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…     

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。     

关于氮有效性影响细根生产量和周转率的四个假说

在全球变化如氮沉降及温度升高等可能导致土壤氮有效性增加的背景下,细根动态如何变化一直是陆地生态学研究中的一个重要内容.本文综述了前人提出的细根动态响应土壤N有效性提高的4个代表性假说:1)细根生产量和周转率都提高;2)细根生产量和周转率都下降;3)细根生产量下降,周转率提高;4)细根生产量提高,周转率下降.根据2000年以来以微根管方法为主测得的根系动态数据,笔者认为假说1)和假说2)得到的支持最为充分.此外,还探讨了树种、细根异质性、菌根真菌、细根采样方法和施肥方法等对上述各假说检验的影响.     

不同播期对不同基因型油菜产量特性的影响

研究了 3个不同基因型油菜品种的产量与产量构成因素的特征及其与光温条件的生态关系 ,探讨了长江中游油菜区多熟种植条件下提高油菜单产的可行途径 .结果表明 ,因播种期不同而导致油菜生育期间光温条件的不同 ,使各播期产量及产量构成因素产生了较大的差异 .油菜单株角果数、角果皮指数、主茎产量、分枝产量均与积温和日照时数呈极显著正相关 ,而千粒重和SNPA与之无关 .播种期对油菜产量的影响主要是通过影响分枝产生及其产量形成而实现的 .因此多熟制油菜的播种期可适当提早 ,10月 2 0日以后播种的油菜 ,其种植密度可增加至 3 75× 10 5～ 4 5× 10 5株·hm-2 ,以主茎弥补分枝小而少的不足 ,实现油菜单产的提高 .     

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;而幼苗叶片和花纲内ＲＮａｓｅ活性产强,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,植物体内核酸分解和加剧是核酸含量下降的一个重要原因。     

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。     

不同硼浓度对棉花磷的吸收和分配的影响（简报）

在缺硼和高硼条件下,棉花的Ｉｍａｘ明显降低,Ｐｉ的吸收受抑,高硼大于缺硼,磷由根向地上部的运输也有受抑的趋势,０、５．４、１０８ｍｍｏｌ／Ｌ的硼对棉花吸收的Ｐｉ的Ｋｍ值匀无明显,说明Ｈ３ＢＯ３与Ｈ２ＰＯ４＾－和ＨＰＯ４＾＝不存在竞争性抑制。     

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。     

Formulations of Bacillus subtilis BY-2 suppress Sclerotinia sclerotiorum on oilseed rape in the field

We are developing a collection of Bacillus strains, isolated from different environments, for use in controlling Sclerotinia sclerotiorum on oilseed rape in China and elsewhere. Strain BY-2, isolated from internal tissues of an oilseed rape root, was demonstrated to be Bacillus subtilis based on biochemical and morphological characteristics and on 16S RNA gene sequence. Photographic evidence from gnotobiotic studies using the lacZ-tagged strain BY-2(pUC18) confirmed that this strain was capable of colonizing internal root tissues. Strain BY-2 did not effectively colonize the ectorhizosphere or the surface of the stems or leaves of oilseed rape when applied in pellet or wrap seed treatment formulations. Populations of BY-2 dropped from 10⁸ CFU seed⁻¹ to 10⁴ CFU g root⁻¹ and ⩽10² CFU g stem⁻¹ or leaf⁻¹ after 60 days. Strain BY-2 was applied as a pellet seed treatment formulation alone, as a spray at flowering alone, and as the pellet seed treatment formulation combined with the spray application in two field trials at the Wuxue location conducted in two consecutive years. These three treatments containing BY-2 provided disease control (disease incidence) and mean seed yield that was similar to the chemical control treatment and significantly greater than the pellet without bacteria and non-treated control treatments. All three of these BY-2 treatments were similar to each other with regard to these two metrics and to treatments containing B. subtilis Tu-100, a genetically distinct strain previously shown to be effective against this disease. In two additional field trials, conducted in consecutive years at the Wuhan location, strain BY-2 applied as a wrap seed treatment formulation alone, as a spray at flowering alone, and as the wrap seed treatment combined with the spray application provided disease control (disease incidence) and mean seed yield that was similar to the chemical control treatment. These three BY-2 treatments also were significantly greater than the non-treated control treatments and compared favorably to treatments containing Tu-100. There was no evidence of BY-2 promoting growth of oilseed rape when applied in the pellet or wrap seed treatment formulations in field trials conducted at the Wuxue or at the Wuhan locations. We now have three Bacillus strains (B. subtilis strains BY-2 and Tu-100, B. megaterium A6) that control S. sclerotiorum on oilseed rape in the field that can be tested in strain combinations for enhanced disease control. We also have multiple methods for application of Bacillus strains as both seed treatment and foliar applications were effective.     

