盐胁迫对海岛棉幼苗生长的影响

采用盆栽试验方法,研究了新海16号、新海20号、新海24号、新海25号、新海28号、新海34号和新海35号等7个海岛棉品种在盐胁迫(0.6%NaCl)下幼苗生长情况、光合特性等,为海岛棉栽培管理及耐盐品种的选育提供一定的理论依据。结果表明,0.6%NaCl盐胁迫下,种子出苗率、株高、鲜重、干重、第一片真叶叶绿素含量(Chl)、净光合速率(Pn)、胞间CO_2浓度(Ci)、气孔导度(Gs)和蒸腾速率(Tr)均有所下降;而植株含水量、可溶性糖含量(SS)、可溶性蛋白质(SP)和丙二醛含量(MDA)均增加。同等盐胁迫条件下,新海24号、新海34号、28新海号、新海35号与其余3个品种相比,具有较低的植株含水量和丙二醛含量,均保持较高的可溶性糖含量和可溶性蛋白质含量,表现出较好的耐盐性。本研究发现,0.6%NaCl盐胁迫对海岛棉种子出苗影响较小,对幼苗株高、鲜重、干重和植株含水量影响较大。海岛棉幼苗叶片净光合速率降低可能是气孔限制因素所引起的。海岛棉品种在0.6%NaCl盐胁迫下基本上都表现出较好的耐盐性,但对新海20号的影响较大。     

Herbage mass, nutritive value and palatability of five grass weeds for cattle in the northern Tohoku region in Japan

The objective of this grazing study was to determine the herbage mass, nutritive value and palatability of five grass weed species ( Eleusine indica (L.) Gaertn, Paspalum thunbergii Kunth, Digitaria ciliaris (Retz.) Koeler, Setaria glauca (L.) Beauv. and Echinochloa crus-galli (L.) Beauv. var. crus-galli ) as feeds compared with six forage cultivars ( Lolium perenne L., two Lolium multiflorum cultivars and three Echinochloa crus-galli (L.) Beauv. cultivars). The herbage mass of weed species, with the exception of S. glauca , was most prevalent in August. The total amounts of herbage mass of weed species (except E. indica ) were close to those of the Lolium cultivars, but lower than those of the E. crus-galli cultivars. During the summer, weed species (except E. crus-galli var. crus-galli ) contained favorable levels of total digestible nutrients (TDN), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and mineral contents, and exhibited adequate calcium (Ca):phosphorus (P) ratios of 1:2. All weed species had the recommended ratios of potassium (K):(Ca + [magnesium] Mg) < 2.2:1. By autumn, the summertime levels of nutritive values (TDN, CP, ADF and NDF) in the weed species had severely deteriorated, in contrast with those of the forage cultivars. However, they maintained satisfactory mineral content levels and Ca:P and K:(Ca + Mg) ratios (with the exception of E. indica with poor Ca:P ratios and E. crus-galli var. crus-galli with poor P content and Ca:P ratios). All weed species were acceptable to cattle, although there were some differences in palatability among the species.     

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。     

Effects of crop management practices on Echinochloa crus-galli and Chenopodium album seed production in a maize/soyabean rotation

Seed production of residual weed populations needs to be taken into account when estimating the long-term impact of low-input agronomic practices. The objective of this study was to measure the effects and interactions of crop, weed control, tillage practice and nutrient source on the seed production of the dominant residual weed species in a maize/soyabean rotation at two sites: Echinochloa crus-galli (L.) Beauv. on a Sainte-Rosalie clay and Chenopodium album L. on a Duravin clay loam. Seed production per unit area was estimated in each experimental unit. Weed seed production was greater under mechanical weed control compared with chemical weed control. In 1997, E. crus-galli seed production reached over 326 000 seeds m^–2 in mechanical weed control treatments, but averaged less than 500 seeds m^–2 in the chemical weed control treatments. Chenopodium album produced in the range of 766 000 and 73 000 seeds m^–2 in mechanical and chemical weed control treatments respectively. Very few or no weed seeds were produced in soyabean under chemical control. Tillage intensity and nutrient source did not affect seed production of either weed species, with the exception that E. crus-galli produced more seeds in chisel than in mouldboard plough tillage in soyabean. Weed control method had more impact on seed production than tillage intensity and nutrient source in a maize/soyabean rotation.     

Weed-suppressing rice cultivars – does allelopathy play a role?

