Agricultural practice changes with cultivating genetically modified herbicide-tolerant oilseed rape

To facilitate weed suppression, oilseed rape or canola (Brassica napus) has been genetically modified (GM) over the last two decades to incorporate herbicide tolerance (HT). The introduction of oilseed rape in commercial agriculture raises concerns about potential adverse agronomic and environmental effects linked to both the genetic modification and altered agricultural practice. How will this new crop modify the existing cropping practice? What are the potential agro-environmental implications of its introduction? This paper analyses and schematises recorded and conceivable agricultural practice changes with GMHT oilseed rape introduction and its likely agro-environmental effects. It develops a conceptual systematics of influencing factors, subsequent practice changes and likely agro-environmental effects. The results can be used to design the mandatory monitoring of adverse GM crop effects.     

枣树间接地下滴灌根区土壤盐分运移规律研究

通过小区试验研究了间接地下滴灌条件下密植枣树根区不同方向(水平及垂直方向)、不同土层盐分质量比的变化特征,及导水装置直径(50、75、90 mm)和灌水量(9、13、17 L/(棵·次))对枣树根区土壤盐分运移的影响。结果表明:经过一段时间后,垂直方向10~40 cm土层盐分质量比较低,0~10 cm土层盐分质量比最高;水平方向10~50 cm各土层盐分质量比随与出水口水平距离的增加而增大。在单次灌水后导水装置直径一定时各土层脱盐率随灌水量的增加而增大。当灌水量一定时,10~40 cm土层脱盐率随导水装置直径的增加呈减小的趋势,0~10 cm、40~50 cm脱盐率随导水装置直径增大呈低-高-低的趋势。在7—9月份,当导水装置直径为75 mm,灌水量为13、17 L/(棵·次)时,0~50 cm土层土壤平均盐分质量比均较低而且变化幅度较小。综合考虑节水、抑盐效果,确定导水装置直径为75 mm,灌水量为13 L/(棵·次)为适宜的间接地下滴灌灌溉模式。     

硝酸镧处理对短穗鱼尾葵幼苗耐寒性的影响

为探明硝酸镧对短穗鱼尾葵(Caryotamitis)耐寒生理指标的影响,用4个不同浓度的硝酸镧溶液(0、100、350、500mg/L)喷施盆栽短穗鱼尾葵叶片,经变温处理后检测各项耐寒指标。结果表明,超氧化物歧化酶(SOD)、过氧化物酶(POD)、丙二醛(MDA)、脯氨酸、可溶性蛋白和叶绿素的含量表现出明显的浓度效应,而且25℃恢复后幼苗叶片的各项耐寒指标的模糊隶属函数值分别为0.41、0.46、0.70、0.50,其中350mg/L硝酸镧溶液处理对提高短穗鱼尾葵幼苗的耐寒性具有显著的效应。     

Significance of salt transport patterns in rice varieties differing in salt tolerance

Abstract

The absorption mechanisms for Na, K, SO₄ and Cl were tested in a salt tolerant (PVR 1) and a salt sensitive (GEB 24) rice varieties. The salt tolerant variety accumulated significantly larger amounts of Na than the salt sensitive variety. Further, PVR 1 absorbed SO₄ from Na₂SO₄ in preference to that from K₂SO₄. The absorption patterns for K and Cl were similar in both the varieties. It is concluded that the capacity of plant species to accumulate greater amounts of Na is a reflection of their halophytic feature.     

生物炭表面水溶活性分子可以有效提高水稻的耐旱性

生物炭是一种可以改良土壤、增强作物产量和提升作物品质的新型农林废弃物再利用材料。本研究通过振荡方式制备生物炭浸提液,利用水培系统培养水稻幼苗,以20%PEG6000、300 mmol/L和500 mmol/L甘露醇模拟干旱胁迫,研究生物炭表面水溶活性分子对水稻幼苗抗旱性的影响。研究结果发现:生物炭浸提液可有效缓解干旱胁迫造成的水稻种子萌发和幼苗生长抑制,缓解叶绿素含量、鲜重及存活率的降低,同时可以降低体内的活性氧积累等。实时定量RT-PCR检测表明生物炭浸提液促进干旱胁迫响应标志基因的表达量。研究结果说明生物炭浸提液可以提高干旱胁迫下水稻幼苗的抗氧化能力,进一步提高水稻幼苗对干旱胁迫的耐受性。     

DROUGHT STRESS: Soil Water Availability Alters the Inter‐ and Intra‐Cultivar Competition of Three Spring Wheat Cultivars Bred in Different Eras

