铝对大豆叶片水势和生理特性的影响

以2个大豆{Glycine max(L.)Merrill}品种华春18,浙春3号为材料,设置不同的铝浓度进行土培试验,研究铝对大豆叶片水势和一些生理特性的影响。结果表明:高浓度的铝对大豆生长明显不利。随铝浓度的增加,大豆叶片水势略有下降;蛋白质含量在三叶期有所上升,然后在五叶期开始下降;叶绿素含量除三叶期外都有明显下降;二个大豆品种的SOD活性变化明显不相同。从种间差异性来看,浙春3号抗铝胁迫的能力大于华春18。     

大豆种质耐低磷与耐铝毒部分指标及其相互关系的研究

通过溶液培养试验 ,对来源于华南酸性土壤的 5个大豆品种的地上部及根部耐低磷及耐酸铝部分指标进行了系统的研究。研究结果表明 ,大豆在磷效率和耐铝毒特性方面存在着一定的差异 ,大豆品种 6 2号、乐昌及广州大粒具有较高的磷效率和耐铝毒特性。在低磷及铝毒胁迫下它们具有较高的生物量、磷含量、叶面积、叶绿素含量、总酸分泌量以及主根长。低磷和铝毒胁迫严重影响地上部磷的吸收 ,高磷能缓解铝毒。铝浓度不同处理大豆的地上部无显著差异 ;但在铝毒胁迫下 ,根部的铝浓度比地上部高 5～ 6倍 ,且品种间存在显著差异。本研究初步确定了大豆耐低磷与耐铝毒的相关关系     

Al3+对大豆根边缘细胞释放与活性的影响

以两个大豆 [Glycine max (L.) Merr.] 品种（耐铝性大豆浙春2号和铝敏感性大豆华春18）的边缘细胞为材料,比较研究了Al3+对根尖原位边缘细胞释放以及对离体边缘细胞的毒害作用。结果显示,0、100、200 μmol/L Al3+处理后,浙春2号和华春18的根尖边缘细胞在水中均易分散,华春18的边缘细胞在300 μmol/L的Al3+处理时已聚集成团不易分散,而浙春2号的边缘细胞在400 μmol/LAl3+处理时才不易分散。Al3+对离体边缘细胞有明显的毒害作用,100 μmol/L Al3+处理1～ 6 h就表现出细胞死亡症状,毒害作用最大时出现在6 h之后,其中Al3+对华春18的毒害作用略高于浙春2号。系列浓度Al3+ （0、100、200、300、400 μmol/L Al3+）处理,100 mol/ L Al3+处理的离体边缘细胞存活率已出现较大幅度的下降,至400 mol/L Al3+处理时,浙春2号和华春18的相对存活率分别只有对照的45.9%和39.0%。 说明外界Al3+浓度升高不仅影响边缘细胞的释放,而且显著降低离体边缘细胞的存活率,毒害作用最大时出现在6 h之后。大豆品种间细胞对Al3+的反应存在一定差异,随时间变化,差异最大时在6 h。     

铝胁迫下大豆根系分泌物对根际土壤微生态的影响

通过对19个不同基因型大豆品种的耐铝性筛选实验,选择耐铝型的浙春2号和敏感型的浙春3号作为实验材料;设置5个铝处理浓度(0,0.2,0.4,0.6,0.8 g kg-1,即土壤总Al3+浓度分别为0.293,0.493,0.693,0.893,1.093 g kg-1)土壤,大棚种植大豆30d后,取大豆根际、非根际土壤和外源根系分泌物作用下的土壤样品,对各类微生物生理群进行分析,同时测定土壤呼吸速率、纤维分解作用、氨化作用、硝化作用,以及酸性磷酸酶、过氧化氢酶和蔗糖酶等土壤重要酶类的活性。结果显示,土壤铝含量较低条件下(0.2,0.4g kg-1),大豆根系分泌物的应激分泌促使土壤微生物数量增多、微生物物质转化能力增强和土壤酶活性增大;土壤铝含量较高(0.8 g kg-1)时,根系分泌物的分泌相对受抑制,土壤微生物活性和土壤酶活性相应地受到抑制。实验结果还表明,外源根系分泌物也能影响土壤微生态,引起土壤微生物数量和土壤酶活性的变化,以及各种土壤生化作用(如硝化作用等)的改变,显示出一定的缓解铝毒能力,从而减少铝毒对植物的伤害。     