A range of 111 rice cultivars was studied for weed-suppressing ability in field experiments with a sown infestation of Echinochloa crus-galli. Cultivars differed significantly in their ability to suppress the growth of E. crus-galli , and the differences were reasonably reproducible over three seasons. The same rice cultivars were tested in a laboratory screening for allelopathic potential, which showed significant differences in the ability to reduce root growth of E. crus-galli . Correlation between the laboratory screening and the field experiments showed that field performance could be described to some extent by E. crus-galli root length reduction in the laboratory. Plant height in the field experiment was correlated with weed biomass 8 weeks after seeding. Even among the most weed-suppressing rice cultivars, however, all heights were represented. None of the measured growth parameters from greenhouse studies could explain the distribution of weed-suppressing rice cultivars. This indicates that allelopathy in combination with competitive ability determines the weed interference outcome of a given rice cultivar.     

Effects of salt stress on ion accumulation and antioxidative enzyme activities of Oryza sativa L. and Echinochloa oryzicola Vasing

The effects of salt stress on physiological factors, such as inorganic ion absorption and antioxidative enzyme activities, of rice ( Oryza sativa L. cv. Anapurna) and Echinochloa oryzicola Vasing were investigated. Although having similar morphology, rice and E. oryzicola possessed considerably different salt-tolerance mechanisms. Echinochloa oryzicola was more salt-tolerant than rice. When exposed to salt stress (100 mmol L⁻¹ sodium chloride, NaCl; six days), E. oryzicola had the ability to limit the accumulation of sodium ions (Na⁺), maintained high potassium ion (K⁺) content and had a constantly higher K⁺/Na⁺ ratio than rice. Rice was not effective in limiting Na⁺ absorption but had a higher antioxidative capacity than E. oryzicola . The constitutive activities of superoxide dismutase (SOD) and catalase of rice were three and five times higher than that of E. oryzicola, respectively. Induced activities of SOD, ascorbate peroxidase and glutathione reductase were also higher in rice than in E. oryzicola . The high antioxidative capacity was one of the tolerance mechanisms used by rice to cope with salt stress. Therefore, the salt tolerant-mechanisms are different between the two plants.     

氯氟吡啶酯对稻田杂草的室内除草活性及田间药效评价

氯氟吡啶酯是美国陶氏益农公司最新研制开发的芳基吡啶甲酸酯类除草剂.为了明确其在水稻田的应用技术,采用温室盆栽法测定了氯氟吡啶酯对稻田主要杂草的防效以及对8个水稻品种的安全性,同时开展了田间药效评价试验.温室测定结果表明,氯氟吡啶酯对鸭舌草、鳢肠、耳基水苋、碎米莎草、异型莎草和稗均有较好的除草活性,对千金子的除草活性相对...     

Effect of temperature on herbicidal properties of MTB-951, a mycoherbicide to control Echinochloa crus-galli L.

MTB-951 is a potential mycoherbicide using a fungal plant pathogen ( Drechslera monoceras ) isolated from native Echinochloa species in Japan. Conidia of this pathogen were used as the active ingredient and the effect of temperature on its properties was examined in a laboratory. The optimum temperature for conidium germination was broad between 15 and 35°C and no difference in the germination ratio existed within this temperature range. Mycelial growth was the fastest at 25°C but was slower outside of the range 15–35°C. When leaves of Echinochloa crus-galli L. were immersed in deionized water containing the conidia, cellular electrolyte leakage from the leaves was observed. However, no electrolyte leakage occurred from leaves of rice ( Oryza sativa L.) under the same conditions. The occurrence of electrolyte leakage from E. crus-galli was dependent on the temperature and was the highest at 25°C. Herbicidal activity of MTB-951 against E. crus-galli was high between 25°C and 30°C, but decreased at 35°C in a glass vessel. In the present study, it was revealed that the physiological and herbicidal properties of MTB-951 depended on the temperature.     

持续盐胁迫对制干辣椒生长的影响

以改良佳线、赤峰板椒、日本金塔三个制干辣椒品种为材料,利用不同浓度的Na HCO3从辣椒现蕾期开始进行持续胁迫处理,定期采样测定其生长与生理指标,以确定持续盐胁迫对制干辣椒生长的影响。研究结果表明:30 mmol·L-1、60 mmol·L-1Na HCO3短期胁迫一定程度上可以促进改良佳线和日本金塔的生长;30 mmol·L-1Na HCO3胁迫可促进改良佳线与日本金塔叶绿素合成,60 mmol·L-1Na HCO3胁迫下,日本金塔与改良佳线叶绿素含量没有明显下降;而在低浓度盐胁迫下赤峰板椒的生长和叶绿素合成已经受到抑制,90 mmol·L-1Na HCO3胁迫下,三种辣椒生长和叶绿素合成均受到抑制;三种辣椒的丙二醛含量和质膜透性均随胁迫浓度的加重和时间的延长表现为上升的趋势,说明盐胁迫越重,胁迫时间越长,质膜受损伤的程度越高,改良佳线与日本金塔的上升幅度要小于赤峰板椒;Na HCO3胁迫下,三种辣椒脯氨酸含量均大于对照,并且叶片内脯氨酸的积累随胁迫强度的增加而增加。与赤峰板椒相比,改良佳线与日本金塔有较强的脯氨酸积累能力。综合分析得出,改良佳线与日本金塔耐盐性良好,赤峰板椒耐盐性弱。     

