镉与磷、锌、铁、钙等元素的交互作用及其生态学效应

镉是动物和植物的非必需元素 ,也是毒性最大的重金属之一。环境镉污染对植物、动物和人体均产生毒害作用。镉与许多生命必需营养元素存在着交互影响关系 ,相互影响着对方的功能发挥。镉污染胁迫可影响动植物和人体对营养元素的吸收 ,相反补充营养元素可减轻镉的毒害。但是 ,由于每个元素的性质和功能不一样 ,因此不同元素与镉的交互作用存在着差异性。镉与营养元素的交互作用研究可为生物镉污染防治提供科学依据。     

不同土壤水分状况下施硼对油菜硼吸收、利用的影响

1　引　　言我国是油菜生产大国 ,也是一个土壤缺Ｂ面积较大的国家 .由于油菜缺Ｂ问题突出 ,施用Ｂ肥已成为提高油菜产量、改善品质的重要措施[2 ,3 ,11] .但是 ,Ｂ肥的施用不但存在成本高、难度大、效率低的问题 ,而且也存在造成环境污染的可能性[9] .研究表明[8,10 ] ,不同油菜品种对缺Ｂ的反应存在基因型差异 ,因此 ,筛选、培育Ｂ营养高效基因型油菜以适应缺Ｂ土壤环境是解决油菜缺Ｂ问题的最有效途径之一 .植物对土壤中Ｂ的吸收、运输及利用因土壤水分状况而异[4 ,5] .研究不同水分条件下尤其是干旱情况下Ｂ素营养对油菜Ｂ营养效率的影…     

不同硼效率甘蓝型油菜品种细胞壁中硼的分配

应用不同硼效率甘蓝型油菜品种 ,研究硼在细胞壁中的分配。硼主要结合在细胞壁中 ,缺硼显著提高硼在细胞壁中的分配比例。根系细胞壁硼含量显著低于叶片 ,但根系细胞壁硼占根系总硼量之比例显著高于叶片。同一品种根系及其细胞壁、老叶细胞壁硼含量受生育期影响较小 ,新叶及其细胞壁、老叶硼含量受生育期影响较大。在正常供硼条件下 ,硼高效品种根系细胞壁和叶片细胞壁硼含量均低于低效品种 ;正常和缺硼条件下 ,硼高效品种细胞壁硼占器官总硼量之比例均低于低效品种。说明硼低效品种需较多的硼构建细胞壁。     

氮磷钾、硼水平对不同基因型油菜硼吸收及某些生物学性状的影响

采用温室土培试验,研究了不同氮磷钾复合型（NPK肥）施用水平下,油菜对B的吸收及其耐缺B机理以及缺B对某些生物学性状的影响,结果表明,缺B时,随NPK肥施用量的增加,油菜植株缺B症状加重,苗期叶面积及其生长速率减小,叶绿素含量增加,硝酸还原酶活性下降,成熟期单株有效分枝,有效角果数减少,籽粒产量降低,可以认为,油菜大苗期最新展开叶（YOL）与最新成熟叶（YML）的B浓度比值可作为不同基因型油菜植株体内B移动性大小的判氟指标,B移动性及B利用率的大小是不同基因型油菜耐缺B的重要营养机理之一。     

油菜幼苗对硼的吸收与运转及钙的影响

硼促进油菜幼苗生长和对N、P、K、Ca 营养元素的吸收.当油菜生长介质中钙浓度增大时,植株吸硼量和硼在新叶中的积累减少,老叶中积累增加。硼在油菜体内的运转系数在低硼条件下较大,并随钙处理水平的增加而下降.结果表明,在硼素供应有限的条件下,油菜体内硼仍具一定的移动性,钙则使硼的吸收和移动性下降.     