钼、硼对大豆光合效率的影响

以大豆(Glycinemax)浙春3号、浙春2号和3811等3个品种为材料,设置了不同的钼、硼处理(低钼低硼,施钼,施硼和钼、硼同施),研究了钼、硼对大豆光合效率的影响。结果表明,施钼或硼促进了大豆叶面积的扩大,提高了大豆光合速率和荚的可溶性糖含量,延缓了大豆生育后期叶绿素的衰退,增强大豆的呼吸作用,降低茎和叶的可溶性糖含量,从而提高了大豆的光合效率,且钼、硼同施作用更大。在对大豆光合叶面积、叶绿素含量和呼吸作用的影响强度上,钼的作用于大硼;对大豆光合速率和可溶性糖含量的影响强度,硼的作用大于钼。3个大豆品种对钼、硼的反应存在一定的基因型差异。     

几个大麦品种(系)的耐盐性评价

以发芽势(率)盐害指数、发芽指数下降率、产量及构成因素等为指数,对苏啤3号、苏啤4号、单二、扬农啤5号、盐99098、盐丰一号、C2118、西引二号等几个大麦品种(系)进行了耐盐性试验研究。试验结果表明:低NaCl胁迫浓度对参试品种(系)的影响不大,高盐胁迫(NaCl浓度大于60mg/ml)导致上述指标明显下降。品种不同对盐分胁迫的反映不同。芽期耐盐性综合评价结果得出参试品种(系)的耐盐顺序依次为C2118=盐丰一号>扬农啤5号>苏啤4号>西引二号>单二>苏啤3号>盐99098;盆栽试验耐盐性顺序依次为C2118>盐丰一号>苏啤4号>扬农啤5号>西引二号>单二>盐99098>苏啤3号。芽期和成熟期均耐盐的大麦品种(系)为C2118、盐丰一号、苏啤4号、扬农啤5号,可作为耐盐品种(系)直接在盐碱土种植或作为耐盐种质资源利用。     

农杆菌介导的大豆成熟胚芽尖遗传转化体系的优化

以大豆品种‘浙春3号’的胚芽尖为受体材料,利用农杆菌介导法转化抗逆相关大豆转录因子GmGT-2A,为探讨过量表达该基因以提高大豆对非生物胁迫的抗逆性准备材料,通过研究预培养时间、共培养培养基的6-BA浓度、侵染时间等因子对转化效率的影响,系统优化了大豆的成熟胚芽尖转化体系。单因素优化实验结果表明：预培养时间、6-BA浓...     

铝诱导大豆根系有机酸分泌的能量消耗的定量研究

铝诱导大豆根系有机酸分泌是其解铝毒的一种重要机制,该过程需要消耗能量,然而有关能量消耗的定量研究还未见报道。本文比较了铝胁迫条件下,两个大豆品种根尖有机酸分泌、 腺苷酸、 无机磷、 细胞质pH值等指标的变化。结果表明,铝处理（25 mol/L）明显诱导大豆根系苹果酸和柠檬酸的分泌。与对照相比,铝胁迫条件下中豆32和本地2号的根尖ATP含量分别降低40.1%和13.2%,根系细胞质子跨膜电化学势差分别增加1711.8和570.6 J/mol,然而,根尖无机磷浓度变化差异不大。运用Nernst-Gibbs方程定量计算自由能变化,发现中豆32和本地2号根尖细胞自由能分别消耗16.13 kJ/mol和14.59 kJ/mol, 中豆32分泌单位苹果酸和柠檬酸的能量消耗分别为0.96 kJ/mol和3.15 kJ/mol,本地2号则为2.01 kJ/mol和5.68 kJ/mol。这表明不同耐铝性大豆品种分泌有机酸消耗的能量存在差异,该结果为筛选耐铝作物品种提供了新思路。     

过量Fe2+对大豆叶肉细胞超微结构的影响

研究了在过量Fe2+胁迫下,2个大豆[Glycine.max(L.)Merrill]品种(浙春3号和1601)叶肉细胞超微结构的变化。观察发现,随着铁浓度的增加,浙春3号叶肉细胞超微结构损伤不断加重,叶绿体中出现巨型淀粉粒、被膜破损;线粒体嵴突减少或混乱,双层膜破裂;细胞质中液泡内含有膜系统片段;质膜向内折叠成波浪状。1601叶肉细胞在遭受低、中度铁毒时,叶绿体受损较轻,在高浓度铁毒下出现叶绿体被膜破裂、线粒体空泡化等现象。这些结果表明,过量Fe2+主要对细胞膜结构产生毒害作用;浙春3号对铁毒较为敏感。     

