水杨酸对小麦高盐毒害的缓解作用

以盐敏感品种中国春、农大８５０２１和抗盐品种冬６８、茶淀红等４个品种小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）为材料,研究盐分胁迫对小麦种子萌发和幼苗生长的影响以及水杨酸对盐害的缓解作用．结果表明,水杨酸能够相对提高盐分胁迫条件下小麦种子萌发的数量、速度和质量;提高幼苗根和叶内游离脯氨酸、可溶性糖等渗透调节物质的含量,增强其渗透调节能力,同时提高幼苗体内超氧化物歧化酶、过氧化物酶等细胞保护酶的活性,抑制膜脂过氧化作用产物丙二醛的积累,降低叶片质膜透性和盐分胁迫对细胞膜的伤害．所有这些变化都有利于缓解盐害,提高小麦抗盐性     

水杨酸对铅胁迫下黄瓜幼苗叶片膜脂过氧化的影响

以黄瓜幼苗为材料,研究了外源水杨酸对铅胁迫下黄瓜幼苗叶片膜脂过氧化的影响。结果表明:水杨酸使铅胁迫的黄瓜幼苗叶片的丙二醛(MDA)含量下降,可溶性蛋白质含量升高,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性降低;在0~1 mmol.L-1范围内的外源SA对铅胁迫的黄瓜幼苗叶片的丙二醛含量下降量和超氧化物歧化酶活性增加量与水杨酸处理浓度呈正相关,与外源水杨酸处理浓度呈正相关,而过氧化物酶活性增加量与外源水杨酸浓度呈负相关。外源水杨酸的作用可能是通过提高黄瓜叶片对膜脂过氧化的抗性来提高黄瓜幼苗对铅毒害的耐受力。     

Impact of osmotic stress on seed germination and seedling growth in black gram (Phaseolus mungo)

An experiment was conducted to see the impact of osmotic stress as it is one of the main cause in various soil and water disorders in agricultural field crops, speciallythe seed germination and seedling growth. The osmotic stress was generated using PEG-6000 and the seed germination, seedling growth were evaluated including the status of pigments i.e. chlorophyll (a, b and total), total carotenoids, pheophytin (a, b and total) and different enzymes like amylase, peroxidase, catalase and superoxide dismutase. The various osmotic potentials generated (-2, -5 and -10 bars) showed significant decrease in germination percentage as at the osmotic potential of -10 bars it was observed 70 in comparison to 90% of control. All the seedling growth parameter also showed inhibition with increase in osmotic potential. Increase in osmotic stress decreased Chlorophyll 'a', while Chlorophyll 'b' was increased in -5 bars while total chlorophyll showed decrease in -5 bars osmotic potential. Total carotenoids and pheophytin (a, b and total) were highly increased in -5 bars and decreased in -10 bars osmotic concentration. Enzymatic activity was found to be decreased in amylase while peroixidase, catalase and SOD were increased at different osmotic gradients in comparison to control. The data observed in the experiment can be helpful to assess the impact of any kind of osmotic stress on plant growth and development in crops.     

Isoperoxidases show differing sensitivity to salicylic acid

The effects of salicylic acid (SA) on the activity of total peroxidase and the patterns of isoperoxidases of cultured tobacco cells were investigated. The total peroxidase activity of tobacco cells was inhibited by 70% when the cells were treated with 5 mM SA for one week. The peroxidase activity of tobacco cells is declined by 90% in the presence of 30 mM SA. Moreover, the activity of isoperoxidases C3, A1, and A3 decreased dramatically with increasing SA concentration, while, one of the anodic isoperoxidases, A2, was somewhat resistant to SA treatment. When isoperoxidase C3 was isolated, SA inhibited the activity of purified C3 in a concentration-dependent manner. The IC50 of isoperoxidase C3 was approximately 0.45 mM. However, the inhibition of isoperoxidase C3 activity was removed by the addition of Fe2+ ion. The possible mechanism of inhibition of peroxidase by SA is discussed.     