油菜幼苗对硼的吸收与运转及钙的影响

硼促进油莱幼苗生长和对N、P、K、Ca营养元素的吸收。当油莱生长介质中钙浓度增大时,植株吸硼量和硼在新叶中的积累减少,老叶中积累增加。硼在油莱体内的运转系数在低硼条件下较大,并随钙处理水平的增加而下降。结果表明,在硼素供应有限的条件下,油菜体内硼仍具-定的移动性,钙则使硼的吸收和移动性下降。     

钙、硼对花生生长、产量和品质的影响

在土壤代换性钙和有效硼含量分别为0.84me/100g和0.163mg/kg的条件下,研究了施钙、施硼及钙、硼配施对花生生长、产量和品质的影响。结果表明,施用钙肥能提高花生的产量和品质;施用硼肥能改善品质,但在产量上却产生负效应;钙、硼配施也能提高产量,但主效应仍然是钙。施用钙硼肥料不但使花生成熟期植株中钙、硼含量提高,而且种植花生后土壤中的钙、硼残留量也明显增加。     

镉处理对油菜生长和抗氧化酶系统的影响

通过盆栽实验研究了Cd处理对油菜生长和抗氧化酶系统的影响.结果表明,油菜整株鲜重、叶鲜重随Cd胁迫呈显著降低趋势.逐步回归表明,叶鲜重下降导致油菜整株鲜重下降.油菜叶细胞膜渗透性和MDA随Cd胁迫增大而增加.Cd处理浓度为20 mg·kg^-1时,叶细胞膜渗透性和MDA分别增加29.68％和15.19％,叶细胞膜渗透性和 MDA呈显著正相关,相关系数为0.823^*.Cd处理浓度为5 mg·kg^-1时,叶绿素a、b和a+b含量达到峰值,分别比对照高23.97%、33.63%和26.45%;Cd胁迫对类胡萝卜素含量无显著影响.几种色素对Cd敏感顺序为：叶绿素b>叶绿素a>叶绿素a+b>类胡萝卜素;3种抗氧化酶对Cd敏感顺序为：POD>CAT>SOD.各生理指标IC50表明,油菜只适宜种植在Cd含量小于5 mg·kg^-1的土壤中.     

甘蓝型油菜扩展蛋白家族的全基因组鉴定及其对缺硼胁迫响应的差异分析

以甘蓝型油菜(Brassica napus L.)硼高效品种‘青油10号’和硼低效品种‘Westar 10’为研究对象,采用生物信息学分析、转录组测序和实时荧光定量PCR技术,鉴定其基因组中扩展蛋白的家族成员,并对该基因家族响应缺硼胁迫的表达差异进行分析。结果显示,甘蓝型油菜基因组中包含109个扩展蛋白,可分为4个亚家族,包括:79个扩展蛋白A(BnaEXPAs)、21个扩展蛋白B(BnaEXPBs)、5个类扩展蛋白A(BnaEXLAs)和4个类扩展蛋白B(BnaEXLBs)。同一亚家族中的扩展蛋白具有相对保守的基因结构和蛋白质基序组成。这些扩展蛋白基因分布在19条染色体上,其中10个位于硼高效QTL区间内。转录组测序分析结果表明,缺硼胁迫时‘青油10号’的根、幼叶和老叶中分别有40、18和30个扩展蛋白基因显著上调或下调表达;而‘Westar10’中分别有27、24和41个扩展蛋白基因显著上调或下调表达。其中‘青油10号’根中的BnaC04.EXPA6a,幼叶中的BnaA09.EXPA5以及老叶中的BnaA09.EXPA16、BnaC04.EXPA3、BnaCnn.EXPA5b和BnaA03.EXPA8基因的表达水平均显著高于‘Westar10’。研究结果说明甘蓝型油菜基因组中扩展蛋白基因家族数量庞大,其中高、低效品种间和不同硼水平中差异表达的扩展蛋白可能在甘蓝型油菜低硼适应性中发挥重要作用。     

硼对油菜体内核酸代谢的影响

硼胁迫造成油菜植株生长异常,使幼苗干物重显著下降;而幼苗叶片和花药内ＲＮａｓｅ活性明显增强,ＲＮＡ的分解加剧,ＲＮＡ和ＤＮＡ含量均下降,引起蛋白质的合成受阻,可溶性蛋白质含量急剧减少。这说明缺硼或硼过量时,植物体内核酸分解加剧是核酸含量下降的一个重要原因。     

