果表明:3种除草剂对水稻氮代谢、抗逆性、形态特征和产量构成等影响各异,与清水对照比,30%莎稗磷EC显著增加水稻前期MDA含量,并显著降低水稻前期的NR活性、收获期有效分蘖数、穗长和小穗数;60%丁草胺EC和50%丙草胺EC高剂量处理效果相近,均对水稻体内的NR活性、MDA含量影响较小,但显著增加了穗粒数和穗粒重。粳稻本田施用60%丁草胺EC和50%丙草胺EC高剂量处理效果好于30%莎稗磷EC,与后者相比,施用60%丁草胺EC和50%丙草胺EC高剂量可诱导植株的NR、GS、CAT活性显著增加,而MDA含量显著降低,这种效果一直延续到生长后期,使穗长、小穗数、穗粒重及稻谷产量均得到显著增加。     

光合细菌复配柠檬酸铜对移栽稻田水绵防效的研究

水绵是对水稻危害较重的低等藻类,本研究采用盆栽试验方法研究沼泽红假单胞菌复配柠檬酸铜对水绵的鲜重防效及施用后水绵中Mg²⁺、Fe²⁺、叶绿素含量和抗逆酶活性,同时测定了施用后水稻生长指标及抗逆酶活性。结果表明,施药后28 d,沼泽红假单胞菌复配柠檬酸铜对水绵的鲜重防效达92.17%,显著高于沼泽红假单胞菌或柠檬酸铜单独施用。与对照相比,水绵叶绿素、Mg²⁺和Fe²⁺含量分别显著降低60%,43%和39%,POD和SOD活性分别显著降低72%和71%,MDA含量显著升高50%。水稻叶片POD和SOD活性分别显著增加44%和104%,MDA含量显著降低51%,单株鲜重显著增加43%,分蘖数显著增加65%,株高增加5%。综上,沼泽红假单胞菌复配柠檬酸铜对水绵防效显著且对水稻安全,水绵叶绿素合成受到抑制和细胞膜过氧化作用是其对水绵防除的重要作用机理。     

重金属Cd及施肥对马铃薯抗氧化酶系统的影响

采用土培盆栽方法,以两个马铃薯品种克新一号和费乌瑞它为材料,研究不同浓度Cd胁迫下对马铃薯抗氧化酶系统的影响以及施肥对受Cd胁迫马铃薯的调控。结果表明,随着Cd处理浓度的提高,两个马铃薯品种叶片中SOD、CAT活性呈先上升后下降的趋势,并与对照成显著性差异。费乌瑞它马铃薯叶片中POD活性也呈先上升后下降的趋势。克新一号随着Cd处理浓度的升高,叶片POD活性呈先上升后下降再上升的趋势。随着Cd处理浓度的升高,两个品种马铃薯叶片中MDA、脯氨酸含量则成明显上升趋势。在Cd处理浓度为10mg/kg时,施用有机肥使两个品种马铃薯叶片SOD、POD活性降低,克新一号马铃薯叶片CAT活性降低。施用无机肥对两个品种马铃薯叶片SOD、CAT活性无显著性影响。与施用无机肥相比,施用有机肥对Cd胁迫马铃薯的缓解效果更明显。     

作保灵(TNA)对水稻的保护作用及作用机理研究

研究了作保灵对水稻的保护作用及对氯嘧磺隆的解毒机理。当土壤中氯嘧磺隆残留量为10μg· kg-1时 ,水稻生长发育受到影响,并随着氯嘧磺隆残留量的增加,对水稻的抑制作用明显增强。作保灵 50 mg· kg-1浸种或 200mg· kg-1叶喷都能缓解氯嘧磺隆对水稻产生的药害。作保灵能明显提高水稻体内谷胱甘肽转移酶(GST)活性,增加谷胱甘肽(GSH)、多酚及脯氨酸含量,诱导氯嘧磺隆与谷胱甘肽、多酚进行轭合,从而对氯嘧磺隆进行解毒。     

水分胁迫对不同品种甜高粱幼苗保护酶活性等生理特性的影响

以两个甜高粱品种为材料,研究不同浓度PEG-6000渗透溶液对甜高粱幼苗保护酶活性等生理特性的影响,比较不同品种间的抗旱性差异。结果表明:10%、20%PEG胁迫下两个品种甜高粱幼苗叶片相对含水量下降,质膜相对透性、丙二醛及脯氨酸含量增大,其中农家品种变幅较大;随着PEG胁迫浓度的增加,两个品种叶片还原型谷光苷肽(GSH)含量降低,20%PEG胁迫下甜新2号GSH含量高于农家品种;两种PEG浓度处理下,甜新2号叶片抗氧化酶(APX、POD、SOD、CAT)活性高于农家品种。综合分析表明,相对于农家品种,甜新2号具有较强的抗旱性。     