Zinc and copper induced changes in physiological characteristics of Vigna mungo (L.)

The effect of deleterious concentration of zinc and copper provided either individually or in combination in the nutrient media was investigated in order to assess the effect of metal interaction in Vigna mungo (L.). Both metals showed negative effect and led to a marked decrease in seed germination (20%), seedling growth (91.7%) and nitrate reductase activity (85.7%) with the increase in metal concentrations. The present study also emphasizes on the response of catalase and peroxidase enzyme under zinc and copper stress. Both antioxidant enzymes exhibited an increasing trend under different treatment conditions but it was reverse at highly toxic metal concentration. The results showed active involvement of peroxidase enzyme in regulating oxidative stress rather than catalase enzyme, as the specific activity of peroxidase enzyme got increased by 8.94% under the combined metals stress whereas catalase activity got declined by 60.97% in comparison to control due to excessive stress. The combined effect of copper and zinc metal was more pronounced in comparison to their individual effects.     

茉莉酸类物质(JAs)的生理特性及其在逆境胁迫中的抗性作用

以茉莉酸(JA)和茉莉酸甲酯(MeJA)为代表的茉莉酸类物质(JAs)是广泛存在于高等植物体内的一种新型植物生长调节物质,在调节植物生长发育、光合特性、抗逆反应等起着重要的作用。茉莉酸类物质能抑制植物生长,抑制种子和花粉粒萌发,促进叶片和果实衰老,加速细胞的分裂和膨大,促进气孔关闭,诱导禾本科植物的颖花开放;此外还能调节植物的光合作用和呼吸作用及保护酶活性。目前更多的研究表明,茉莉酸(酯)类物质是与抗性密切相关的植物生长物质,它作为内源信号分子参与植物在机械伤害、病虫害、干旱、盐胁迫、低温等条件下的抗逆反应。在植物受到伤害时,植物体内茉莉酸及其衍生物的含量显著增加,进而诱导一系列与抗逆有关的基因表达,如蛋白酶抑制剂、硫蛋白和苯丙氨酸转氨酶(PAL)等,提高酯氧合酶活性,从而增强植物的抗性。研究还发现,在干旱逆境胁迫条件下,与脱落酸(ABA)的表现相似,茉莉酸类物质大量积累,外施能增强植物的抗旱性。茉莉酸与脱落酸在抑制生长、促进衰老和逆境胁迫的反应上作用极为相似,两者可协同起作用或独立发挥,而茉莉酸与水杨酸(SA)二者之间则大多研究认为存在相互抑制的拮抗作用,但也有一定协同作用。而茉莉酸与各种激素的信号传导途径的相互作用机制仍有待进一步深入研究。     

UV-B增加与酸雨复合处理对大豆种子萌发和幼苗生长的影响

研究了UV-B辐射增加与酸雨的复合处理对大豆种子萌发和幼苗生长的影响。结果表明：UV-B辐射增加对大豆种子的萌发没有影响，酸雨处理降低了大豆种子的发芽率。UV-B辐射增加与酸雨的复合处理，降低了幼苗的株高、绿叶数、叶面积、干质量、叶绿素和蒸腾速率，复合胁迫的下降幅度明显高于单一因子胁迫，并且下降幅度受UV-B辐射强度与酸雨pH的影响。UV-B辐射增加与酸雨处理在抑制幼苗生长上具有协同作用。     

模拟酸雨对薇甘菊种子萌发和幼苗生长的影响

薇甘菊是入侵性杂草,已在我国华南地区及云南部分地区造成严重危害。我国华南地区同时也是强酸雨分布区域。采用不同pH值的模拟酸雨对薇甘菊种子及幼苗进行处理,测定其对种子萌发和幼苗生长的影响。测定了不同pH值下薇甘菊幼苗叶绿素含量、丙二醛含量、脯氨酸含量、超氧阴离子产生速率、超氧化物歧化酶和过氧化物酶活性。结果表明,薇甘菊种子具有较强的耐酸能力,pH≥3．5时均能正常萌发,pH≤3．0时不能萌发。不同pH值模拟酸雨对薇甘菊幼苗叶绿素含量影响不显著。随着模拟酸雨pH值下降,超氧阴离子产生速率上升,丙二醛含量、脯氨酸含量、超氧化物歧化酶活性和过氧化物酶活性呈先上升后下降。pH3．5时,丙二醛含量、脯氨酸含量、过氧化物酶活性均达最大值;pH4．0时超氧化物歧化酶活性达最大值。结果表明薇甘菊对华南地区酸雨胁迫表现出适应。     

