H2O2对不同大豆品种低温萌发及主要抗氧化酶活性的影响

大豆喜温,对低温敏感,播种后易遭受冷害造成减产.冷害与低温诱发植物活性氧的形成增加并抑制其清除能力有关.但研究表明当环境胁迫诱导活性氧增加的初期,也诱导清除能力的增强,H2O2参与这个过程的诱导.然而外源H2O2处理对大豆种子低温萌发的效应、对抗氧化酶活性的影响以及萌发过程中大豆种子内源H2O2含量的变化还不清楚.以冷敏感型大豆品种沈农8号、沈农9411和耐冷型大豆品种铁丰31、Kottman为材料,用10,20,50,100和200 mmol L-1的H2O2进行浸种处理后,在低温(5℃)下萌发.当外源H2O2浓度低于50 mmol L-1时,各浓度处理都提高发芽率,降低电解质外渗率,提高超氧化物酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性;当H2O2浓度高于50 mmol L-1时,抗氧化酶活性随H2O2浓度的增加而降低,耐冷品种的抗氧化酶活性始终高于冷敏感品种;在萌发过程中,内源H2O2含量随H2O2处理浓度的升高而增加.表明外源H2O2可能通过大豆内源H2O2含量的提高诱导抗氧化酶活性的增强,从而减轻低温伤害,提高在低温下的萌发能力.     

低钾胁迫对不同钾营养效应型大豆保护酶系统的影响

以四种钾营养效应型大豆品种(系)(铁丰31号、沈农6号、铁95068-5、GD1617)为试验材料,设置两个钾浓度处理,研究低钾胁迫对大豆整个生育期细胞保护酶系统的影响.结果表明:在低钾胁迫下,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性均有不同程度的升高.SOD的活性高峰出现时期最早,CAT次之,POD出现最晚.从敏感型来看,耐性系数高的不敏感型品种(系)CAT与POD的活性差异明显高于耐性系数低的敏感型品种(系),SOD活性差异则不甚显著.由此,本文认为大豆钾营养敏感型间的差异可以通过保护酶系统活性差异得以表现.     

微生物降解褐煤产生的黄腐酸对大豆种子萌发及主要抗氧化酶活性的影响

研究了微生物降解褐煤产生的黄腐酸(FA)对大豆萌发过程中过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)的影响,以期揭示FA促进种子萌发的机理.结果表明:适宜浓度FA可以提高大豆萌发率,显著增加种子POD、CAT及SOD的活性.FA浓度为100 mg·kg-1时,CAT、SOD活性分别提高32.15%、24.5%;FA浓度为200 mg·kg-1时,大豆萌发率比对照提高34.6%,并且POD活性增加19.92%.而高浓度的黄腐酸对大豆萌发及抗氧化酶活性产生抑制作用.FA表现出类似生长调节剂的性质,适宜浓度的黄腐酸能提高大豆种子的萌发率,显著提高其抗氧化酶的活性,对种子萌发起到促进作用.     

PEG模拟干旱对大豆抗氧化酶活性及抗氧化能力的影响

以黑农44和黑农65大豆为试验材料,采用20%浓度的PEG-6000模拟干旱胁迫,研究干旱胁迫对大豆叶片开花期抗氧化酶活性及抗氧化能力的影响。结果表明:随处理时间的延长,大豆叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性、总抗氧化能力(T-AOC)、超氧阴离子清除能力(SASC)和羟自由基清除能力(HRS)均随着处理时间的延长而呈先升高后降低的趋势;在处理时期内,对照组与处理组中,抗旱品种黑农44的各项指标均高于敏感型品种黑农65。相关性分析可知:黑农44和黑农65的CAT活性与SOD活性,SASC与CAT活性,HRS与SOD活性,HRS与SASC均呈极显著正相关,HRS与T-AOC显著正相关;耐旱型品种黑农44的T-AOC与POD活性,SASC与POD活性,HRS与CAT活性均呈极显著正相关,而敏感型品种黑农65 T-AOC与POD活性呈现显著正相关,SASC与POD活性,HRS与CAT活性正相关均不显著;黑农44的SASC与SOD活性显著正相关,黑农65则表现为极显著正相关,耐旱型品种黑农44抗氧化酶和抗氧化能力之间的相关程度高于敏感型黑农65。试验表明抗旱大豆品种具有较强的抗氧化酶活性和抗氧化能力。     

低温胁迫下木薯几种保护酶活性变化及其与耐寒性的关系

以木薯华南8号和6号组培苗为材料,测定不同温度和低温胁迫时间处理下的细胞保护酶中超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT的活性.结果表明,随着温度的不断降低和低温胁迫时间的延长,2个木薯品种的SOD酶活性呈下降趋势,POD和CAT先上升后下降,种间差异不显著.     

