UV-B对人工气候室内黄瓜苗期生长、生理及抗氧化系统的影响

紫外线(UV-B)是植物生长发育的关键信号因子.过量或缺少UV-B都会影响作物的抗性、产量和品质.然而,目前植物工厂中适宜黄瓜生长的UV-B强度尚不明确.以黄瓜(Cucumis sativus L.)苗期植株为材料,研究不同强度UV-B对人工气候室内黄瓜苗期植株生长、生理和抗氧化系统的影响.结果表明:与对照相比,UV-B处理黄瓜植株高度降低4.2%~32.0%,叶片中可溶性蛋白含量降低14.2%~28.2%.3.33μmol/(m2·s)UV-B处理植株茎粗增加13.6%~22.3%,叶片中可溶性糖的含量增加22.7%~56.7%,同时激活抗氧化系统,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性分别提高16.9%~23.2%,23.8%~25.9%,34.1%~50.4%,抗坏血酸含量增加27.4%~36.4%.由此可知,3.33μmol/(m2·s)UV-B有利于人工气候室中黄瓜苗期植株的生长发育、抗氧化酶活性提高及抗氧化物质生成.     

广西平果县岩溶山地不同植物群落的土壤酶活性

为探讨平果县岩溶山地典型植物群落的土壤酶活性特征,基于调查取样与试验分析,采用相关分析、多重比较以及主成分分析方法,研究了不同植物群落间土壤酶活性的差异,分析了土壤酶活性与土壤化学性质的关系。结果表明:(1)土壤过氧化氢酶、脲酶及蔗糖酶活性的群落间差异达显著水平,显示不同植物群落对土壤酶活性产生一定影响;(2)土壤pH值与过氧化氢酶、脲酶间呈极显著正相关(p0.01),与碱性磷酸酶间呈显著负相关(p0.05);(3)4个酶活性与代表土壤肥力的土壤有机质、全氮、全磷、全钾、碱解氮及速效钾之间具有较强的相关性,但速效磷与4个土壤酶之间的相关性均未达显著水平(p0.05);(4)过氧化氢酶、脲酶及碱性磷酸酶能敏感反映土壤质量的变化,可作为本区域土壤质量评价的指标。     

不同铵硝配比对低温胁迫棉花幼苗生长及抗氧化酶活性的影响

【目的】新疆春季的“倒春寒”是严重阻碍棉花前期的生长发育,影响产量及品质的主要非生物限制因子之一,而氮素供应及氮素形态对棉花 (Gossypium hirsutum) 的生长发育具有显著影响。研究低温胁迫下不同铵硝配比对棉花幼苗抗氧化酶活性及质膜脂质过氧化伤害的影响,为通过调节氮素供应提高棉花抗寒性提供理论依据。 【方法】以‘新陆早 13 号’为供试棉花品种,在人工气候室内采用营养液水培法调节铵硝营养配比,研究了常温和低温条件下,不同铵硝配比对低温胁迫下棉花幼苗电解质渗出率、丙二醛 (MDA)、游离脯氨酸 (Pro)、可溶性蛋白质 (SP) 含量及抗氧化酶活性的影响。 【结果】常温条件 (25℃) 下,铵硝混合营养较单纯铵态氮或硝态氮营养对棉苗各器官生物量均有显著的提高 (P < 0.05),地上部分和根系干物质重量在 NH₄+/NO₃– 比为 50/50 处理时最大,纯铵营养处理时最小;对棉苗生物量的影响效果表现出铵硝混合营养处理优于纯铵或纯硝营养处理。低温胁迫 (15℃) 后棉苗各器官生物量明显减小 (P < 0.05)。低温胁迫下棉花幼苗电解质渗出率、MDA、Pro 含量显著增加 (P < 0.01),SP 含量差异不大 (P > 0.05),超氧化物歧化酶 (SOD)、过氧化物酶 (POD)、过氧化氢酶 (CAT) 活性显著降低 (P < 0.01),抑制了棉花幼苗的生长发育。相同温度条件下,棉花幼苗电解质渗出率和 MDA 含量均随营养液中铵营养比例的增加而呈现出先减小后增大的变化趋势,在营养液中 NH₄+-N/ NO₃–-N 比例为 50/50 处理时达到最小,纯硝营养处理次之,纯铵营养处理最大;而同温下 SP、Pro 含量先增加后减少,NH₄+-N/NO₃–-N 为 25/75 最大。增铵营养明显增强了 SOD、CAT 活性 (P < 0.01),POD 活性则随着 NH₄+-N/NO₃–-N 比例增加表现出先降低后升高的趋势。 【结论】低温胁迫下,铵硝混合营养降低了棉花幼苗电解质渗出率和 MDA 含量,增加了渗透调节物质积累,提高了抗氧化酶活性,降低了脂质过氧化伤害,增强棉花幼苗对低温的抗性,尤其 NH₄+-N/NO₃–-N 比例为 50/50 的营养液效果更明显。     

