裸果木渗透调节物质和抗氧化酶活性对干旱的响应

裸果木(Gymnocarpos przewalskii)起源于古地中海,为荒漠区少有的第三纪孑遗植物种。本文采用2017年6月、7月和8月采集于甘肃安西自然保护区内的裸果木中龄和老龄植株叶片,分析自然干旱影响下叶片渗透调节物质及抗氧化酶活性的变化。结果表明:随着干旱程度的增加,裸果木叶片的可溶性蛋白(SP)显著积累,发挥着重要的渗透调节作用,中龄植株叶片的可溶性糖(SS)含量和老龄植株叶片的脯氨酸(Pro)含量先增加后显著降低,渗透调节作用有限。干旱加剧时,中龄植株叶片的超氧化物歧化酶(SOD)活性和抗坏血酸过氧化物酶(APX)活性呈明显的先增后降。严重干旱时,过氧化物酶(POD)活性和过氧化氢酶(CAT)活性明显增强,说明其通过4种酶的协同作用清除过剩的活性氧,减轻过氧化伤害;老龄植株叶片的CAT活性持续增强,APX活性明显的先升后降,POD活性在重度干旱时显著增强,主要通过这3种酶减轻膜系统伤害。丙二醛(MDA)含量则随干旱程度增大显著增加,膜脂过氧化程度不断加深。在相同的降雨条件下,裸果木中、老龄植株的Pro、SS、SP含量、POD和CAT活性、MDA含量对干旱的响应程度存在显著差异,隶属度函数评价法表明,老龄植株的抗旱能力大于中龄植株,表明裸果木的抗旱性随年龄的增大而提高。     

有机肥对酿酒葡萄土壤微生物、酶活性及产量的影响

为明确施用不同有机肥对土壤有机质、酶活性和微生物以及酿酒葡萄产量的影响,采用田间小区设计,以5 a生赤霞珠酿酒葡萄为试验材料,研究不同有机肥对土层0～20、20～40 cm和40～60 cm中土壤有机质、酶活性和微生物的影响。以不施用有机肥为对照(CK),设置沼渣(BR)、羊粪有机肥(SMOF)、牛粪有机肥(CMOF)、猪粪有机肥(PMOF)、牛粪+沼渣有机肥(CMOF+BR)5个处理进行大田试验。结果表明:不同有机肥施用后与CK相比,土壤有机质增加6.79%～44.97%,土壤微生物碳增加19.78%～91.53%,微生物氮增加2.22倍～3.93倍,碱性磷酸酶增加57.78%～512.55%,过氧化氢酶增加53.45%～240.48%,增产15.12%～46.89%。不同土层施用牛粪有机肥相对于其它有机肥处理土壤有机质含量增长8.49%～33.29%;土壤中微生物碳、氮的含量分别增加5.30%～42.46%和6.12%～49.65%;碱性磷酸酶增大8.01%～184.63%,过氧化氢酶增加5.14%～84.27%,脲酶提高25.58%～410.70%,蔗糖酶升高6.00%～107.65%;微生物总数增多5.99%～56.56%。施用牛粪有机肥相比较其它有机肥增产7.08%～27.60%。说明在宁夏地区施用有机肥可有效提高土壤有机质的含量,增加微生物的数量,增加土壤酶活性,促进酿酒葡萄的生长发育,提高产量,其中以牛粪效果最为显著。     

Effect of transferring lignocellulose-degrading bacteria from termite to rumen fluid of sheep on in vitro gas production,fermentation parameters,microbial populations and enzyme activity

The digestive tract of termite(Microcerotermes diversus) contains a variety of lignocellulose-degrading bacteria with exocellulases enzyme activity, not found in the rumen, which could potentially improve fiber degradation in the rumen. The objectives of the current study were to determine the effect of inoculation of rumen fluid(RF) with three species of bacteria isolated from termite digestive tract, Bacillus licheniformis, Ochrobactrum intermedium, and Microbacterium paludicola, on in vitro gas production(IVGP), fermentation parameters, nutrient disappearance, microbial populations, and hydrolytic enzyme activities with fibrous wheat straw(WS) and date leaf(DL) as incubation substrate. Inoculation of RF with either of three termite bacteria increased(P0.05) ammonia-N concentration compared with the control group(free of termite gut bacteria). Termite bacteria inoculation had no effect(P0.05) on gas production characteristics, dry matter, organic matter and neutral detergent fiber disappearance, pH, and concentration and composition of volatile fatty acids. Population of proteolytic bacteria and protozoa, but not cellulolytic bacteria, were increased(P0.05) when RF was inoculated with termite bacteria with both WS and DL substrates. Inoculation of RF with termite bacteria increased protease activity, while activities of carboxymethyl-cellulase, microcrystalline-cellulase, α-amylase and filter paper degrading activity remained unchanged(P0.05). Overall, the results of this study indicated that transferring lignocellulose-degrading bacteria, isolated from digestive tract of termite, to rumen liquid increased protozoa and proteolytic bacteria population and consequently increased protease activity and ammonia-N concentration in vitro, however, no effect on fermentation and fiber degradation parameters were detected. These results suggest that the termite bacteria might be rapidly lysed by the rumen microbes before beneficial effects on the rumen fermentation process could occur.     