Comparative assessment of the sensitivity of oilseed rape and wheat to limited water supply

The drought‐sensitivity of oilseed rape (OSR, Brassica napus cv. SW Landmark) was investigated, using the more widely studied crop species wheat (Triticum aestivum cv. Tybalt) as a benchmark. The water relations of OSR and wheat were compared in lysimeter and controlled environment experiments to test the hypothesis that the growth of OSR is restricted to a greater extent by soil drying than wheat and to determine whether the greater sensitivity results from differences in root or shoot traits. Plants were grown, with or without irrigation, in 1.2 m tall lysimeters packed with a sandy clay loam soil. The experiment was conducted in an open‐sided glasshouse to encourage air flow and to resemble a field environment as far as possible; plant population densities were equivalent to commercial crops. Irrigated OSR (evapo)transpired more water than wheat (498 vs. 355 mm), but had a comparable water use efficiency (WUE; 4.1 vs. 4.4 g DW mm^?1 H₂O). Oilseed rape showed a greater reduction in above‐ground growth (52% vs. 21%) and a smaller increase in WUE (27% vs. 45%) when water was withheld. Oilseed rape also responded to soil drying at a lower soil moisture deficit than wheat; transpiration rates fell below the potential of irrigated plants when plant available water remaining in the soil profile declined from 54 to 23% compared to 38 to 9% for wheat. The root hydraulic conductivity of young OSR plants, measured on root surface area basis, was about twice that of wheat, and was comparable on a root length basis. The results show that OSR was more sensitive to a restricted water supply than the benchmark species wheat and that the greater sensitivity resulted from differences in shoot, rather than root, characteristics. The root system of OSR was at least as efficient as wheat at extracting water from soil.     

Growth and NPK uptake of high-yielding cotton grown at different nitrogen levels in a permanent-plot experiment

Growth and N, P, K uptake of Acala SJ-2 cotton (Gossypium hirsutum) were investigated in an irrigated permanent-plot field (Typic chromoxerert) at Bet Dagan, Israel, under semi-arid conditions using different nitrogen levels: 0, 60, 120, 180 and 240 kg N ha⁻¹. The total dry matter accumulation at these levels was 9.0, 10.7, 15.1, 17.1 and 15.6 ton ha⁻¹, respectively. The uptake of N, P and K was 110, 144, 267, 322 and 301 kg N ha⁻¹∶31, 34, 46, 44 and 38 kg P ha⁻¹; and 120, 151, 208, 251 and 230 kg K ha⁻¹, respectively. Dry matter production, as well as N, P, K uptake by the cotton plants were greatly increased by raising the N application levels to 120 or 180 kg N ha⁻¹, but the pattern of accumulation and relative distribution of dry matter and NPK among plant organs were not considerably affected. Joint contribution from the Dept. of Soil Chemistry and Plant Nutrition, ARO, the Volcani Center, Bet Dagan, Israel (No. 1413-E, 1985 series)     

Differential response of oilseed rape (Brassica napus L.) cultivars to low boron supply

Three experiments were carried out on an alluvial sandy loam (Udifluvent) at Tonglu, Zhejiang Province, P.R. China from 1992 to 1995, to determine the genotypic range in boron (B) efficiency of 16 oilseed rape (Brassica napus L.) cultivars, to identify the B-efficient cultivars and to identify specific responses which can be utilised for selection in a breeding program. The 16 cultivars which included high-quality and conventional types differed significantly in survival, plant height, leaf area, shoot dry weight and seed yield; however, the ranking of the cultivars for their seed yield or other plant traits differed with B treatment. With severe B deficiency (CaCl2 extractable B < 0.26 mg/kg) and no boron applied, none of the cultivars exhibited significant B efficiency, with seed yield <300 kg/ha. With moderate B deficiency (CaCl2 extractable B 0.34 mg/kg or 0.17 kg B/ha applied), seed yield varied significantly among the cultivars from 397 to 1889 kg/ha in year 1 and from 616 to 1260 kg/ha in year 3. Zhongyou 821 and 92-13 were the most B-efficient and Wanyou 324, Huashuang 2 and Su 2051 were the most B-inefficient cultivars under moderate B deficiency. Significant differences were found among the cultivars in leaf B concentration; however, there was no close relationship between leaf B concentration and seed yield responses to B of oilseed cultivars. Of all the growth parameters measured, leaf area was the early indicator best correlated with subsequent seed yield and may be useful for evaluating the response of cultivars to low B supply. Contrary to current opinion, it was also found that high-quality oilseed rape cultivars were not all sensitive to low B supply nor were all conventional cultivars B-efficient.     