Interference of three weed extracts on uptake of nutrient in three different varieties of paddy through radio tracer techniques

Interference of three dominant weed extracts viz., Ageratum conyzoides L., Melilotus indica All. and Parthenium hysterophorus L. were examined on seed germination, seedling growth, and nutrient uptake (32P and 65Zn) in three different varieties (PD-10, PD-12 and PB) of paddy (Oryza sativa L.). Among the three different varieties irrespective of weed extracts, PD-10 and PD-12 were resistant and PB was susceptible in terms of seed germination, radicle length and plumule dry weight; and PD-12 and PB were resistant and susceptible, respectively, in terms of plumule length and total seedling dry weight. A. conyzoides caused maximum reduction in seed germination and M. indica in seedling growth in different varieties of paddy. The weed extracts interfered in uptake of both 32P and 65Zn and there was a gradual decrease in uptake of both nutrients with increasing concentration of extracts in both root and shoot. The uptake of 32P and 65Zn was more inhibitory with the extracts of A. conyzoides and M. indica, respectively in different varieties. The inhibition in seed germination, seedling growth and nutrient uptake may be due to the presence of phenolics and other secondary metabolities. The phenolics such as gallic, vanillic, protocatechuic and p-hydroxybenzoic acids were identified from these weed extracts.     

紫外辐射对灯盏花附生、内生细菌数量的影响及机理

采用大田研究方法,模拟5.0kJ·m~(-2)紫外辐射(UV-B,280～315nm)增强对灯盏花Erigeronbreviscapus附生、内生细菌数量、优势种群以及类黄酮、游离氨基酸、可溶性蛋白、淀粉和可溶性糖含量的影响.UV-B辐射极显著减少灯盏花苗期叶和花期根与叶附生细菌数量(p<0.01),显著减少灯盏花果熟期根与叶附生细菌数量(p<0.05).极显著减少灯盏花苗期根与叶和花期叶与茎及果熟期茎内生细菌的数量,果熟期根内生细菌数量显著增加.灯盏花附生细菌优势种群为芽孢杆菌Bacillus和欧文氏菌Erwinia,内生细菌优势种群为芽孢杆菌;UV-B辐射可导致灯盏花附生和内生细菌优势种群数目减少.UV-B辐射还会使灯盏花生理指标发生变化,直接导致灯盏花附生细菌数量的减少,可溶性糖、游离氨基酸和可溶性蛋白含量与附生细菌数量呈显著正相关(p<0.05).UV-B辐射增加灯盏花各部位类黄酮含量,间接影响灯盏花内生细菌数量,根类黄酮含量与内生细菌数量呈极显著正相关(p<0.01).     

Stress response to nanoplastics with different charges in Brassica napus L. during seed germination and seedling growth stages