Differences in physiological responses to NaCl between salt-tolerant Sesbania rostrata Brem. & Oberm. and non-tolerant Phaseolus vulgaris L.

Sesbania rostrata ( S. rostrata) Brem. & Oberm., a member of the Fabaceae family, has been used as a promising halophytic plant to ameliorate soil salinity in north-east Thailand. To obtain information regarding the mechanism of salt tolerance, the physiological responses of S. rostrata to NaCl was compared with those of the salt-susceptible species, kidney bean ( Phaseolus vulgaris L. cv. Meal). Seedlings were grown hydroponically with 0, 50, 100 and 150 m m NaCl for 10 days and their effects on growth, chlorophyll content, fluorescence yield ( F _v/ F _m), inorganic elements and amino acid content were determined. The results showed that tolerance to NaCl was clearly different between the two plants. At the highest concentration (150 m m ), the dry weight of S. rostrata was more than 50% greater than the control, whereas the kidney bean could not survive. Chlorophyll a content drastically reduced only in the kidney bean. The F _v/ F _m of S. rostrata did not change with increasing concentrations of NaCl, but that of kidney bean decreased. Greater percentages (≥80%) of absorbed Na⁺ and Cl^– were translocated and accumulated in the shoots of S. rostrata , but remained largely in the roots of kidney bean. The enhancement of contents of amino acids, including proline, with increasing NaCl was observed in both species. These results strongly suggest that the salt tolerance of S. rostrata is associated with the ability of the plant to translocate and sequester Na⁺ and Cl^– in the shoot cells.     

Effects of salt treatment on growth,lipid membrane peroxidation,polyphenol content,and antioxidant activities in leaves of Sesuvium portulacastrum L.

Changes in growth, leaf contents of proline, oxidative stress-related parameters, and phenolic compounds, and antioxidant activities were investigated in the halophyte species Sesuvium portulacastrum L. under saline conditions. Rooted cuttings were individually cultivated in sandy soil. After five weeks of pre-treatment, seedlings were submitted during one month to different salt concentrations ranging from 0 to 800?mM NaCl. The plant growth was significantly improved by salt at 200–600?mM concentration. This trend was associated with (i) the stimulation of photosynthetic activity, (ii) the protection of membrane integrity (leaf MDA content 50% lower than the control), and (iii) higher total antioxidant activity, especially at 400?mM NaCl. At this salt concentration plants accumulated high contents of proline, polyphenols, antocyanins, and carotenoids. These compounds could be implied in the protection of the photosynthetic system and in the improvement of growth. Exposure to 800?mM NaCl impaired significantly photosynthesis, proline, polyphenol, antocyanin, and carotenoid accumulation. Yet, the strong antiradical activity (DPPH) observed at this extreme salinity might partly explain the plant survival. S. portulacastrum could be used in the rehabilitation and the stabilisation of saline or saline arid land. Additionally, under saline conditions, S. portulacastrum accumulate a large amount of proline and exhibits important antioxidant potentialities.     

Herbicidal and fungicidal activities and identification of potential phytotoxins from Bidens pilosa L. var. radiata Scherff

This study was carried out to examine the possibility of utilizing Bidens pilosa , a weed widely distributed in the subtropics and the tropics, for weed and plant fungus control. The extract of B. pilosa shows strong phytotoxic action against the growth of Raphanus sativus and Echinochloa crus-galli and antifungal activity against phytopathogens in bioassays. The extract of the roots exhibited plant growth inhibitory activity more than those of the leaves and stems. Fifteen phenolic compounds, including pyrocatechin, salicylic acid, p -vinylguaiacol, dimethoxyphenol, eugenol, 4-ethyl-1,2-benzenediol, iso- vanillin, 2-hydroxy-6-methylbenzaldehyde, vanillin, vanillic acid, p -hydroxybenzoic acid, protocatechuic acid, p -coumaric acid, ferulic acid, and caffeic acid were identified by gas chromatography–mass spectrometry. Caffeic acid was in the highest amount among the detected substances. Dimethoxyphenol and vanillic acid were found only in the roots of B. pilosa . Ferulic acid and p -hydroxybenzoic acid were higher in the roots than in the leaves and stems. These identified constituents might be responsible for the phytotoxic and fungitoxic activities of B. pilosa.     