Effects of post-silking water deficit on the leaf photosynthesis and senescence of waxy maize

Waxy maize is widely cultivated under rainfed conditions and frequently suffers water shortage during the late growth stage. In this study, a pot trial was conducted to examine the effects of post-silking drought on leaf photosynthesis and senescence and its influence on grain yield. Two waxy maize hybrids, Suyunuo 5(SYN5) and Yunuo 7(YN7), were grown under the control and drought(soil moisture content was 70–80% and 50–60%, respectively) conditions after silking in 2016 and 2017. The decrease in yield was 11.1 and 15.4% for YN7 and SYN5, respectively, owing to the decreased grain weight and number. Post-silking dry matter accumulation was reduced by 27.2% in YN7 and 26.3% in SYN5. The contribution rate of pre-silking photoassimilates transferred to grain yield was increased by 15.6% in YN7 and 10.2% in SYN5, respectively. Post-silking drought increased the malondialdehyde content, but decreased the contents of water, soluble protein, chlorophyll, and carotenoid in the leaves. The weakened activities of enzymes involved in photosynthesis(ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxylase) and antioxidant system(catalase, superoxide dismutase and peroxidase) reduced the photosynthetic rate(P_n) and accelerated leaf senescence. The correlation results indicated that reduced Pn and catalase activity and increased malondialdehyde content under drought conditions induced the decrease of post-silking photoassimilates deposition, ultimately resulted in the grain yield loss.     

油菜素内酯浸根对水稻水卷苗机插植伤的修复效应

目的 探究油菜素内酯(Brassinolide, BR)浸根对机插水卷苗栽后本田生长及产量的影响。方法 以宁粳8号为试验材料,分析不同浓度BR(T1、T10、T20,分别表示水培营养液中BR浓度为1 mg/L、10 mg/L、20 mg/L)浸根对水卷苗机插本田后返青活棵及产量的影响,以正常水培营养液处理为对照(CK)。结果 BR浸根(T1、T10、T20)能够促进水稻地上部生长,栽插本田21d后株高较CK分别增加11.68%、8.12%和7.61%;BR浸根对水卷苗栽后根系的促生作用更为明显,不同浓度BR浸根对水卷苗栽后根长、根表面积、根尖数、根体积、根直径、根质量和根冠比均产生了显著影响,其中根尖数以低浓度BR处理效果更优,而其他根系指标均以高浓度BR处理效果更优。与CK相比,不同浓度BR浸根降低了叶片过氧化氢浓度(至移栽后12 d,分别降低12.50%、23.25%和22.25%),增强了叶片抗氧化酶活性;与移栽当天相比,移栽后第2天BR浸根处理叶片中玉米素(ZT)浓度迅速增加(分别为197.27%、153.11%和243.78%),而CK增加缓慢(2.94%),根系表现一致,且根系中生长素(IAA)浓度显著高于CK;同时BR处理在栽后一周内赤霉素(GA₃)浓度均明显高于对照。与CK相比,T10处理显著提高了每穗粒数和结实率(分别为15.04%和6.62%),T20处理显著提高了结实率(6.17%),但BR处理千粒重均显著下降,最终产量T10和T20处理较CK分别提高5.11%和7.99%。结论 适当浓度的BR(T10~T20)浸根能减轻水卷苗机插植伤,提高抗氧化酶活性,降低H₂O₂含量,提高ZT、GA₃和IAA浓度,高效地促进根系生长,提高了每穗粒数和结实率。本研究可为减轻机插植伤,促进机插水稻高产稳产提供理论依据和技术参考。     

不同生育时期低温胁迫对水稻保护酶的影响

通过吉林省内外优质水稻品种为材料，分别在苗期、分蘖期、减数分裂期、灌浆成熟期进行低 温胁迫处理，并进行其生理特性研究。结果表明，低温胁迫下水稻的CAT、POD、SOD 酶活性均有所 增高，其中部分品种的SOD 酶活性整体较强，在各个时期均有所增幅，而CAT 和POD 酶活性在不同 时期存在品种差异，且分蘖期大部分品种的三种保护酶均有明显提升。本试验材料中，不同时期低温 胁迫下，通系935、龙稻18、吉粳816、绥粳14、延粳22、通35 的整体酶活性在各个时期表现优异，优于 其余品种。     