干旱胁迫下外源褪黑素对大豆苗期抗氧化酶的活性影响

以干旱敏感型大豆品种绥农26为材料。通过盆栽试验分析了干旱胁迫条件下喷施褪黑素(100 μmol/L)对大豆苗期叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)活性的影响。试验结果表明,干旱胁迫会提升SOD、CAT、POD、APX的活性。在干旱胁迫条件下,通过叶面喷施褪黑素显著提高了SOD、CAT、POD、APX的活性。因此外源褪黑素提高了干旱胁迫条件下大豆苗期抗逆能力。     

O3浓度升高和UV-B辐射增强对大豆叶片抗氧化酶活性及POD同工酶的影响

以大豆品种铁丰29为材料,利用开顶式气室(OTCs)研究了O3浓度升高和UV-B辐射增强单独胁迫及复合胁迫下大豆叶片抗氧化酶(SOD、POD和CAT)活性及POD同工酶谱带的变化.结果表明:O3处理大豆叶片SOD、CAT和POD活性均低于对照;UV处理下,大豆叶片SOD、CAT、POD活性也均低于对照,但基本高于O3处理;O3及UV复合处理下,加剧了SOD、CAT、POD活性的减弱.对POD同工酶研究发现,在分枝期,O3处理产生Ⅰ条新谱带,开花期和结荚期均比分枝期多2条谱带,并且受胁迫处理的POD酶谱带与对照相比颜色较浅,说明在整个生育期,胁迫处理下的大豆叶片POD同工酶活性受到抑制.     

镁对大豆叶片抗氧化代谢的影响

以大豆品种浙春2号、浙春3号和9703为材料,采用土培实验方法,设置不同的镁离子处理水平,研究五 叶期和盛花期大豆叶片叶绿素含量、脯氨酸( Pro)含量、丙二醛(MDA)含量、质膜透性(MP)和抗氧化酶( SOD、POD 和CAT)活性的变化。结果表明,大豆叶片叶绿素含量在五叶期时与镁离子浓度成正相关,盛花期时与镁离子浓度 负相关;在缺镁(0. 00mg/kg)条件下,大豆叶片的脯氨酸含量、MDA含量、质膜透性、超氧化物歧化酶( SOD)和过氧 化物酶( POD)活性较其它处理高,过氧化氢酶(CAT)活性较低;施镁则能显著降低大豆叶片的脯氨酸含量、MDA 含量和质膜透性,其中镁离子浓度60. 00mg/L的效果最好。3个大豆品种五叶期时脯氨酸和MDA含量较对照(0. 00mg/kg)降低1. 38%～22. 96%和12. 60%～44. 50% ,盛花期时则下降了11. 11% ～57. 90%和9. 87% ～71. 61%; 质膜透性五叶期时较对照下降了7. 19% ～38. 61% ,盛花期时则降低了21. 79%～46. 10%。SOD、POD和CAT对镁 的反应存在明显的不同。大豆品种对镁的反应存在一定的基因型差异,浙春3号对镁最为敏感,浙春2号次之, 9703对镁不太敏感。     

低温和UV-B复合胁迫对小麦幼苗抗氧化酶和渗透调节物质的影响

为揭示UV-B辐射与早春低温复合环境对小麦生理生化的影响,以小麦品种龙麦26为材料,分析了低温、UV-B及二者复合胁迫下小麦幼苗抗氧化酶活性和渗透调节物质含量。结果表明,与对照(正常生长条件)相比,低温下小麦丙二醛(MDA)和可溶性糖含量及过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、苯丙氨酸解氨酶(PAL)活性显著升高,过氧化物酶(POD)活性显著降低,原初光能转化效率(F_v/F_m)、脯氨酸含量未发生显著性变化;UV-B处理诱导MDA和脯氨酸含量及POD、PAL活性显著增加,但显著降低F_v/F_m和可溶性糖含量,CAT和SOD活性没有发生显著的变化;低温和UV-B复合处理后SOD和PAL活性显著增加,而F_v/F_m、CAT和POD活性及可溶性糖含量显著下降,MDA和脯氨酸含量却没有显著变化。以上结果说明,小麦幼苗不同代谢生理指标对低温、UV-B及二者复合胁迫响应程度和方式不同。     

盐胁迫对马铃薯出苗及苗期生物学性状的影响

马铃薯作为重要的粮、菜兼用型作物,深受南疆少数民族的喜爱。马铃薯属盐敏感型作物,为研究其耐盐机制,选育耐盐品种,试验采用盆栽方法,研究了4个马铃薯品种在土壤含盐量(NaCl)分别为0(对照)、0.3%(处理1)、0.6%(处理2)条件下的出苗天数、出苗率、苗期株高、SPAD值、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性及超氧化物歧化酶(SOD)活性的变化。结果表明,在0～0.6%的土壤含盐量(NaCl)下,随着土壤含盐量增大,马铃薯出苗延迟,出苗率、株高、SPAD值、POD活性、SOD活性、CAT活性均降低,0.3%处理下出苗较对照平均延长3.25 d,出苗率降低26.67个百分点;0.6%土壤含盐量出苗较对照平均延长5.75 d,出苗率降低70.00个百分点。在盐胁迫处理下,‘龙薯10号’出苗率、SPAD值、抗氧化酶活性均高于其他品种。研究结果可为马铃薯耐盐品种的筛选和培育提供参考。     

