Pseudomonas putida improved soil enzyme activity and growth of kasumbha under low input of mineral fertilizers

Effective management of the nutrients and enzyme activity in the soil is necessary for maximum crop growth and productivity. However, the excessive use of chemical fertilizers (CFs) not only adversely affects the soil nutrient status and soil physicochemical properties but also aids pollution to the ecosystem. The objective of present study was to investigate the effect of single as well as combined applications of phosphate-solubilizing bacteria and agrochemicals on important soil enzyme activities and their impact on the growth of kasumbha (safflower). Pseudomonas putida (P. putida;10⁶ cells/mL) was applied as seed inoculation prior to sowing, and CFs were applied as full, half, and quarter doses during sowing to modulate the growth of kasumbha host plants. P. putida in combination with half dose of CFs (PH) increased the soil urease and phosphatase activities, while P. putida combined with quarter dose of CFs (PQ) augmented the soil invertase activities. Moreover, the PQ treatment exhibited the maximum colony-forming units of P. putida. Leaf chlorophyll, carotenoids, protein contents, and root lengths were increased by PH treatment. Whereas, shoot length and leaf area were improved by PH and PQ treatments, respectively. Leaf protease activity was enhanced by P. putida in combination with full dose of CFs and PQ treatments, while leaf phosphate contents were significantly improved by PQ treatment. It can be concluded that P. putida in combination with half as well as quarter doses of CFs is a promising approach for the improvement of soil enzyme activities and growth of kasumbha and replacing 50% of the use of CFs.     

Nutrient release pattern of organic and inorganic resources used in cassava production (Manihot esculenta Crantz)

The major constraint in the promotion of organic farming, a safe and sustainable alternative, is lack of availability of quality organic resources in sufficient quantities. The quality of resources can be ascertained by monitoring its nutrient release pattern, which has not yet been attempted. A controlled condition pot experiment was conducted at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, India, in completely randomized design to study the nutrient dynamics of various organic and inorganic resources, commonly used in cassava production, at monthly intervals up to six months. The release of almost all nutrients and activity of soil enzymes were higher at the middle (3 or 4?months) of the incubation period. The pH showed an increasing trend and electrical conductivity, organic C and Fe content declined from initial. Averaging over stages, organic practice favored the activity of soil enzymes and release of almost all nutrients over conventional system significantly, except N.     

海拔对藜麦苗期生理指标的影响

选择甘肃省不同海拔地区,以国内首个藜麦品种陇藜1号为材料,测定不同海拔对藜麦苗期叶片生理指标的影响。结果表明,随海拔的升高,藜麦叶片的叶绿素、可溶性蛋白和脯氨酸含量先升高后下降;MDA含量和O_2~-产生速率升高后下降再升高,在海拔最高(2 130 m)处达到最大值;SOD、POD、CAT和APX活性先升高后下降。说明随海拔的升高,藜麦叶片通过积累渗透调节物质和提高抗氧化酶活性,以清除多余的活性氧物质,维持细胞渗透势平衡,缓解环境变化对其生长造成的伤害。     

Microbial Degradation of Organophosphate Pesticides: A Review

Pesticides have become an inevitable part of the modern environment as they are widely used in agriculture,household,and public health sectors and,hence,are extensively distributed throughout most ecosystems.Currently,organophosphate pesticides are the most commercially favored group of pesticides,with large application areas all over the world.Depending on their fate,these organophosphorus compounds may become bioavailable for microbial degradation.Environmental microbes,such as Aspergillus,Pseudomonas,Chlorella,and Arthrobacter,are capable of coupling a variety of physical and biochemical mechanisms for the degradation of organophosphate pesticides,including adsorption,hydrolysis of P–O alkyl and aryl bonds,photodegradation,and enzymatic mineralization.Enzymes,such as esterase,diisopropyl fluorophosphatase,phosphotriesterase,somanase,parathion hydrolase,and paraoxonase,have been isolated from microbes to study and understand the catabolic pathways involved in the biotransformation of these xenobiotic compounds.This review highlights various aspects of biodegradation of organophosphate pesticides along with biological and molecular characterization of some organophosphate pesticide-degrading bacteria.     