The effects of a paclobutrazol-based growth regulator on the yield, quality and ease of management of oilseed rape

A mixture of paclobutrazol and chlormequat chloride plant growth regulators (JF10405, Parlay C) was tested on field crops of two ‘double zero’ oilseed rape cultivars in two seasons. Application rate and timing of JF10405 were varied. Very large plots enabled the use of commercial farm equipment to treat and harvest the experiments. Untreated plots showed considerable lodging at harvest in all experiments. Treatment with JF10405 had only small effects on the height of mature plants but, generally, reduced lodging substantially even at the lowest rate tested. All JF10405 treatments increased seed yields, several significantly so, particularly a 2.50 litre/ha rate, although the optimum timing varied between experiments. Seed oil contents were little affected, but levels of glucosinolates were significantly decreased in some instances. Treatments giving good control of lodging also took less time to harvest, especially when cutting against the direction of the lodging. The results-are discussed in relation to the means by which these improvements in seed yield and quality were achieved, and crop management facilitated.     

The effects of lodging and a paclobutrazol — chlormequat chloride mixture on the yield and quality of oilseed rape

The effects of lodging and a plant growth regulator mixture on oilseed rape cv. Ariana were studied in three field experiments. Natural and artificially induced lodging treatments varying in time of imposition and severity were compared to a supported control. A mixture of paclobutrazol and chlormequat chloride was applied either as a spray or as paclobutrazol granules followed immediately by a chlormequat chloride spray.
In 1987, severe lodging treatments reduced yield by up to 52%. Yield penalties varied with the time at which lodging was imposed. Yield was inversely correlated with the ground cover of volunteers growing from shed seed under lodged crops.
In 1988, two experiments showed increased incidence of disease and decreases in seed yield and quality in lodged crops. Yield reductions were related to the severity of lodging. Lodging decreased oil contents and increased glucosinolate levels. PGR treatments reduced lodging and maintained yield at a level not significantly different to a supported control treatment. Oil contents were also similar in seed from PGR treated and control plots. Glucosinolate levels in PGR treated seed were similar to control levels in one experiment and intermediate to those from control and artificially lodged plots in another experiment.
The results are discussed in relation to the use of PGRs to prevent lodging in 'double zero' varieties of oilseed rape, and the potential losses from using ground vehicles to apply pesticides after flowering.     

Influence of lodging and nitrogen rate on the yield and yield attributes of oilseed rape (Brassica napus L.)

The effects of lodging and nitrogen rate were studied in a field trial of oilseed rapeBrassica napus L. Lodging decreased seed yield (16%) compared with a frame-raised crop. Yield decreased because of a significant reduction in each of the yield components coupled with a reduced plant population caused by stem breakage at the ground level. Lodging also reduced the final crop dry weight and harvest index. Seed yield was also lower when 200 kg ha^–1 nitrogen was applied than with 400 kg ha^–1. A general decrease in pod number m^–2, seed nuber pod^–1 and seed weight caused the lower yields. The use of 400 kg ha^–1 of nitrogen changed the contribution of the terminal raceme and individual branches with respect to seed yield. Seed nitrogn content and nitrogen yield increased at the 400 kg ha^–1, lowering both seed oil content and oil yield.     

Sulphur application improves the growth, seed yield and oil quality of canola

Sulphur (S) nutrition is very important for harvesting potential seed and oil yield of rapeseed. This study evaluated response of foliage applied thiourea on the performance of two canola cultivars Shiralee and Dunkeld. Sulphur was applied to soil (40 kg ha^?1) or foliage (500 and 1,000 mg L^?1) at rosette, bud initiation and flowering stages using elemental S or thiourea as source, respectively; no S application was taken as control. Among all the treatments, soil application of S improved the crop growth, yield and oil quality in both cultivars and was followed by foliar application of thiourea at 1,000 mg L^?1 compared with no application. Soil applied S and foliar thiourea (1,000 mg L^?1) delayed the flowering and maturity. Soil and foliar applied S significantly improved leaf area index, crop growth rate, net assimilation rate and chlorophyll contents. Plant height, number of branches, siliqua per plant, seed number per siliqua, 1,000-seed weight, biological and seed yield were also increased by soil applied S and foliage applied thiourea (1,000 mg L^?1). Nonetheless, improvement in harvest index, seed oil, protein and glucosinolate contents was only observed from foliage applied thiourea (1,000 mg L^?1). Response of cv. Shiralee to sulphur application was better than cv. Dunkeld. In conclusion, foliar applied thiourea (1,000 mg L^?1) can have potential to improve growth, yield and oil quality in canola and can be economically viable and attractive alternative source.     