Growth and Biochmical Studies of Mrigal Fish (Cirrhinus mrigala) Fed Graded Levels of Oil

A 45-day experiment was carried out to evaluate the growth performance,digestive enzymes activity and biochemical response of Cirrhinus mrigala fed graded levels of oil.Three isonitrogenous purified diets(6%,8%and 10%of oil)were formulated.A total of 108 juveniles of Cirrhinus mrigala(5.95±0.25)g were equally distributed in triplicate groups in nine plastic tanks of 100 L capacity and fed under natural light cycle.Growth performance of the fish significantly reflected the effect of inclusion levels of oil tested but the diet with 8%lipid had the best significant growth performance[%weight gain,Feed Conversion Ratio(FCR)and Specific Growth Rate(SGR)],across different experimental groups.Levels of secretion of digestive enzymes in the fish fed different experimental diets resulted in significant values of(p0.05)amylase and lipase,while Aspartate transaminase(AST),Alanine transaminase(ALT),Lactate dehydrogenase(LDH)and Malate dehydrogenase(MDH)values in the muscle and liver decreased significantly(p0.05)as the levels of oil in the diet increased.However,serum biochemical parameters did not record any significant difference(p0.05)with the exception of the total lipid across diets.The study confirmed the inclusion effect of graded levels of oil in juvenile Mrigal diet,but the inclusion should not be more than 8%to avert growth depression.     

保水剂施用方式对土壤酶活性及马铃薯产量的影响

【目的】研究不同保水剂施用方式对内蒙古西部半干旱偏旱地区土壤酶活性及马铃薯产量的影响,以筛选出合适的保水剂及施用方式。【方法】以聚丙烯酰胺(PAM)和聚丙烯酸钾(PAA-K)为材料,设不施保水剂(CK)、穴施PAM、沟施PAM、穴施PAA-K、沟施PAA-K 5个处理,分析不同保水剂及其施用方式下马铃薯不同生育时期、不同土层土壤过氧化氢酶、脲酶、蔗糖酶活性和产量的变化。【结果】土壤过氧化氢酶、脲酶、蔗糖酶活性随马铃薯生育时期的推进呈现"单峰"曲线变化,均于马铃薯块茎膨大期达峰值。与CK相比,施用保水剂处理均能提高土壤过氧化氢酶、脲酶、蔗糖酶活性,且对于同一种保水剂,穴施处理提高幅度大于沟施处理。在马铃薯块茎膨大期,穴施PAM、穴施PAA-K、沟施PAM、沟施PAA-K处理0~10cm土层的土壤过氧化氢酶活性较对照分别提高了12.92%,11.97%,9.06%和6.02%,土壤脲酶活性较对照分别提高了12.38%,2.33%,0.86%和0.31%,土壤蔗糖酶活性较对照分别提高了22.99%,17.03%,20.50%和18.34%,土壤过氧化氢酶、脲酶、蔗糖酶活性随土层的增加逐渐降低。与CK相比,施用保水剂显著提高了马铃薯产量和商品薯率,降低了小薯率。穴施PAM、穴施PAA-K、沟施PAM、沟施PAA-K分别较对照增产12.08%,10.45%,7.37%和5.22%。【结论】施用保水剂PAM、PAA-K均提高了土壤过氧化氢酶、脲酶、蔗糖酶活性及马铃薯产量和商品薯率,降低了小薯率,其中穴施PAM效果最好。     

Long-term agricultural activity affects anthropogenic soil on the Chinese Loess Plateau

Anthropogenic activities largely influence the soil quality of agricultural fields and the composition of soil. Samples of typical anthropogenic Loutu soil in the Guanzhong area of the Loess Plateau, Shaanxi Province, China were collected and measured for soil compaction, bulk density, total organic carbon(TOC), active organic carbon(AOC), and soil enzyme activities to investigate spatial variations in soil quality. The results indicate that soil compaction and bulk density increased with increasing distance from the farm village, whereas soil TOC, AOC, and soil enzyme activities firstly increased and subsequently decreased with increasing distance from the farm village. All of the tested parameters presented clear concentric distribution. Vertically, soil compaction and bulk density in the topsoil were lower than those in the subsoil, but all other tested parameters in the topsoil were significantly higher than those in the subsoil. In addition, there was a significant positive correlation between organic carbon content and enzyme activities, confirming that the spatial distribution of Loutu soil characteristics has been affected by long-term anthropogenic activities to some extent. The results of this study imply that the use of farmyard manure and appropriate deep plowing are important and effective ways to maintain and improve soil quality.     

