Boron and zinc deficiencies and toxicities and their interactions with other nutrients in soybean roots,leaves, and seeds

In many parts of the world, soils deficient and/or toxic in micronutrients reduce potential soybean (Glycine max) yields. The objective of our study was to grow plants in low to high concentrations of boron (B) and zinc (Zn) to determine how B and Zn deficiencies and toxicities affect soybean growth and interact with other essential nutrients in roots, leaves, and seeds. We found that B significantly affected levels of all essential nutrients except manganese and iron, while Zn significantly affected all essential nutrients in at least one plant tissue tested. Some of the physiological responses and nutrient interactions were cultivar-dependent. This study showed how deficiencies and toxicities of B and Zn affect plant growth and how B and Zn fertility interacts with many of the other essential nutrients.     

外源H2S对盐胁迫下红砂幼苗叶片和根系氮代谢的影响

H₂S作为新型气体信号分子在调控植物生长发育和抗逆境胁迫中发挥着重要作用。为探究外源H₂S对盐胁迫下红砂(Reaumuria soongorica)氮代谢的影响机制及最佳叶施浓度,以当年生红砂幼苗为材料,采用盆栽试验,以1/2 Hoagland浇灌为对照(CK)考察在300 mmol·L^-1NaCl胁迫(CK300)下,叶面喷施不同浓度(0、0.010、0.025、0.050、0.100、0.250、0.500、1 mmol·L^-1)H₂S供体硫氢化钠(NaHS)对红砂叶片和根系中硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性以及硝态氮、可溶性蛋白和游离氨基酸含量的影响。结果表明,盐胁迫下,红砂幼苗根、叶中可溶性蛋白、游离氨基酸、硝态氮含量以及NR、GOGAT、GS活性均较对照(CK)显著下降。经不同浓度外源H₂S处理后,红砂根、叶中可溶性蛋白含量与单独盐胁迫对照(CK300)相比显著降低,NR、GOGAT、GS活性和硝态氮、游...     

Influence of soil temperature and moisture on micronutrient supply,plant uptake,and biomass yield of wheat,pea, and canola

Abstract

Crop yield response to micronutrient fertilization is difficult to predict, particularly under unfavorable environmental conditions as these may alter both crop nutrient demand and the soil micronutrient supply to plant roots. The research objective was to evaluate the effect of various soil temperature and moisture conditions on crop growth response to added micronutrient copper (Cu), zinc (Zn), and boron (B) along with soil micronutrient supply and distribution among fractions. Brown and Dark Brown farm soils collected from southern Saskatchewan were used to grown wheat, pea and canola within controlled environment chambers. The biomass yields of all crops decreased under cold soil temperature and moisture stress (drought and saturated) conditions. Greater plant uptake of Cu, Zn, and B was associated with optimum (i.e., field capacity) soil moisture and warm temperature (23°C) growing conditions, compared to drought (i.e., 50% field capacity), saturated, and cold (5°C) temperature conditions. Environmental stress had the greatest impact on pea growth, reducing crop yield and micronutrient utilization efficiency more than 95%. Soil supplies of Cu and Zn were most negatively impacted by drought stress due to reduced mobility of these diffusion limited nutrients. The extractable micronutrients levels and chemical speciation fractions of Cu, Zn, and B indicating that bioavailability and micronutrient transformation were not affected during our short-term (i.e., six-weeks) study. However, it is suggested that assessments of micronutrient forms also be conducted on soil samples under actual moisture and temperature conditions as they exist in the experiment, as well as on dried, processed samples.     

不同钾水平对苗期玉米铬的吸收和生理特性的影响

采用溶液培养的方法,研究了不同钾素水平对苗期玉米地上、地下部铬的吸收、转运及其生理特性的影响。结果显示,在六价铬作用下,玉米幼苗的各项生理指标均受到一定的影响,生物量随着铬浓度的升高而呈现降低趋势。在铬浓度0-100μmol.L^-1之间,植株地上、地下部六价铬的含量随外界铬处理浓度的增加而增加,在100μmol.L^-1时,铬含量达到最大;叶绿素含量、根系活力随六价铬浓度的增加而降低,在100μmol.L^-1时,叶绿素、根系活力最小;丙二醛（MDA）含量呈先降低后上升趋势,在40μmol.L^-1时,丙二醛含量最小。钾素可缓解重金属铬对玉米幼苗的毒害作用,在400-1 600μmol.L^-1之间,不同钾水平处理均可显著减少玉米幼苗地下部对铬的吸收,钾浓度为1 600μmol.L^-1时,铬含量最小。随着钾浓度的提高,叶绿素含量、根系活力都增加,但丙二醛（MDA）含量变化没有呈现明显的规律。值得注意的是,当溶液中铬浓度在0-20μmol.L^-1之间时,地上部铬含量随着钾浓度的增大而逐渐减小,当铬浓度为40-100μmol.L^-1时,随着钾浓度的增大而呈增加趋势,说明高浓度铬处理时,钾可不同程度地促进铬由地下向地上部的转运。     