四翅滨藜主要渗透调节物质对NaCl胁迫累积的响应

采用盆栽沙培方法,研究四翅滨藜主要渗透调节物质对NaCl浓度和盐胁迫时间的响应。结果表明：① 胁迫时间对四翅滨藜叶片中脯氨酸、Na⁺、K⁺、Cl^-含量和K⁺/Na⁺有极显著影响。随着胁迫时间的延长,叶中脯氨酸、Na⁺含量增加,K⁺含量、K⁺/Na⁺下降,Cl-含量变化趋势较复杂;NaCl胁迫<40 d时,脯氨酸和Na⁺含量增加幅度相对较小,>40 d时均大幅增加。② NaCl浓度对四翅滨藜叶片中脯氨酸、Na⁺、K⁺、Cl^-含量和K⁺/Na⁺也有极显著影响。随着NaCl浓度的增加,叶中脯氨酸、Na⁺含量增加,K⁺含量、K⁺/Na⁺下降;高NaCl浓度处理下,脯氨酸和Na⁺含量增加幅度以及K⁺含量、K⁺/Na⁺下降幅度均较大。③ 四翅滨藜体内离子运输具有选择性。盐胁迫下,根向茎选择运输K⁺,将Na⁺滞留在根部;茎向叶选择运输Na⁺,抑制了K⁺向叶片的运输,使从根部运输的K⁺贮存在茎中;不同营养器官中K⁺/Na⁺从高到低依次为：茎>叶>根,并且都随着NaCl浓度的增加而降低。随着胁迫时间的延长,NaCl浓度对脯氨酸、K⁺、Na⁺及K⁺/Na⁺的影响逐渐放大,并且NaCl浓度与胁迫时间的交互作用也对以上指标（除K⁺外）有极显著影响,因此在研究盐分浓度对植物盐胁迫的影响时,应考虑时间因素及盐分浓度与胁迫时间的交互作用。
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NaCl胁迫对骆驼蓬幼苗叶片多胺水平的影响

研究了NaCl胁迫对骆驼蓬幼苗叶片多胺组分、多胺氧化酶(PAO)活性及H2O2和丙二醛(MDA)含量的影响。结果表明,不同浓度NaCl(0、50、100、200和400 mmol/L)胁迫8 d后骆驼蓬幼苗叶片游离态多胺含量随NaCl浓度增大明显下降,高氯酸不溶性结合态多胺下降较小,高氯酸可溶性结合态多胺无显著变化;不同形态多胺中腐胺(Put)含量随NaCl浓度提高显著降低,游离态和高氯酸可溶性结合态精胺(Spm)和亚精胺(Spd)含量先升后降,200 mmol/L NaCl时出现最大值,400 mmol/L时开始下降,但仍高于对照;高氯酸不溶性结合态Spm含量无显著变化而Spd则降低;游离态和细胞壁结合态PAO活性呈先升后降变化趋势;H2O2和MDA含量不断上升。     

NaCl胁迫对剑麻幼苗根毛生长及其生理代谢的影响

以剑麻幼苗为材料,探讨了不同浓度NaCl模拟盐胁迫对剑麻幼苗根毛生长的影响,及胁迫下叶片膜相对透性、丙二醛(MDA)、游离脯氨酸、可溶性糖含量及过氧化物酶(POD)活性和同工酶的变化。结果表明,0.4%NaCl对剑麻根毛的生长抑制作用较轻,且随着NaCl胁迫浓度提高和时间增加,剑麻幼苗根毛受损伤的程度加强;同时叶片膜相对透性和丙二醛(MDA)含量明显升高。本研究结果还表明,较高的盐胁迫引起了剑麻幼苗脯氨酸含量和POD活性的显著增加,以及POD同工酶图谱的变化,因此,推断剑麻幼苗可能通过提高游离脯氨酸含量和过氧化物酶(POD)活性来抵抗NaCl的胁迫伤害作用,提高其对盐分的适应性。     