灌水方式与水稻品种抗稻纵卷叶螟程度的关系

通过不同灌水方法测定不同水稻品种叶片的含水率,结果证明水稻品种抗虫性随叶片含水率增高而降低。抗性品种长期灌水保持水层后,叶片含水率增高,抗性降低,幼虫成活率提高,生长速度加快。只有在保持湿润灌水的情况下才表现抗性。为发挥抗虫品种的作用,提出推广间歇灌水或湿润灌水的方法。     

3种除草剂对水稻旱直播阔叶杂草防效及安全性研究

为明确不同除草剂茎叶处理对旱直播水稻田旱生阔叶杂草防除及安全性的影响,采用随机区组试验设计,选用30% 2,4-滴丁酸钠盐AS、84%氯酯磺草胺WG、480 g/L灭草松AS 3种除草剂在水稻4叶期、5叶期施用,施药后每间隔7 d测定杂草株防效、鲜重防效和水稻目测药害,同步测定水稻生长指标和抗逆酶活性。结果表明:30% 2,4-滴丁酸钠盐AS 900.0 g/hm2在水稻4叶期的杂草防效最佳,第28天杂草株防效及鲜重防效仍可达93.55%和96.42%,且对大龄鸭跖草防效显著,施药后水稻生长与人工除草相比无显著差异。叶片SOD、POD活性和MDA含量均先升后降,至施药后28 d恢复正常。30% 2,4-滴丁酸钠盐AS 900.0 g/hm2可高效防除阔叶杂草,该药剂在水稻4叶期和5叶期施用对旱直播水稻安全。     

Protective effect of vitamin C against chlorpyrifos oxidative stress in male mice

Pesticides may induce oxidative stress leading to generate free radicals and alternate antioxidant or oxygen free radical scavenging enzyme system. This study was conducted to investigate the acute toxicity of chlorpyrifos toward male mice and the oxidative stress of the sub-lethal dose (1/10 LD₅₀) on the lipid peroxidation level (LPO), reduced glutathione content (GSH) and antioxidant enzymes; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glucose-6-phosphate dehydrogenase (G6PD), and glutathione-S-transferase (GST) activities. Also, the protective effects of vitamin C (200 mg/kg body weight, bw) 30 min before or after administration of chlorpyrifos were investigated. The results demonstrated that the LD₅₀ value of chlorpyrifos was 134.95 mg/kg bw. The oral administration of 13.495 mg/kg chlorpyrifos significantly caused elevation in LPO level and the activities of antioxidant enzymes including CAT, SOD and GST. However, GPx activity remained unchanged, while the level of GSH and G6PD activity were decreased. Vitamin C treatment to chlorpyrifos intoxicated mice decreased LPO level and GST activity, normalized CAT, SOD and G6PD activities, while GSH content was increased. We conclude that vitamin C significantly reduces chlorpyrifos-induced oxidative stress in mice liver and the protective effect of the pre-treatment with vitamin C is better than the post-treatment.     

农艺措施和除草剂用量对化感稻产量及杂草生物量的影响

为实现水稻生产减施除草剂的目标,将化感材料与农艺措施相结合取得对稻田杂草有效控制的效果,田间采用再裂区试验法研究了化感稻3号和N两优201两个水稻化感材料和非化感材料五山丝苗在不同水分管理、移栽密度和除草剂不同用量下,对水稻产量和田间杂草生物量的影响。结果表明:无论早季稻田还是晚季稻田,施用常规除草剂量的小区杂草生物量均为0,施用常规剂量50%除草剂且仅在孕穗期晒田的小区和常规密度小区有少量杂草发生。不施除草剂的水稻材料小区杂草生物量依次为化感稻3号N两优201五山丝苗。移栽后75 d,不施除草剂的小区相同水稻材料孕穗期不晒田比晒田处理、高密度比常规密度处理的杂草生物量小。早季稻田不晒田和高密度提高了水稻的产量,晚季稻田则相反。化感材料化感稻3号和N两优201在田间的抑草效果较五山丝苗要好。在水稻生产中,水稻化感材料结合农艺措施,可以实现水稻不减产,田间杂草得到有效控制,除草剂量减50%的目标。     