Effect of Ectomycorrhiza on Cu and Pb Accumulation in Leaves and Roots of Silver Birch (Betula pendula Roth.) Seedlings Grown in Metal-Contaminated Soil

A pot experiment was conducted to study the effects of high concentrations of available Cu and Pb in soil originated from the vicinity of a copper foundry in Poland (Cu, 2,585–3,725 mg kg^?1 d.wt.; Pb, 1,459–1,812 mg kg^?1 d.wt.) on the growth and chemical constituents of Betula pendula seedlings. Control plants grew in unpolluted forest soil. Dry matter accumulation in the plants during the growing season and root/leaf mineral content were determined. Colonization of birch roots by ectomycorrhizal (ECM) fungi also was evaluated, as was soil dehydrogenase activity for influence of the metals on soil microorganisms. The heavy metals negatively affected seedling growth, ECM colonization, and soil dehydrogenase activity. A reverse relationship was found between ECM abundance and heavy metal concentrations in birch leaves, indicating the potential of mycorrhizas to protect the aboveground part of young silver birch seedlings from elevated environmental levels of Cu and Pb.     

硫素营养胁迫对水稻根系和叶片超微结构的影响

通过水培试验,用电镜技术研究了不同浓度硫(S)索营养对水稻根系和叶片超微结构的影响.结果表明,受S素营养胁迫的水稻,其根系及叶片的超微结构均发生了显著的变化:低S胁迫会造成水稻叶片叶肉细胞内的叶绿体结构肿胀,基粒片层松驰、散乱,细胞器减少,线粒体结构被破坏,根系细胞内几乎没有内含物;S 浓度高则会使叶片叶绿体基粒片层致密、浓缩,无规则化,根系细胞发生质壁分离.这就从微观上进一步解释了水稻S索营养胁迫严重影响其生长发育的原因与机理,也为水稻S索营养的早期诊断提供了解剖学与形态学的依据.     

Kinetics of Zinc Uptake and Anatomy of Roots and Leaves of Coffee Trees as Affected by Zinc Nutrition

Abstract

The influence of silicon (Si) (2.5 mM), sodium chloride (NaCl) (100 mM), and Si (2.5 mM) + NaCl (97.5 mM) supply on chlorophyll content, chlorophyll fluorescence, the concentration of malondialdehyde (MDA), H₂O₂ level, and activities of superoxide dismutase (SOD; E.C.1.15.1.1.), ascorbate peroxidase (APx; E.C.1.11.1.11.), catalase (CAT; E.C.1.11.1.6.), guaiacol peroxidase (G-POD; E.C.1.11.1.7.) enzymes, and protein content were studied in tomato (Lycopersicon esculentum Mill c.v.) leaves over 10-day and 27-day periods. The results indicated that silicon partially offset the negative impacts of NaCl stress with increased the tolerance of tomato plants to NaCl salinity by raising SOD and CAT activities, chlorophyll content, and photochemical efficiency of PSII. Salt stress decreased SOD and CAT activities and soluble protein content in the leaves. However, addition of silicon to the nutrient solution enhanced SOD and CAT activities and protein content in tomato leaves under salt stress. In contrast, salt stress slightly promoted APx activity and considerably increased H₂O₂ level and MDA concentration and Si addition slightly decreased APx activity and significantly reduced H₂O₂ level and MDA concentration in the leaves of salt-treated plants. G-POD activity was slightly decreased by addition of salt and Si. Enhanced activities of SOD and CAT by Si addition may protect the plant tissues from oxidative damage induced by salt, thus mitigating salt toxicity and improving the growth of tomato plants. These results confirm that the scavenging system forms the primary defense line in protecting oxidative damage under stress in crop plants.     

Effect of Excess Cadmium and Zinc Ions on Roots and Shoots of Maize Seedlings

The effect of 8-day-old exposure maize seedlings with cadmium (Cd) or zinc (Zn), separately, are described with special attention being given to ultrastructural changes as well as changes of the growth. These elements, frequent pollutants found in the soil, were added as 1 mM solutions to nutrient solution used for roots and shoots of maize seedlings, investigated 8 days after germination. The symptoms of heavy metal toxicity were clear showing that Cd inhibits root growth more strongly than the shoots and more effectively than zinc ions. The results of scanning electron microscopy revealed changes in the leaf surface, particularly in the guard cells of the stomata. The ultrastructural analyses of the parenchyma mesophyll cells showed extensive chloroplast disorganization, mainly affecting the thylakoid membranes and grana.     