Competition for water generates a classic aspect of the tragedy of the commons, the ‘race for fish’, where crops must allocate more resource to acquisition of the limiting resource than is optimal for crop yield allocation. A pot experiment using a simple additive (target–neighbour) design was conducted to examine the above‐ground and below‐ground growth of three spring wheat (Triticum aestivum L.) cultivars when grown alone and in mixtures at three levels of water availability. The effects of competition and water availability were compared by observing patterns of growth, biomass allocation and below‐ground outcomes. Competitive interactions were investigated among cultivars ‘HST’, ‘GY602’ and ‘LC8275’, target plant of each cultivar grown without neighbouring plants are referred to herein as control plant and one target plant of each cultivar sown surrounded either by same or another cultivar as intra‐ or inter‐cultivar competition. Competitive ability was assessed as the response ratio (lnRR) between the target plant surrounded by six other plants and the target plant in isolation. Our results showed that the cultivar ‘HST’, released over a century ago, produced a higher biomass and grain yield than the more recently released cultivars ‘LC8275’ and ‘GY602’ when grown as isolated plants with sufficient water supply. However, competition for resources from neighbours led to target plant biomass and grain yield being significantly reduced relative to controls in all three cultivars, particularly in ‘HST’. When subjected to intra‐cultivar competition, the two recently released cultivars ‘LC8275’ and ‘GY602’ had higher grain yields and water use efficiency for grain than ‘HST’ in all three water regimes. The landrace ‘HST’ had better and significantly linear relationships between biomass and biomass allocation, root length and specific root length, whereas the recent and modern cultivars had much more water‐related species‐specific changes in root morphology and allocation patterns. These results suggest that crop traits that influence competitive ability, such as biomass allocation to roots and root plasticity in response to drought have changed in modern wheat cultivars because of breeding and selection.     

新牧一号苜蓿MvP5CS基因的克隆和功能分析

为研究苜蓿（Medicago sativa）耐盐分子机制，为抗逆分子育种提供依据，通过同源克隆和RT PCR技术克隆了新牧一号杂花苜蓿（M.varia Xinmu 1）的MvP5CS基因， MvP5CS全长2 148 bp，Genbank登录号为：EU371644。荧光定量PCR分析发现，在盐胁迫下MvP5CS基因表达明显上调，说明 MvP5CS与苜蓿的耐盐性相关。利用农杆菌介导的叶盘转化法，将MvP5CS基因成功转入烟草（Nicotiana tabacum），盐胁迫下转MvP5CS基因T1代烟草萌发率和根长均高于非转基因烟草。表明新牧一号苜蓿P5CS基因能够提高转基因烟草的耐盐性。     

大豆高赖氨酸基因PM8在烟草中的超量表达及其抗非生物胁迫功能研究

应用生物信息学方法在GenBank数据库查找到1条编码大豆LEA3蛋白的高赖氨酸蛋白基因PM8(登录号:Z22872),并利用RT-PCR方法从大豆干种子中克隆得到该基因,序列分析表明,PM8基因与GenBank上的序列存在5个碱基的差异,使编码蛋白的赖氨酸重量比由原来的19.65%增加为19.93%。构建了PM8基因的植物表达载体pEMT-PM8,用农杆菌介导法转化烟草。从转PM8基因的PCR阳性植株中选取5个既抗盐又抗旱的株系进行Real-timePCR检测。结果表明,PM8基因全部超量表达。研究为培育高营养品质且抗逆的转基因作物研究提供了一条新的途径,具有重要的研究价值。     

盐藻DNA对水稻幼苗在低盐中生长的影响

[目的]分析盐藻DNA对水稻幼苗在低盐中生长的影响。[方法]将刚萌发的水稻幼苗根系浸入5 mg/L盐藻DNA溶液中培养2d,以蒸馏水培养为对照,处理后的水稻幼苗栽于含有氯化钠3 g/L的MS培养液中培养,分析盐藻DNA对水稻幼苗在低盐中生长的影响。[结果]水稻幼苗用5 mg/L盐藻DNA处理后,在含氯化钠3 g/L的MS培养液中培养15 d,其平均株重为150.7 mg,比对照增加了10.3%;平均株高为15.28 cm,比对照增加了6.1%;平均存活率为45.0%,比对照增加了125.0%;平均根数为7.15条,比对照减少了2.8%;平均根长为3.83 cm,比对照缩短了8.4%。说明盐藻DNA提高了水稻幼苗的耐盐适应性。[结论]盐藻DNA可提高水稻的耐盐适应性。