● Higher concentrations of PS, PS-NH₂ and PS-SO₃H inhibited seed germination. ● PS, PS-NH₂ and PS-SO₃H influenced seedling growth in a dose-dependent manner. ● PS, PS-NH₂ and PS-SO₃H reduced essential nutrients uptake and plant quality. ● PS, PS-NH₂ and PS-SO₃H increased antioxidant enzyme activities and MDA content. ● Nanoplastic toxicity was related to surface charges. Nanoplastic pollution has become a significant problem in farmland systems worldwide. However, research on the effects of nanoplastics (NPs) with different charges on field crops is still limited. In our study, NPs with different charges, including unmodified polystyrene nanoplastics (PS), positively charged polystyrene nanoplastics (PS-NH₂), and negatively charged polystyrene nanoplastics (PS-SO₃H), were investigated for their impacts on seed germination and seedling growth of rape. The results showed that seed water uptake (after 12 h), seed germination, seed vigour, and relative root elongation were all significantly reduced under exposure to NPs (200 mg/L). Similarly, remarkable decreases in plant biomass (root weight, shoot weight), growth (root length, plant height), photosynthesis ability (chlorophyll a, chlorophyll b, carotenoids), essential nutrient uptake (Fe, Mn, Zn, Cu), and plant quality (soluble protein, soluble sugar, crude fibre content) of rape seedlings were also observed after exposure to NPs. Among the three kinds of NPs, PS-NH₂ showed stronger effects. Moreover, superoxide dismutase, peroxidase, and catalase activities of rape seedlings were changed, and the content of malondialdehyde was significantly increased under exposure to NPs. Furthermore, positively charged PS-NH₂ showed stronger effects on the phenotype, physiology, biochemistry, nutrient uptake, and plant quality of rape. Notably, a comprehensive toxicity evaluation revealed that PS-NH₂ had the strongest toxicity to rape. The present study provides important implications for the interaction and risk assessment of NPs and crops in soil-plant systems.     

生物炭对小麦种子萌发与幼苗生长的植物毒理效应

为明确生物炭对植物的毒性效应,以石英砂+生物炭水浸提液培养方法研究不同剂量生物炭对小麦种子萌发与幼苗生长的影响。结果表明:在不同剂量(0.0、10.0、20.0、40.0、80.0、160.0 g·kg~(-1))生物炭水浸提液处理下,虽然小麦发芽率较对照组无显著性变化(P0.05),但根、芽生长表现出低剂量促进高剂量抑制,且在160.0 g·kg~(-1)时抑制率最大,分别为18.11%和22.22%。在幼苗的生长期(11 d),高剂量生物炭对幼苗根生长的抑制作用增强,160.0 g·kg~(-1)处理下抑制率显著增加至55.59%(P0.05)。此外,当生物炭剂量较低时,小麦幼苗根、叶中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活力增加;随生物炭剂量的增加,3种抗氧化酶活力降低,丙二醛(MDA)含量升高,幼苗生长出现生理损伤,表现出明显植物毒性效应。     

多金属硫化物矿区不同品种水稻根际土壤酶活的变化

选取酸性矿山废水污灌形成的多重金属污染水稻土,采用多格层根际箱模拟水稻根际环境,研究高镉积累水稻长香谷fOryzasativaL．cv．Choukoukoku）和低镉积累水稻金农丝苗（OryzasativaL．cv．Jinnongsimiao）2个品种水稻生育中后期（分蘖期、孕穗期、扬花期、蜡熟期）根际土壤脲酶、酸性磷酸酶和过氧化氢酶活性的变化特征。结果表明：高镉积累水稻比低镉积累水稻各时期根际土壤脲酶活性低,随着生育期的延长,2个品种水稻土壤脲酶活性先降低后升高（分蘖期酶活性最高）,2种水稻土壤脲酶活性均在根际s0层达到最高,但其他各层土壤脲酶活性与根系距离无显著关系。随着水稻生育期的延长,高镉积累水稻根际土壤酸性磷酸酶活性先升高（在孕穗期酶活性达最高）,随后降低;低镉积累水稻土壤酸性磷酸酶活性则在分蘖期最高,之后逐渐降低。除分蘖期高镉积累水稻土壤酸性磷酸酶活性低于低镉积累水稻酶活性外,其他2个时期前者酸性磷酸酶酶活性均高于后者的酶活。2个品种水稻土壤过氧化氢酶活性随生育期延长不断升高,在整个生育后期,高镉吸收水稻比低镉吸收水稻各时期土壤过氧化氢酶活性高,但在蜡熟期时两者无显著差异;在各时期2种水稻过氧化氢酶活性在根系S0层达到最大,随着与水稻根系距离的增加呈先降低后增加的趋势。可见,在多重金属污染矿区,土壤酶活性明显受水稻品种、水稻生长时期和水稻根系的影响。该结果可以为研究多重金属污染矿区分析土壤酶活性与不同重金属积累程度的水稻品种作物相关关系提供数据支持,给农业生产及土壤修复提供依据。     