镧对烟草愈伤组织和油菜幼根钙含量的影响

ＭＳ培养基中添加镧（Ｌａ）（０ ．０１ ～０ ．１０ｍ ｍｏｌ·Ｌ－ １） 培养烟草愈伤组织,其总Ｃａ２ ＋ 及原生质体Ｃａ２ ＋ 含量明显比对照（ 不加Ｌａ） 低;长时间（ 继代培养３０ｄ） 较短时间培养（ 悬浮培养２４ｈ） 低．低浓度（０ ．０１ ～０ ．０５１ｍｏｌ·Ｌ－ １）Ｌａ３ ＋ 使细胞壁中Ｃａ２ ＋ 含量高于对照并随浓度提高而增加,高浓度（０ ．１０１ｍｏｌ·Ｌ－ １） 则减少．与Ｃｅ２ ＋ 相比较,Ｌａ３ ＋ 的排Ｃａ２ ＋ 作用稍弱于Ｃｅ３ ＋ ．以不同浓度Ｌａ（ＮＯ３）３ 溶液浸种,油菜幼根总Ｃａ２ ＋ 及原生质体中Ｃａ２ ＋ 含量变化与上述类似．Ｌａ３ ＋ 使烟草愈伤组织褐化明显,生长量比对照低．     

Root growth,macro-nutrient uptake dynamics and soil fertility requirements of a high-yielding winter oilseed rape crop

Shoot growth, root growth and macro-nutrient uptake by a high-yielding (5t/ha grain) winter oilseed rape crop have been measured. Maximum rooting density in the top 20cm of soil was 9.4 cm cm⁻³ and roots reached a depth of at least 1.8 m. Maximum nutrient uptakes were 364 kg ha⁻¹ for N, 43 kg ha⁻¹ for P, 308 kg ha⁻¹ for K, 287 kg ha⁻¹ for Ca and 16 kg ha⁻¹ for Mg. A 30-day drought coincided with the flowering period and root and shoot growth, as well as nutrient uptake rates, were reduced. Nutrient concentrations in the soil solution necessary to sustain the nutrient fluxes into the root system by diffusive supply have been calculated. Peak values were in the range 10 μM for P to 87 μM for N, lower than the observed concentrations, and it was concluded that nutrient transport to roots was not a limitation to uptake by this rape crop.     

土壤水分和供硼状况对不同硼效率油菜苗期生长、水分含量和硼形态的影响

通过土培试验,研究了土壤水分和供硼状况对不同硼效率油菜苗期生长、叶片水分含量和硼形态的影响.结果表明:低水分胁迫条件下,硼高效甘蓝品种和硼低效甘蓝品种在高供硼水平下的单株鲜质量比低供硼水平分别增加了43.1%和31.7%,但品种间没有显著差异;硼高效品种在两种供硼水平下的束缚态水分含量分别比低效品种高11.4%和1.7%,半束缚态硼分配比例分别比低效品种高6.9%和23.8%.正常水分条件下,硼高效甘蓝品种和硼低效甘蓝品种在高供硼水平下的单株鲜质量比低供硼水平分别增加了11.1%和27.4%;硼高效品种在两种供硼水平下的自由态水分含量较硼低效品种多,自由态硼累积量为低效品种的2倍多,这有利于硼在高效植物体内的移动运输.     

硼、镉元素及其交互作用与油菜产量和品质

硼和镉两种元素是影响油菜产量和品质的两个重要因素.硼是植物生长所必需的微量元素,施硼是油菜种植的必需环节;镉是植物生长的非必要元素,易在油菜体内富集,可能通过食物链危害人体健康.本文主要从镉含量与油菜食品安全品质角度考虑,阐述了油菜对镉的积累和耐受机制;同时,概括了前人总结的硼对油菜的产量和品质的影响.最后,结合本人研究区广西地区土壤有效硼含量低,全镉含量高的现状,提出运用硼镉交互作用机理,通过施加适量硼肥,提高油菜的产量和品质,消除土壤镉的潜在危害,从本质上改善该地区土壤存在的低硼高镉现状.     

Effect of soil-applied NPK fertilizers on severity of black spot disease (Alternaria brassicae) and yield of oilseed rape

Effect of soil application of eight combinations of NPK fertilizers on the severity of black spot disease (BSD), caused by Alternaria brassicae (Sacc.) Berk., and yield of short duration oilseed rape (Brassica campestris L) were investigated under both pot and field conditions in 1987–88, 1988–89 and 1990–91. The severity of BSD was significantly greater (36–48%) on plants grown in ground treated with NP (N 90 kg ha^–1+P 40 kg ha^–1) applied as urea and single superphosphate respectively than on plants from the unfertilized control (NoPoKo) (o). However, the severity of BSD was significantly smaller (25–33%) when K (40 kg ha^–1) was applied as muriate of potash than in plants from control and NP treatments. The effect of NK (N 90 kg ha^–1+K 40 kg ha^–1) in decreasing the severity of BSD was increasingly more pronounced than the effects of PK (P 40 kg ha^–1+K 40 kg ha^–1), NP and K (40 kg ha^–1) applications. The decrease in the severity of BSD due to K was due to increased production in plants of phenolics which inhibited conidial germination and decreased sporulation of A. brassicae.The decrease in the severity of BSD due to NK application gave consistently increased seed yield 68% more than those of control and other treatments. The K-fertilized plants also showed increased resistance to lodging, increased 1000-seed weight and decreased seed infection. Seeds obtained from K-fertilized plants showed good seed germinability and vigorous seeding growth.