LED补光对水稻秧苗素质及其生理特征和产量的影响

采用发光二极管(light-emitting diode,LED)精确调制光谱能量,研究不同光质对水稻秧苗素质(株高、根长和鲜干重)和生理特征(内源激素、抗氧化酶、可溶性蛋白和丙二醛)的影响,探讨生理特征与秧苗素质和补光移栽后产量的耦合关系。水稻秧苗分别在5种光质下进行补光照射:R (100%红光),B (100%蓝光),RB (80%红光+20%蓝光)RBG_12.5(62.5%红光+25%蓝光+12.5%绿光),RBG₂₅(50%红光+25%蓝光+25%绿光),光量子通量均为1 000μmol·m^-2·s^-1,照射30 d (6 h/d)后采样,并插秧至稻田,以无补光作为对照(CK)。与CK相比,LED补充光源显著(P<0.05)影响水稻秧苗的株高、根长和鲜干重。株高和地上部分干重最大值分别出现在R和RBG_12.5处理,而根长和地下部分干重的最大值均出现在RBG_12.5处理。LED补充光源对内源激素、抗氧化酶、可溶性蛋白和丙二醛的影响程度因光质和植物部位而异。与CK相比,RBG_12.5二显著(P<0.05)提高地上部生长素(IAA)含量和可溶性蛋白含量,B显著(P<0.05)提高地上部超氧化歧化酶(SOD)活性、过氧化物酶(POD)活性和丙二醛(MDA)含量;RBG_12.5和RBG₂₅显著(P<0.05)提高地下部IAA含量,RBC₂₅显著(P<0.05)提高地下部可溶性蛋白含量和MDA含量。补光移栽后水稻产量的变化趋势与光质对水稻秧苗壮苗指数的影响趋势一致:RBG_12.5> RBG25> RB> B> R> CK。逐步回归分析发现,壮苗指数与地上部赤霉素(GA_3)含量和IAA含量及地下部IAA含量和SOD活性显著正相关;补光移栽后产量与秧苗地上部IAA含量及地下部IAA含量和过氧化氢酶(CAT)活性显著正相关。LED补充光源通过调节水稻秧苗生理特征影响其素质,且影响效应延续至水稻成熟期。RBG_12.5光源更利于培育水稻壮苗和水稻增产,适宜用作工厂化育秧的补充光源。     

紫斑牡丹种子浸提液对植物种子萌发和幼苗生长的影响

以紫斑牡丹种子为研究对象,研究不同质量浓度(0、0.025、0.050、0.075、0.100 g·mL-1)的种皮和胚乳水浸提液对白菜、小麦和绿豆种子萌发、幼苗生长和幼苗的抗氧化酶活性的影响,探究紫斑牡丹种子内源抑制物质的活性,为进一步研究紫斑牡丹种子休眠机理提供理论依据。结果表明:紫斑牡丹种皮和胚乳中均含有抑制受体植物种子萌发和幼苗生长的物质,且同一质量浓度下,胚乳浸提液的抑制作用强于种皮浸提液;种皮和胚乳浸提液对白菜幼苗生长的抑制作用高于小麦和绿豆;种皮和胚乳浸提液对3种受体植物幼苗根长的抑制作用大于苗高和鲜质量;种皮和胚乳浸提液对3种受体植物幼苗的SOD、CAT和POD活性均产生了一定的影响。其中,随着种皮浸提液质量浓度的提高,受体植物幼苗SOD、POD活性先上升后下降,而CAT活性持续下降;加入胚乳浸提液后,受体植物幼苗的CAT、POD活性与对照相比显著下降,SOD活性则依然随着胚乳浸提液质量浓度的升高而表现出先上升后下降的趋势。由结果可知,紫斑牡丹种皮和胚乳浸提液中均含有能抑制受体植物种子萌发和幼苗生长的物质,并且能够影响受体幼苗的抗氧化酶活性,但是紫斑牡丹种皮和胚乳内源抑制物质的活性存在一定的差异。     

根腐病菌侵染对黄芪苯丙烷途径关键酶活性的影响

以蒙古黄芪-根腐病菌（Fusarium solani和F. acuminatum）为互作体系,测定苯丙烷途径关键酶苯丙氨酸解氨酶(PAL)、肉桂酸-4-羟化酶(C4H)及4-香豆酸-辅酶A连接酶(4CL)活性的变化,以期获得黄芪抗根腐病菌侵染机制的信息,为抗病育种工作提供参考。试验采用幼苗浸根法接种病菌,分光光度法测定3种酶的动态变化。结果表明,F. solani侵染黄芪后,PAL和C4H活性与对照相比明显升高,并在7、21天出现2个酶活高峰;4CL活性则随着时间的延长持续上升,7、21天时也显著高于对照。F. acuminatum侵染黄芪后,PAL、C4H和4CL的活性均在21天显著高于对照。可见2种病原菌在侵染黄芪过程中,苯丙烷途径的关键酶被不同程度地激活,但2种病菌激活各酶的时间和规律有所差异,表明黄芪对这2种病菌的抗性机制明显不同。     