广西杉木连栽幼林根际与非根际土壤特性研究

采用配对样地法对广西连栽杉木幼林不同栽植代数(一代林G1、二代林G2)的根际土和非根际土进行了土壤特性的分析研究,为连栽杉木人工林经营与可持续发展提供理论依据。结果表明:土壤pH值、有机质、全N、全P、水解性N、有效P、速效K、交换性Ca~(2+)、有效Fe、有效Mn含量均表现为G2G1,根际土(R)非根际土(S),而土壤全K含量则反之。杉木连栽对林地土壤养分状况、酶活性和微生物具有一定影响。土壤酶活性表现为G2G1,根际土(R)非根际土(S)。无论是在根际土还是非根际土,土壤微生物优势种均为细菌,微生物总数、细菌、放线菌、真菌数量表现为G1G2;栽植代数增加,细菌所占微生物总数比例下降,而放线菌所占比例则有明显增加趋势。     

Effect of Fermented Corn Stalks on Growth Performance and the Growth Promotion Mechanism in Otter Rabbit

This experiment was conducted to research the growth promoting effects of fermented corn stalks with compound bacteria on otter rabbit. The daily feed of otter rabbit was based on fermented corn stalks (roughage ration composed mostly of fermented corn stalks). The growth performance, intestinal tract bacteria and the digestive enzyme activities of otter rabbit were studied. A total of 150 health otter rabbits, 9 weeks old, weighted about (1.90±0.14) kg, were allotted to 2 groups (control group and experimental group) for 10 days preliminary trial period and 30 days trial period. The results were as follows:Compared with control group, the average daily gain (ADG) increased by 14.60% (P<0.05) and F/G decreased by 10.50% (P<0.05) of the experimental group; In intestinal tract of otter rabbit, the number of E.coli were reduced by 46.13% (P<0.01), the number of Lactobacillus, Bifidobacteria and Bacillus increased by 30.64% (P<0.05), 29.27% (P>0.05) and 39.23% (P<0.01),respectively; The activities of protease, amylase, cellulose enzyme and glucanase were increased by 23.20%(P<0.05), 32.96% (P<0.05), 12.63% (P<0.01) and 21.09% (P<0.05), respectively. In conclusion, the fermented corn stalks could promote the growth and improve the intestinal tract ecological environment of the otter rabbit. The results established the theoretical foundation for fermented corn stalks feeding on otter rabbit.     

黔中地区土壤酶活性对岩性的响应

选择黔中喀斯特地区6种不同岩性(玄武岩、石英砂岩、长石石英砂岩、变余砂岩、第四纪红色黏土、煤系砂页岩)发育的土壤为研究对象,通过采样并测定其土壤酶活性指标、土壤肥力指标,分析土壤酶活性及其与肥力因子的关系。结果表明,(1)土壤酶活性对岩性的响应,除淀粉酶外,其他土壤酶活性指标均存在明显差异;(2)玄武岩发育的土壤酶活性表现最好,脲酶、过氧化氢酶、多酚氧化酶活性最高;(3)土壤酶活性与所对应的肥力因子间密切相关。     

杜梨硝酸盐转运酶NRT2基因的克隆与生物信息学分析

[目的]克隆杜梨硝酸盐高亲和性转运酶NRT2基因。[方法]以杜梨叶片为试验材料,采用CTAB法提取总RNA,反转录成c DNA,运用3'-RACE和5'-RACE技术,克隆获得杜梨硝酸盐转运酶NRT2基因的全长,并运用生物信息学技术对硝酸盐转运酶NRT2基因进行了分析。[结果]杜梨硝酸盐转运NRT2基因c DNA全长为1 422 bp,可编码473个氨基酸,分子式为C2346H3631N589O637S26,相对分子质量为51 112.7,等电点(p I)为7.03。[结论]该试验为进一步研究梨氮素代谢提供了基础资料。