Distribution of Manganese(Ⅱ) Chemical Forms on Soybean Roots and Manganese(Ⅱ) Toxicity

Distribution of chemical forms of manganese(Ⅱ)(Mn(Ⅱ))on plant roots may affect Mn(Ⅱ)absorption by plants and toxicity of Mn(Ⅱ)to plants at its high level.The chemical forms of Mn(Ⅱ)on soybean roots were investigated to determine the main factors that affect their distribution and relationship with Mn(Ⅱ)plant toxicity.Fresh soybean roots were reacted with Mn(Ⅱ)in solutions,and Mn(Ⅱ)adsorbed on the roots was differentiated into exchangeable,complexed,and precipitated forms through sequential extraction with KNO_3,EDTA,and HCl.The exchangeable Mn(Ⅱ)content on the roots was the highest,followed by the complexed and precipitated Mn(Ⅱ)contents.Mn(Ⅱ)toxicity to the roots was greater at pH 5.5 than at pH 4.2 due to the larger amount of exchangeable Mn(Ⅱ)at higher pH.The cations Al~(3+),La~(3+),Ca~(2+),Mg~(2+),and NH_4~+competed with Mn(Ⅱ)for cation exchange sites on the root surfaces and thus reduced exchangeable Mn(Ⅱ)on the roots,in the order Al~(3+),La~(3+)Ca~(2+),Mg~(2+)NH_4~+.Al~(3+) and La~(3+) at 100μmol L~(-1) decreased exchangeable Mn(Ⅱ)by 80%and 79%,respectively,and Ca~(2+) and Mg2+at 1 mmol L~(-1) decreased exchangeable Mn(Ⅱ)by 51%and 73%,respectively.Organic anions oxalate,citrate,and malate reduced free Mn(Ⅱ)concentration in solution through formation of complexes with Mn(Ⅱ),efficiently decreasing exchangeable Mn(Ⅱ)on the roots;the decreases in exchangeable Mn(Ⅱ)on the roots were 30.9%,19.7%,and 10.9%,respectively,which was consistent with the complexing ability of these organic anions with Mn(Ⅱ).Thus,exchangeable Mn(Ⅱ)was the dominant form of Mn(Ⅱ)on the roots and responsible for Mn(Ⅱ)toxicity to plants.The coexisting cations and organic anions reduced the exchangeable Mn(Ⅱ)content,and thus they could alleviate Mn(Ⅱ)toxicity to plants on acid soils.     

水分状况及硼素营养对油菜苗期根系生长及硼营养效率的影响

采用温室盆栽试验 ,研究了不同土壤水分条件下施硼对油菜苗期根系生长、硼吸收、利用及其移动性的影响。结果表明 ,随土壤含水量、施硼量的下降 ,油菜根长、根体积、根系生长速率、根 /冠比减小 ,根系及地上部干物质积累降低 ,植株地上部硼浓度及含硼量下降。而硼利用效率、硼运移指数则随土壤含水量、施硼量的下降而升高。不同油菜品种的根系形态参数 (包括根长、根体积、根干重、根冠比及根系生长速率 )、硼利用效率及运移指数存在明显差异 ,即在相同条件下 ,V1根系较发达 ,硼利用效率、运移指数均高于V4 。研究认为 ,根系发达程度、硼利用效率及硼移动性大小是不同基因型油菜耐缺硼差异的重要因素。     

植被对降雨的再分配分析

 定量分析植被对降雨的再分配过程和植被影响雨滴溅蚀的方式,并比较了它们在被分配前后的击溅侵蚀能量。植被对降雨的再分配主要有3种形式:截流、透流和干流,其中,只有透流能溅蚀地面。再分配减少了溅蚀地面的雨量,但增加了雨滴直径。经过比较,结论如下:1)枯落物覆盖度与溅蚀能量呈线性负相关,枯落物覆盖度越大,溅蚀能量越小;2)在降雨量达到透流(经枝叶聚集部分)临界雨量以后,植被高度是所有植被特性中影响溅蚀能量贡献率最大的因子,植被越高,溅蚀能量越大;3)在降雨量达到透流(经枝叶聚集部分)临界雨量以后,雨滴终速度越大,植被所能减少的溅蚀能量越多。     

Relation between available boron and boron extracted from soils by hot water or phosphoric acid

Abstract

A measure of biologically available B (BAB) was obtained by assaying the amount of B removed from a small volume of soil by sunflowers grown until they displayed B deficiency symptoms. Four different mineral soils and one organic soil which had been treated in the field with variable lime and B applications 2 years prior to sampling were compared. The amount of B extracted with hot water from soils before cropping was well correlated with BAB. The B extracted by the more intensive hot water extraction methods was closely related to the absolute level of BAB. Digestion of soils with concentrated H₃PO₄ resulted in the dissolution of larger amounts of B than that extracted with hot water. The proportion of H₃PO₄ soluble B that was measured as BAB was quite variable. Thus H₃PO₄ was a less suitable extractant than hot water for assaying the amount of soil B available to plants during a short growing period. In no case was the difference between the B extracted from soils before and after cropping as large as the BAB values.     