铬胁迫对青菜（Brassica chinensis L.）植物螯合肽含量及抗氧化特性的影响

选用不同耐铬胁迫青菜品种春油1号和青伏令,采用不同浓度Cr3＋处理,测定青菜抗氧化酶活性及植物螯合肽含量等生理指标。结果表明,随着Cr3＋处理浓度升高,两种青菜叶片抗氧化酶活性、酸溶性SH、植物螯合肽（PCs）及谷胱甘肽（GSH）含量均呈增加趋势（P〈0.05）,高浓度Cr3（＋300 mg.L-1）处理下,耐铬胁迫较弱的青伏令叶片SOD、POD、CAT活性分别比对照增加了24.2%、41.7%、21.4%,耐铬胁迫较强的春油1号分别比对照增加了37.2%、70.7%、43.0%,并且PCs含量是对照的3.17倍,明显高于耐铬胁迫较弱品种青伏令（1.71倍）。Cr3＋处理下耐铬胁迫较强的青菜品种春油1号表现出相对较高的抗氧化酶活力及非酶物质含量,不同品种青菜对铬胁迫的生理差异较大。     

空间坏境对大豆主要农艺性状及蛋白品质的诱变效应

以“实践八号”育种卫星搭载的3个大豆品种中黄28、中黄29、中黄31为材料,调查了空间诱变后代SP1、SP2代的主要农艺性状分析检测SP2、SP3种子的蛋白质组分（11S/7S球蛋白）、Kunitz胰蛋白酶抑制剂（SKTI）等品质性状分析检测,以为利用空间诱变技术改良大豆品质提供理论依据。结果表明,3个大豆品种对空间环境的反应敏感性不同,中黄28和中黄29的SP1代分别获得3株和12株变异株,变异率分别为0.417 %和1.667 %,而中黄31的SP1代没有发现变异植株,且中黄28的2株（01-SP2-1、01-SP2-2）和中黄29的5株（02-SP2-2、02-SP2-5、02-SP2-6、02-SP2-7、02-SP2-8）变异株在SP2代发生性状分离;空间环境使大豆11S 蛋白亚基发生变异,SKTI基因发生突变。空间诱变既可改良农艺性状,也可改良品质性状。     

Citrate Secretion Induced by Aluminum Stress May Not be a Key Mechanism Responsible for Differential Aluminum Tolerance of Some Soybean Genotypes

Abstract

Eighteen soybean genotypes differing in aluminum (Al) tolerance were used to investigate genotypic differences in Al-induced citrate exudation and its role in Al tolerance. Aluminum accumulation and localization in soybean roots were examined by analysis of total Al and hematoxylin staining. Soybean genotypes exhibited a wide range of Al tolerance. Based on relative root elongation, several Al-tolerant genotypes from Brazil such as B1, B10, and B15 were more tolerant than the Al-tolerant PI 416937 (PI) and Perry. All soybeans exuded citrate in response to Al stress, and some Al-sensitive genotypes secreted more citrate than tolerant ones, showing no correlation between the Al tolerance and Al-induced citrate exudation. Further study found that both copper (Cu) and cadmium (Cd) stimulated citrate and malate exudation in soybean, indicating that organic acid secretion is not specifically induced by Al. Aluminum concentrations were significantly higher in 2–3 and 3–4 cm of segments than that in 0–1 and 1–2 cm segments under 15 μM AlCl₃. Both the root mature zone and apex were heavily stained by hematoxylin after exposure to 10, 15, or 20 μM AlCl₃ (24 h), whereas root elongation zone was not stained. After exposure to 50 μM AlCl₃ for 20 min, the Al-tolerant PI was less stained by hematoxylin than the Al-sensitive Young, suggesting that Al accumulation in root apices seem to be an immediate response to Al stress, and related to differential Al sensitivity. Present results suggest that citrate secretion induced by Al stress may not be a key mechanism responsible for the differential Al tolerance of some soybean genotypes and other mechanism(s) conferring Al exclusion should exist and operate immediately after exposure to Al stress.     

Chemical composition of glyphosate-tolerant soybean 40-3-2 grown in Europe remains equivalent with that of conventional soybean (Glycine max L.)