聚丁二酸丁二醇酯（PBS）生物降解过程对植物生长的影响评价

通过苏丹草（Sorghum sudanense Stapf）、籽粒笕（Amaranthus hypochondriacus L.）、豇豆（Vigna sesquipedalis Wight）种子的发芽试验及其盆栽试验,考察了PBS在土壤浸提液中的生物降解性能,探讨了PBS高聚物、低聚物和合成单体对植物的发芽和生长影响。研究结果表明：①在土壤浸提液中微生物对PBS有一定的降解作用,且在降解过程中,降解液的pH变化不明显;②PBS高聚物的降解产物对植物生长没有影响;③P BS低聚物在降解初期抑制部分植物的幼苗生长,后期对植物的生长没有影响;④当丁二酸的质量浓度低于200 mg.L^-1时,对植物种子的发芽和幼苗生长不会产生影响,当质量浓度高于500 mg.L^-1时,将抑制幼苗生长;当1,4-丁二醇的质量浓度低于2 000 mg.L-1时,对种子的发芽和生长没有影响。     

模拟酸雨对外来入侵植物三叶鬼针草生长及化感作用的影响

外来入侵植物三叶鬼针草（Bidens pilosa L.）对我国华南地区生态系统造成严重危害,同时华南地区也是强酸雨分布区域。采用不同pH值（2.5,4.0,5.6）的模拟酸雨对三叶鬼针草种子和幼苗进行处理,测定其对种子萌发和幼苗生长的影响;室外模拟酸雨喷淋三叶鬼针草,生物测定三叶鬼针草叶片水浸提液对受体植物的化感作用的变化。结果表明：pH为4.0和5.6的酸雨处理后提高了三叶鬼针草种子的萌发率;pH为4.0的酸雨促进幼苗生长,增加幼苗苗高和生物量;而pH为2.5的酸雨抑制三叶鬼针草种子萌发率和幼苗生长。同时,pH 4.0和2.5酸雨增强了三叶鬼针草叶片水浸提液对受体植物的化感作用。研究表明：三叶鬼针草具有较强的耐酸能力,酸雨胁迫可能通过促进外来入侵植物三叶鬼针草的生长和提高化感潜力而有利于其进一步入侵。     

大气高CO2浓度对油菜氮素同化累积与植株生长的影响

为了指导高CO2浓度条件下甘蓝型油菜Brassica napus L.合理施氮、创建油菜高产高效以及进一步探明油菜氮代谢的调节机制提供理论依据,本研究采用微区试验,研究2个油菜品种（沪油15-33号和742-2）在2个CO2浓度水平（自然CO2摩尔分数400μmol·mol-1和高CO2摩尔分数（800±20）μmol·mol-1）和2个氮素水平（施氮与不施氮）条件下,氮素同化酶（NR和GS）活性和可溶性蛋白含量的变化,以及油菜地上部干物质量和氮素累积量的响应。试验结果表明,高CO2浓度会提高NR和GS活性;在氮素处理的影响方面,NR活性的变化与油菜的品种和生育时期不同有关：在高CO2浓度条件下,品种A在各时期的施氮处理的酶活性高于不施氮处理;品种B只在抽薹期的施氮处理低于不施氮处理,其他时期则升高;对于GS酶活性,在自然CO2浓度条件下施氮会提高GS酶活性,高CO2浓度条件下施氮则降低其活性（苗期除外）。CO2浓度升高会降低叶片中可溶性蛋白含量（盛花期除外）;在正常CO2浓度下,增施氮肥会提高叶片中可溶性蛋白含量,而在高CO2浓度下,增施氮肥会降低叶片中可溶性蛋白含量。CO2浓度升高和增施氮肥都会提高油菜地上部干物质量与氮素累积量,油菜干物质量与氮素累积量总体上与上述测定指标呈极显著相关。     