不同氮肥施用量对胶东卫矛氮代谢生理影响的研究

分析氮对胶东卫矛氮代谢生理的影响规律,明确氮肥施用后的相关酶活性变化机理,为其育苗中科学施用氮肥提供理论依据。试验在田间条件下,设置氮肥施用量分别为0 g/株(J1,CK)、9 g/株(J2)、18 g/株(J3)、27 g/株(J4)4个处理,3次重复。结果表明：5—9月J3谷草转氨酶活性分别比J1提高了64.84%、70.77%、58.52%、47.33%、57.20%,J4与J3之间无显著差异;6—9月J3谷丙转氨酶活性分别比J2提高了18.00%、30.79%、16.47%、16.83%,差异显著;谷胺酰胺合成酶活性7、9月J3显著高于J2,5—6月J2、J3、J4之间无显著差异,J2显著高于对照;5—9月J3硝酸还原酶活性分别比J2提高了20.47%、31.66%、27.32%、23.50%、34.90%,差异显著,J3与J4之间无显著差异;5—7月J3硝态氮含量分别比对照提高了73.76%、53.90%、85.95%,差异显著,8—9月J2、J3、J4之间无显著差异;6—8月,J3可溶性蛋白含量分别比J2提高了15.90%、20.09%、9.04%,差异显著。综合分析认为,J3处理可以显著提高胶东卫矛氮代谢相关酶活性,提高植株叶片内硝态氮含量和可溶性蛋白含量,效果优于J2、J4处理。     

Effects of dietary Bacillus pumilus on growth performance,innate immunity and digestive enzymes of giant freshwater prawns (Macrobrachium rosenbergii)

The present study was conducted to investigate the effects of Bacillus pumilus on the growth performance, innate immunity and digestive enzymes of the giant freshwater prawn, Macrobrachium rosenbergii. Prawns (mean weight: 1.81 ± 0.01 g) were fed different levels of B. pumilus at doses of 0, 1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ CFU/g to produce one control group and three experimental groups (G1, G2 and G3), respectively. After a 60‐day experimental feeding period, the results showed that the final weight, weight gain rate (WGR) and specific growth rate (SGR) were significantly higher in experimental groups than in the control (p < 0.05), whereas these improvements did not differ significantly (p > 0.05) among experimental groups. The improvements in phagocytic activity, respiratory burst (RBs) activity and the activity of catalase (CAT), nitric oxide synthase (NOS) and acid phosphatase (ACP) were significantly higher in G2 and G3 than in the control and G1 (p < 0.05). Further, the activity of CAT, NOS and ACP significantly increased with an increase in the dietary level of B. pumilus (p < 0.05). The activity of phenoloxidase (PO) in G3 was significantly higher than that in the control (p < 0.05). The activity of amylase was significantly higher in the groups G2 and G3 than that in the control group. G3 improved the activity of protease compared with the control (p < 0.05). In conclusion, the results of this study indicated that the potential use of B. pumilusat a dose of 1 × 10⁸ CFU/g feed could improve the growth, immunity and digestive enzymes of M. rosenbergii.     

外源NO及反向调控PEG胁迫下苜蓿萌发种子抗氧化酶及其同工酶动态的研究

以紫花苜蓿为材料,用一氧化氮供体硝普钠(SNP)及一氧化氮清除剂c-PTIO对苜蓿种子进行浸种处理,采用分光光度法和同工酶电泳技术来研究外源NO及反向调控对PEG胁迫下紫花苜蓿抗氧化酶活性及其同工酶的影响,并探讨NO调控苜蓿种子耐旱性的生理机制。结果表明:PEG胁迫下外施0.1 mmol·L^-1 SNP,第6天时较PEG处理POD活性降低了32.72%;第4天时SOD、CAT活性较PEG处理升高了10.48%、23.60%,有效缓解了PEG对紫花苜蓿萌发中种子的氧化损伤,提高其抗氧化能力。PEG胁迫下添加 c-PTIO抑制了苜蓿萌发期的抗氧化系统活性。从同工酶的谱带数量和强弱来看,POD同工酶各区带活力均随PEG胁迫时间的延长而增加,在第2天酶带只有1条,而第4天酶带呈现9条;SOD和CAT同工酶表达量变化不显著,但酶带强弱有一定变化,S3酶带随处理时间的延长表达量逐渐减弱;CAT同工酶谱带则一直保持2条带,无明显强弱变化。因此,外源NO在PEG胁迫下紫花苜蓿萌发中抗氧化酶快速响应并在维护氧自由基代谢平衡中起重要保护作用。