The composition of glyphosate-tolerant (Roundup Ready) soybean 40-3-2 was compared with that of conventional soybean grown in Romania in 2005 as part of a comparative safety assessment program. Samples were collected from replicated field trials, and compositional analyses were performed to measure proximates (moisture, fat, ash, protein, and carbohydrates by calculation), fiber, amino acids, fatty acids, isoflavones, raffinose, stachyose, phytic acid, trypsin inhibitor, and lectin in grain as well as proximates and fiber in forage. The mean values for all biochemical components assessed for Roundup Ready soybean 40-30-2 were similar to those of the conventional control and were within the published range observed for commercial soybean. The compositional profile of Roundup Ready soybean 40-3-2 was also compared to that of conventional soybean varieties grown in Romania by calculating a 99% tolerance interval to describe compositional variability in the population of traditional soybean varieties already on the marketplace. These comparisons, together with the history of the safe use of soybean as a common component of animal feed and human food, lead to the conclusion that Roundup Ready soybean 40-3-2 is compositionally equivalent to and as safe and nutritious as conventional soybean varieties grown commercially.     

黑豆种质苗期耐荫性评价及其根系对弱光胁迫的响应

玉米-大豆复合种植是西南地区重要的生态种植模式之一,而目前耐荫型专用黑豆种质十分匮乏,黑豆的耐荫机理也尚不清楚,这严重影响了该模式的进一步推广。本研究旨在建立黑豆苗期耐荫性评价数学模型,筛选出能够判断黑豆耐荫性的有效指标,并探讨不同耐荫型黑豆根系对弱光胁迫的响应差异,为耐荫型黑豆种质的选育及耐荫机理的阐释奠定基础。试验以23个黑豆种质为研究材料,采用盆栽试验方法,设置自然光和遮荫2个处理。在黑豆植株V3期测定株高、茎粗、下胚轴长度、叶片干重、茎干重、主茎节数、总根长、根表面积、总根体积等形态指标和光合参数、叶绿素荧光参数等生理指标。采用多元统计方法建立黑豆苗期耐荫性评价模型,并根据评价结果,关联分析不同耐荫型黑豆根系对弱光胁迫的响应差异。通过逐步回归分析建立了黑豆苗期耐荫性评价数学模型;并通过该模型,筛选出蒸腾速率、株高、叶干重、最大荧光强度和初始荧光强度等5个鉴定指标。在荫蔽条件下测定苗期黑豆的上述5个指标可实现对黑豆苗期耐荫性的综合评价。同时,对23份黑豆种质的耐荫性综合评价值D进行了聚类分析,结果表明,黑豆种质可划分为耐荫型、中度耐荫型和荫蔽敏感型3类。不同耐荫型黑豆种质的根系结构对弱光胁迫的响应程度不同,黑豆的总根长、根表面积、总根体积、根干重等根系强度指标均表现为耐荫型中度耐荫型荫蔽敏感型。这表明耐荫潜力大的黑豆根系更发达。     

Effects of Al stress on the growth and nitrogen uptake of maize varieties with different Al tolerance as related with Al chemical forms on root surfaces

Journal of Soils and Sediments - To examine the effects of Al stress on the growth and nitrogen (N) absorption of maize varieties with different Al tolerance as related with chemical Al forms on...     

钼、硼对大豆氮代谢的影响

研究了3 个大豆品种各生育期不同钼硼水平与大豆氮代谢的关系。结果表明,钼或硼增强大豆根系活力和根瘤生物量,降低大豆叶片硝态氮含量,促进硝酸还原酶活性和全氮含量的提高。在对氮代谢影响的强度上,钼大于硼,且钼和硼有相互促进的作用。大豆3 个品种在对氮代谢的影响上存在着一定的差异。     

Aluminium tolerance mechanisms in Phaseolus vulgaris L.: Citrate synthase activity and TTC reduction are well correlated with citrate secretion

We characterised the physiological mechanisms of tolerance in two bean varieties (Phaseolus vulgaris L. viz. French Bean cv. Amy and Rosecoco (GLP2)) differing in Al tolerance of the varietal level. Root elongation at varying levels of Al over time clearly showed the Al tolerance superiority of Rosecoco over French bean. Aluminium uptake was much higher in French bean, in both root apex and 2 mm region of the root apex. The root cation exchange capacity of the Al-sensitive French bean was markedly higher than that of Rosecoco. Citric acid was the only organic acid whose secretion was stimulated by Al and was higher in Rosecoco than in French bean. The citrate synthase and NADP⁺-isocitrate dehydrogenase activities were apparently higher in Rosecoco than in French bean b1,lt those of phosphoenolpyruvate carboxylase were not significantly different between the two varieties under Al stress. Triphenyl-tetrazolium chloride (TTC) reduction was greater in Rosecoco and was also well correlated with the citrate secretion. These results suggest the role of TTC reduction and citrate secretion as underlying factors in the Al tolerance mechanism of Rosecoco.