Foliar spray of brassinosteroid enhances yield and quality of Solanum lycopersicum under cadmium stress

The presence of cadmium in the soil above a particular level is proposed to check not only plant growth but also productivity and fruit quality. Therefore, in the present study investigations are directed to evaluate the effect of four levels of cadmium (3, 6, 9, 12 mg kg⁻¹) in interaction with two analogs of brassinosteroids on the growth, fruit yield and quality of tomato. Under greenhouse conditions plants were analyzed for antioxidant system activity and photosynthetic assimilation efficiency. Cd stressed plants exhibited poor growth and biological yield. The metal also had a negative impact on the antioxidant system of the resulting fruits. However, the follow up application of BRs (10⁻⁸ M) neutralized the damaging effects of the metal on the plants.     

模拟酸雨对油菜(Brassica napus L.)生长、产量及品质的影响

以油菜为供试材料,通过田间试验方法研究了酸雨对农作物生长、产量及品质的胁迫效应.研究结果表明,模拟酸雨胁迫对油菜的生长发育有较大的影响,具体表现为株高、叶面积生长受抑,叶单面鲜重明显降低,且在pH3.1时开始出现外观上的可见伤害;产量的分析结果表明,pH4.1可作为酸雨对油菜产量的影响阈限;品质特征指标分析结果表明,酸雨胁迫会导致油菜粗脂肪含量降低,使可溶性糖含量减少,而且随着酸度增强,粗脂肪与可溶性糖降低幅度越大;酸雨胁迫对可溶性蛋白质的影响阈限在pH5.1与pH4.1之间,对游离氨基酸总量的影响阈限在pH4.1与pH3.1之间,而对还原性糖、总酸度的影响阈限则在pH3.1与pHl.5之间,但以上各指标的确切阈值及酸雨对其影响的具体机理还有待进一步研究.     

Injury to oilseed rape caused by mirid bugs (Lygus) (Heteroptera: Miridae) and its effect on seed production

Injury by Lygus spp. to oilseed rape, Brassica napus L. and Brassica campestris L., was assessed based on laboratory and field studies in Alberta, Canada. The visible injuries consisted of lesions on the surfaces of stems, buds, flowers and pods similar to those described for other crops. They caused buds and flowers to abscise and seeds to collapse, and reduced the weight of healthy seeds produced per pod. The plants compensated for bud loss so that no net reduction in the number of pods occurred. However, in some situations the damage to buds resulted in a reduced seed yield that increased with the amount of injury. The plants also compensated for flower loss so that no net reduction in the number of pods occurred, but seed yield declined as injury increased. Plants did not compensate for seeds that collapsed as a result of lygus feeding. The feeding activity of lygus bugs reduced seed yield in oilseed rape.     

Effects of boron on growing pullets

The effects of dietary boron on bone ash content and on the ultimate shear force, stress, and fracture energy of the tibia, femur, humerus, and radius from white Leghorn pullets were investigated. There was a significant increase in the shear force of the tibia and femur for pullets supplemented with 50 and 100 mg/kg of dietary boron. There was a significant increase in the shear stress of the tibia at 50 and 100 mg/kg of boron, and also an increase in shear fracture energy at 50 and 100 mg/kg boron for the femur. Tibia bone ash content increased significantly at 50, 100, and 200 mg/kg boron with the highest value at 50 mg/kg. Even though there was not a significant increase in body wt at 50 and 100 mg/kg boron, the pullets fed these supplements were consistently heavier than the control group.