Impact of fertilizer factory effluent on seed germination, seedling growth and chlorophyll content of gram (Cicer aeritenum)

In the present study effect of fertilizer factory effluent on seed germination, seedling growth and chlorophyll content of gram (Cicer aeritenum) has been carried out, at different concentration of the effluent and time intervals. The effluent is alkaline in nature with strong ammonia odour. The germination percentage of seed, seedling growth and chlorophyll content showed a gradual decline with increase in effluent concentration. At 25% concentration of the effluent, growth promotion in terms of root, shoot length and increase in chlorophyll content recorded at 21 days. However, at higher concentrations of the effluent toxic effects were observed at 21 days. The study suggests that the effluent can be used safely for Cicer aeritenum cultivation, only after proper treatment and dilution.     

Leaf biochemistry of Lycopersicon esculentum Mill. at different stages of plant development as affected by mercury treatment

The effect of mercury (Hg) on the biochemical parameters of Lycopersicon esculentum Mill leaf was studied. Application of mercuric chloride in varying concentrations (0.5, 1.0, 1.5 and 2.0 mM HgCl2 kg(-1) sand) caused significant reduction that went up to 89% and 72% chlorophyll a and chlorophyll b contents respectively (at flowering stage), 69% in carotenoid content, 64% in total soluble protein content and 91% in nitrate reductase activity (all at post-flowering stage). The amounts of nitrate and proline increased maximally (151% and 143% respectively) at the flowering stage, whereas total soluble sugar enhanced by 57% at the post-flowering stage. Changes observed in most of the parameters, were concentration dependent. Such studies seem to be able to discover suitable bioindicators of heavy metal pollution.     

Linking fruit traits to variation in predispersal vertebrate seed predation, insect seed predation, and pathogen attack

The importance of vertebrates, invertebrates, and pathogens for plant communities has long been recognized, but their absolute and relative importance in early recruitment of multiple coexisting tropical plant species has not been quantified. Further, little is known about the relationship of fruit traits to seed mortality due to natural enemies in tropical plants. To investigate the influences of vertebrates, invertebrates, and pathogens on reproduction of seven canopy plant species varying in fruit traits, we quantified reductions in fruit development and seed germination due to vertebrates, invertebrates, and fungal pathogens through experimental removal of these enemies using canopy exclosures, insecticide, and fungicide, respectively. We also measured morphological fruit traits hypothesized to mediate interactions of plants with natural enemies of seeds. Vertebrates, invertebrates, and fungi differentially affected predispersal seed mortality depending on the plant species. Fruit morphology explained some variation among species; species with larger fruit and less physical protection surrounding seeds exhibited greater negative effects of fungi on fruit development and germination and experienced reduced seed survival integrated over fruit development and germination in response to vertebrates. Within species, variation in seed size also contributed to variation in natural enemy effects on seed viability. Further, seedling growth was higher for seeds that developed in vertebrate exclosures for Anacardium excelsum and under the fungicide treatment for Castilla elastica, suggesting that predispersal effects of natural enemies may carry through to the seedling stage. This is the first experimental test of the relative effects of vertebrates, invertebrates, and pathogens on seed survival in the canopy. This study motivates further investigation to determine the generality of our results for plant communities. If there is strong variation in natural enemy attack among species related to differences in fruit morphology, then quantification of fruit traits will aid in predicting the outcomes of interactions between plants and their natural enemies. This is particularly important in tropical forests, where high species diversity makes it logistically impossible to study every plant life history stage of every species.     

Effect of rubber factory effluent on seed germination and seedling growth of Vigna radiatus L

Physico-chemical analysis of the rubber factory effluents revealed high amounts of total suspended and dissolved solids. Sulphate, phosphate, total nitrogen were also present in significant amounts. At higher concentration (above 50%) of effluent, the seed germination percentage was retarded. Diluted effluent (upto 50%) favoured seedling growth. Length of root system, shoot system and number of lateral roots were increased by low concentrations of effluent.