THE EFFECT OF THE TIME AND LEVEL OF INJECTION OF ANHYDROUS AMMONIA ON THE PRODUCTIVITY OF GRASSLAND

Four levels of nitrogen, 188, 285, 358 and 392 kgJ.ha (150, 225, 285 and 350 units/ac) supplied as anhydrous ammonia were injected on each of four occasions, 18 Dec, 5 Feb., 12 Mar. and 16 Apr. DM and CP yields were estimated at each of three harvests taken on 4 June, 19 July and 28 Sept Total DM yields showed only a 10% difference between the highest yielding injection date, 12 Mar., which yielded 12270 kg/ha (10946 Ib/ac) and the lowest, 16 Apr., which yielded 11169 kgJ.ha (9963 Ib/ac). Early injection of ammonia promoted growth during the late spring and later injections resulted in increased yields at the two later harvests. The responses per kg fertilizer N were 11.9 kg DM (10.8 lb/unit) and 3.6 kg CP (3–3 Ib/unit). It was concluded that ammonia should be applied to grassland before April and, preferably, during March, for maximum yields of DM and CP.     

THE USE OF THE IN VITRO TECHNIQUE IN THE DETERMINATION OF THE DIGESTIBILITY OF GRASS/LEGUME MIXTURES

The in vitro dry-matter digestibility was determined of two samples of Digitaria decumbens , one sample of Medicago sativa , and one sample of Trifolium repens and nine mixtures prepared from these samples.
When the results were compared with in vivo digestibilities the standard errors of the regressions for the three combinations of legume, grass and legume/grass mixtures were ±0.6, ±0.6 and ±1.5 percentage units, respectively.
It is considered that in vivo digestibility of mixtures of grasses and legumes can be estimated by the in vitro technique, provided that suitable grass and legume standards are included.     

THE USE OF THE FORAGE HARVESTER IN THE IMPROVEMENT OF ROUGH GRAZING

Considerable improvement has been achieved in rough grazings by fairly frequent close mowing with the forage harvester or flail mower, particularly when combined with manuring and surface seeding.
The implement has proved capable of tackling very tough vegetation and converting it into grazing swards of fair value and good botanical composition. Undesirable species have been largely eliminated by treatment over two growing seasons.
The method is believed to compare favourably in cost with sward renovation by cultivation or by herbicides.     

THE ROLE OF GREEN SOILING IN THE ECONOMY OF THE DAIRY FARM

With modern machinery and modem techniques of grass production, mechanical-or zero-grazing offers a means of utilizing the crop to perfection. Whether this results in enhanced profits depends largely upon the farm and the specific circumstances. It may, it may not. What is evident is that the health of the cows is not affected by an unnatural manner of summer feeding; the sward, per se, may be improved by the regular and uniform defoliation; and under conditions of intensive production and the vital need to use profitably every blade of grass, as for instance on small, highly-rented farms, the practice of zero-grazing merits the most careful consideration. It cannot lightly be dismissed as merely a new fad.     

光周期对马铃薯块茎形成的影响及对激素的调节

马铃薯出苗后接受１个月的每日８小时短日照处理并与当时自然光照长度进行比较，研究光照长度对块茎形成及内源激素②的影响，探讨块茎形成与激素水平的关系。结果表明：短日照处理使块茎形成显著提早，但使结薯数减少，植株茎叶生长受抑，块茎淀粉含量降低；短日照处理使叶片中ＡＢＡ含量提早增高，ＧＡ３含量提早减少，ＧＡ３与ＡＢＡ的比值提早显著降低．     

菜用大豆荚皮性状与产量形成的关系

利用菜用大豆的四个杂交组合,对其荚皮性状即荚皮的长、宽、表面积以及荚皮的内膜层、革质层等性状进行试验观察,并分别与子粒、产量进行相关分析.荚皮的长、宽、表面积、荚皮内膜层、荚皮革质层与产量有极显著正相关,荚皮表面积与产量的相关系数达0.6795**,内膜层鲜重与产量的相关系数和通径分析均达到0.8433**.革质层与子粒的相关性较大,百荚革质层的鲜重、风干重与百粒重的相关系数达0.6681**、0.6112**,荚皮厚与子粒鲜、干重及产量均呈极小不显著的正负相关(-0.0706～0.2810).在育种工作中应重视荚皮的表面积、内膜层和革质层等对产量和产品质量的影响.     

THE EFFECT OF TEMPERATURE IN THE MASS ON THE CHEMICAL COMPOSITION OF SILAGE

The effect of temperature on silage quality was investigated in a series of trials over a period of three years.
The results indicated that when conditions in the silage were favourable for the formation of lactic acid, either through treatment or because of the herbage itself, low temperatures in the mass had no adverse effect on silage quality.
Some results suggest that, with chopped or lacerated silage, low maximum temperatures are associated with better quality silage. The results, however, were not entirely consistent.
There appeared to be little or no advantage in allowing unchopped silage to heat to 100°F.