稗草生防菌新月弯孢菌Culvularia lunata菌株J15(2)的安全性和致病力

为了确定生防菌新月弯孢菌Culvularia lunata菌株J15(2)的安全性及防除稗草的潜力,研究了该菌株的寄主范围,接种孢子时稗草叶龄、接种后保湿时间、接种浓度对该菌株致病力的影响,土壤带菌对稗草出苗的影响,以及与化学除草剂的相互作用.结果显示,菌株J15(2)只能在稗草上侵染并扩展;接种孢子后保湿24 h,对2叶期稗草抑制率可达55.6%,对1.5叶期稗草抑制率可达100%;保&48h,对2叶期稗草防效提高至91.6%;接种孢子量需达1012孢子/hm2才能较好地抑制稗草生长;土壤带菌亦可抑制稗草生长.该菌与化学除草剂精噁唑禾草灵或二氯喹啉酸混用能显著提高除稗效果,菌株J15(2) 3.3 × 1012孢子//hm2分别与精噁唑禾草灵有效剂量3.83g/hm2二氯喹啉酸有效剂量250.00g/hm2混用,对稗草防效分别为99.5%和88.6%,远高于这两个除草剂单用时的药效.该试验结果表明,菌株J15(2)具有作为微生物除草剂的开发潜力.     

Evaluation of the allelopathic potential of Kava (Piper methysticum L.) for weed control in rice

Kava is a perennial pepper plant from the Oceanic region, which is commonly used as a drink by natives and for pharmacological purposes. Results of this study concluded that Kava has allelopathic potential and suppressed germination and growth of lettuce ( Lactuca sativa L), barnyardgrass ( E. crus-galli Beauv var. formosensis Ohwi.), and duck-tongue weed ( M. vaginalis Presl var. plantaginea Solms-Laub.) Moreover, Kava inhibited emergence of weeds in paddy soils. The inhibition of Kava became stronger as the applied concentration increased. In a greenhouse experiment, Kava had the greatest inhibition on emergence and weed growth in paddy soils when a dose of 1 ton ha⁻¹ of Kava was divided and applied at 3, 16, and 23 days after watering. Inhibition by Kava varied among weed species. Results from this study suggest that Kava might be useful for weed control in rice or reduce dependence on herbicide.     

文冠果耐盐性试验研究

利用不同浓度梯度的NaCl单质盐水灌溉试验,研究盐胁迫对文冠果叶片各项生理指标的影响,进而评价文冠果的耐盐特性。试验结果表明:盐胁迫下,文冠果叶片细胞膜相对透性随胁迫浓度的增大而增大,最大时达56.90%,是对照的2.94倍;MDA(丙二醛)含量也有不同程度的增大,SOD(超氧化物歧化酶)和POD(过氧化物酶)活性较对照基本均有所增加,可溶性糖含量也有一定的积累,在0.4%时达到最大值为0.72g/g·FW,可以缓解由盐溶液引起的渗透胁迫,文冠果在一定范围内有一定耐盐性。     

Effect of δ-aminolevulinic acid on the herbicidal efficacy of foliar-applied MTB-951, a mycoherbicide to control Echinochloa crus-galli L.

The conidia of a plant pathogen ( Drechslera monoceras [Drechsler] Subram. et Jain [=  Exserohilum monoceras [Drechsler] Leonard et Suggs]), MTB-951, which was isolated from native Echinochloa species in Japan, were used as the herbicidal active ingredient. The effects of δ-aminolevulinic acid (ALA) on the efficacy of foliar-applied MTB-951 on Echinochloa crus-galli L. were examined. First, foliar-applied MTB-951 exhibited almost no efficacy when no dew period was provided. However, the efficacy increased depending on the length of the dew period. MTB-951 and ALA exhibited an additive effect on E. crus-galli under 3 day dew conditions, although they exhibited a significant synergistic effect under no-dew conditions. When the leaves of E. crus-galli were immersed in deionized water containing the conidia of MTB-951, cellular electrolyte leakage from the leaves was observed. The ALA increased the electrolyte leakage by MTB-951 synergistically. Also, ALA increased the number of lesions on the leaves of E. crus-galli caused by MTB-951 under light conditions but failed to increase the number under dark conditions. These results suggest that ALA promotes infection with MTB-951 for E. crus-galli through its photodynamic action.     

烟草试管苗对盐胁迫的生理响应

利用不同浓度的NaCl对烟草试管苗进行了20 d胁迫,结果发现:随着盐浓度的增加,烟草试管苗的生长明显受阻;根、茎、叶中K 的含量呈极显著的下降趋势,Na 的含量大幅度增加;叶片中叶绿素的含量下降,但丙二醛的含量增加,质膜透性增大,脯氨酸大量积累,且脯氨酸含量与丙二醛含量和质膜透性间呈极显著的正相关,表明盐胁迫下脯氨酸积累的多少可反映烟草试管苗的伤害程度.本研究认为离子伤害、膜透性增大和叶绿素含量下降是影响盐胁迫下烟草试管苗生长的原因.