粉垄耕作对宁南旱地马铃薯生理特性及产量的影响

设置传统耕作(CK)、深耕(DT)、粉垄30 cm(F30)和粉垄50 cm(F50) 4种耕作措施进行试验,分析了粉垄耕作对马铃薯生理特性、叶片淀粉合成关键酶活性、土壤水分含量及马铃薯产量的影响。结果表明:粉垄耕作显著提高了土壤含水量,其中F50处理土壤含水量最高,分别在0～20 cm和20～40 cm土层较处理F30、DT、CK高出0.66%～1.12%、0.74%～2.22%、1.26%～1.41%;相关分析表明,土壤含水量与丙二醛(MDA)、脯氨酸(Pro)和可溶性糖含量呈负相关关系,与超氧化物歧化酶(SOD)、过氧化氢酶(CAT)呈正相关关系;粉垄耕作降低了丙二醛(MDA)、脯氨酸(Pro)和可溶性糖的含量,不同生育时期F50和F30分别较CK降低了13.19%～20.35%、25.19%～41.11%、13.75%～33.33%和12.75%～22.88%、38.35%～86.39%、14.29%～36.36%;粉垄耕作提高了超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、淀粉合成酶(GBSS)、淀粉磷酸合成酶(SSS)和淀粉分支酶(SBE)活性,不同生育时期F50和F30分别较CK提高了8.73%～14.94%、17.24%～31.07%、14.94%～39.76%、42.5%～81.23%、35.43%～61.26%和8.56%～14.61%、19.56%～36.32%、14.86%～36.16%、36.54%～75.73%、26.17%～53.27%;粉垄耕作显著提高了马铃薯产量,与CK相比,F50和F30分别显著提高32.09%、24.60%;通过灰色关联度分析得出,粉垄耕作处理F30表现较优,除苗期外等权关联度和加权关联度位次都为第一。在生产中建议推广的耕作措施为粉垄30 cm(F30)。     

环境条件对除草剂莎稗磷降解的影响

环境条件影响莎稗磷在土壤中的降解速度 :随着土壤温度的升高和含水量的增加 ,莎稗磷降解速度加快 ,在温度为 2 0、30和 4 0℃下 ,经过 10 d,莎稗磷的降解率分别为10 .4 %、2 6 .7%和 37.6 % ;在相对含水量为 30 %～ 110 %的土壤中 ,15d后莎稗磷降解 4 5.0 %～ 6 8.4 %。土壤中有机质能促进莎稗磷的降解 ,在有机质含量为 3.35%和 0 .55%的两种土壤中 ,莎稗磷的半衰期分别为 11d和 15d。莎稗磷在碱性土壤中比在酸性土壤中降解快 ,在偏酸性 (p H值为 6 .0 1)土壤中的半衰期为 2 2 d,在偏碱性 (p H值为 7.98)土壤中半衰期为 15d.     

Residual phytotoxic activity of pethoxamid in soil and its concentration in soil water under different soil moisture conditions

The relationship between the residual phytotoxic activity of pethoxamid (2-chloro- N -[2-ethoxyethyl]- N- [2-methyl-1-phenyl-1-propenyl] acetamide) on rice ( Oryza sativa cv. Kiyohatamochi) seedlings and its behavior in soil was investigated under different moisture conditions. The phytotoxic activity of pethoxamid on the shoot growth of rice seedlings in soil was higher in 80% soil moisture content than in 70% and 60% soil moisture contents. The phytotoxic activity in soil in 70% and 80% soil moisture conditions decreased with the increasing time after application, but the phytotoxic activity was slight in 50% soil moisture conditions at any given time after application. The residues of pethoxamid in soil water, the amount adsorbed on soil solid, and the amount in total soil was reduced with the time after application in a similar manner among these soil moisture conditions. The residual phytotoxic activity of pethoxamid on the shoot growth of rice seedlings in soil was more highly correlated with the concentration in soil water than with the amounts adsorbed on soil solid and in total soil. The partition coefficients between the amounts of pethoxamid adsorbed on soil solid and its concentration in soil water were similar among the soils with different moisture conditions at each day, and the partition coefficient increased with the time after application. These results suggested that the residual phytotoxic activity of pethoxamid in soil depends on the decreasing concentration of pethoxamid in soil water with time, except in low soil-moisture conditions, which were insufficient for seedling growth.     

Biochemical and histological hepatic changes of Nile tilapia Oreochromis niloticus exposed to carbaryl

The purpose of this study was to evaluate biochemical and morphological responses induced by carbaryl in the liver of Nile tilapia (Oreochromis niloticus) exposed during 21 days to sublethal concentrations (0.25 and 0.5 mg L⁻¹), testing also recover for 14 days in clean water, after 14 days exposure. The activities of the following enzymes were measured: superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione reductase (GR), and reduced (GSH) and oxidized glutathione (GSSG). Globally, our data showed that exposure to carbaryl decreased the SOD, CAT, GR, and GST activities, except for the SOD and GST activities after 14 days exposure to 0.25 mg L⁻¹. In contrast, after 14 days exposure the GR activity of the hepatic tissue from carbaryl-treated fish showed significant elevation in relation to the control. When fish were left to recover, a positive response was seen in the GSH and GSSG contents. The results of the recovery group suggest that the toxicity produced by carbaryl is reversible to some extent within 15 days. The liver histological analysis showed differences between fish concerning the cellular vacuolization degree (VD) of the hepatocytes. In fish exposed to carbaryl it was observed an increasing hepatocellular basophilia. No other histological alterations were observed when fish was exposed to carbaryl, except a few necrotic foci at day 7. The sections stained with PAS reaction showed that the vacuolization was always not due to glycogen deposits, thus suggesting lipid accumulation. The combined increased basophilia and glycogen depletion is a common, although non-specific, liver response to many toxicants. In short, this work shows a relation between histological and biochemical changes in liver and carbaryl exposure. The effects of carbaryl were observed at different concentrations.