外源铬对延胡索生理指标及抗氧化系统变化的影响

为探究不同浓度外源Cr6+处理下，延胡索（Corydalis yanhusuo）生理指标及抗氧化系统的变化情况，测定了延胡索植株内铬含量、株高、生物量以及抗氧化系统各项指标。结果表明：当土壤中Cr6+浓度在67.32~323.32 mg·kg-1范围内，随着土壤中Cr6+浓度的升高，延胡索体内Cr6+累积量增加。延胡索植株株高、生物量表现为先升后降趋势，当土壤中Cr6+浓度低于131.32 mg·kg-1时，延胡索生长受到促进，而且这种作用具有一定的浓度依赖性：当土壤中Cr6+浓度低于131.32 mg·kg-1时，超氧化物歧化酶（superoxide dismutase, SOD）有较高活性,将超氧阴离子自由基歧化分解为H2O2，此时过氧化物酶（peroxidase, POD）、过氧化氢酶（catalase, CAT）活性均呈上升趋势，将H2O2分解，延胡索植株的生长受到促进作用；当土壤中Cr6+浓度达到195.32 mg·kg-1后，延胡索受到的胁迫严重，SOD活性有较大幅度的下降，植株体内超氧阴离子自由基大量累积，延胡索植株生长受到抑制。     

Dietary Photoprotective Compounds Ameliorate UV Tolerance in Shrimp (Pleoticus muelleri) through Induction of Antioxidant Activity

The aim of this study was to determine the effects of ultraviolet radiation (UVR) on bioaccumulation of UV‐absorbing compounds acquired through the diet, in larvae and postlarvae of Pleoticus muelleri, and to assess tissue antioxidant activity, survival, and development. Mysis stage I were exposed to two artificial radiation treatments: M‐PAR (photosynthetically active radiation, range = 400–700 nm) and M‐PAR + UVR (280–700 nm). The experimental larvae received a mixed dietary treatment of Artemia persimilis and the microalga Pavlova lutheri, reared under two radiation regimes: PAR (D‐PAR) and PAR + UVR (D‐PAR + UVR). Shrimp from all treatments reached 8 d postlarval stage (PL8), except those under M‐PAR + UVR treatment fed the D‐PAR‐cultured algae, which had 0% survival. Larvae in M‐PAR + UVR and M‐PAR treatments fed with D‐PAR + UVR diet presented the highest survival rates (70 and 75%, respectively), with 37 and 41% increase in PL size. UV‐absorbing compounds were detected in microalgae and PL subject to PAR + UVR treatments. Antioxidant activity, quantified by measuring the free‐radical 1,1‐diphenyl‐2‐picrylhydrazyl in homogenates of PL8, decayed drastically under radiation treatment M‐PAR + UVR fed with algae of the D‐PAR + UVR treatment. It is concluded that the bioaccumulation of UV‐absorbing compounds and the highest antioxidant activity in PL could improve the biochemical and photophysiological responses of shrimp under UVR stress.     

昆虫嗅觉相关蛋白的研究进展

昆虫对自然环境中复杂化学信号的识别多依赖于其灵敏的嗅觉系统,选择寄主、觅食、寻找配偶等行为的发生都以嗅觉识别为基础,而完成嗅觉识别还需要多种嗅觉相关蛋白的参与。嗅觉相关蛋白主要包括6种,即气味结合蛋白、化学感受蛋白、气味受体、感觉神经元膜蛋白、离子型受体和气味降解酶。不同种类和性别的昆虫中,嗅觉蛋白的种类、数量和分布各不相同。由于嗅觉蛋白在昆虫识别外界气味分子中的重要作用,国内外近年来对其展开了广泛、深入的研究。本文从几种嗅觉相关蛋白的生化特性、分子结构、生理功能、分布表达部位和研究概况等角度,较详细地综述了近年来国内外昆虫嗅觉相关蛋白的研究进展。     

Sorghum extrusion process combined with biofortified sweet potato contributed for high iron bioavailability in Wistar rats

This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n = 7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES + SP group showed higher (p < 0.05) expression of DcytB, ferroportin and hephaestin when compared to the control group. The DS group showed high (p < 0.05) expression of DMT-1 and the ES showed high mRNA expression of transferrin and ferritin. The changes in the sorghum physicochemical properties from extrusion process reduced the iron and phytate content, and increased the gene expression of proteins involved in iron metabolism, improving iron bioavailability. The combination of sweet potato and sorghum flour (dry or extruded) improved the iron capture and total antioxidant capacity, probably due to the presence of β-carotene and antioxidant compounds.