High Sodium in Irrigation Water Caused B Toxicity at Low Soil Solution and Shoot B Concentration in Maize (Zea mays L.)

Sodium (Na) and calcium (Ca) in brackish water differentially affects boron (B) nutrition of plants grown on calcareous and salt-affected soils. A glasshouse experiment was conducted to evaluate the effect of brackish irrigation water with different sodium adsorption ratio (SAR_iw) [distilled-water control, 8, and 16 (mmol_c L^?1)^1/2] on B nutrition of maize. Plants were grown for 40 days with 5 levels of B (0, 1.29, 2.30, 3.22, and 4.46 mg kg^?1 soil). Boron application significantly improved plant growth at lower rates. High B rates and application of high SAR_iw decreased plant growth independently, and the reduction in growth was further aggravated due to combined effect of both B and high SAR_iw. Decreased growth was attributed mainly to increased shoot B and Na concentration, while decreased Ca concentration. These ionic changes also altered internal and external B requirements. Yield decrease was observed at lower B concentration in soil solution B and plants shoot grown with high SAR_iw than in plants grown with distilled water and low B application rates.     

不同水分条件下保水剂对黄瓜根系和叶片生理特征的影响

[目的]研究不同土壤干旱生境中保水剂对黄瓜根系和叶片生理特征的影响,探讨其生长效应与土壤水分的内在联系,为保水剂的合理施用和农田科学灌溉等提供一定的技术参考。[方法]利用盆栽模拟试验,通过定量灌水,系统研究在3种不同的土壤水分条件下,保水剂对黄瓜根际水分、根系形态特征、叶绿素荧光参数和叶片气孔性状等生理特性的影响。[结果](1)不同水分条件下,保水剂处理的黄瓜根系生长受到明显抑制。与对照相比,保水剂处理组在土壤含水量为田间持水量70%(FC₂)和55%(FC₃)时的总根长、平均根系直径、总根体积、根表面积和根干重均显著降低,分别降低了3.4%,24.2%,62.1%,41.0%和51.6%以上。(2)随着干旱胁迫的加剧,保水剂处理叶片的有效光合效率(F_v′/F_m′)和实际量子产量[Y(Ⅱ)]较对照出现先升后降的变化趋势,非光化学淬灭(NPQ)则呈相反的变化;尤其在FC₂和FC₃处理时,保水剂处理促使黄瓜叶片的光化学淬灭(q_P)较对照分...     

马尾松叶、根等浸提液对其种子发芽及苗木生长的影响

用马尾松成林的鲜叶、枯落叶、腐叶、活根、腐根及表土的水浸提液对其种子发芽及苗木生长的影响进行了试验。结果表明：上述６种侵提液处理与蒸馏水处理相比较，对马尾松种子的发芽、胚根生长和一年生苗木外生菌根的形成均有抑制作用；除鲜叶外，其他５种浸提液对马尾松一年生苗木高生长、主根长及鲜、干重有显著的抑制作用，而鲜时浸提液则有显著的促进作用，其抑制作用强弱的顺序是：土壤或腐叶＞腐根＞活根＞枯落叶＞鲜叶。这表明马尾松的叶、根组织及其残体含有对本种起抑制作用的物质存在，因而产生自毒作用。土壤是马尾松叶、根等器官在生长过程中分泌的及其残体在分解中产生的植物毒素的积聚场所，所以抑制作用最强。     

新式旱育秧苗叶片的解剖学观察

从显微水平和超微水平对杂交水稻汕优桂９９的新式旱育、传统旱育和半水育三种方式秧苗叶片的表皮、叶肉和叶脉进行观察，结果发现：表皮细胞外壁厚度、硅质乳突的数量、泡状细胞组相对大小、气孔器的密度；多环叶肉细胞数量；叶脉面积相对大小、叶脉上下方机械组织的细胞数等，均是新式旱育秧苗的叶片最大，传统旱育的次之，半水育的最小。观察结果从解剖学方面说明了新式旱育秧苗素质好的原因所在     

水稻核糖核酸酶T2蛋白质在叶片生长和盐胁迫过程中的表达研究

核糖核酸酶(Ribonucleases,RNase,RNS) T2普遍存在于各种生物中,其保守性提示了功能的重要性.在水稻基因组中有8个RNase T2成员,本试验采用基于抗体的蛋白质组学策略,用免疫印迹(Western Blotting,WB)技术检测了它们在叶片生长及盐胁迫条件下的表达,发现OsRNS1-OsRNS7蛋白质在叶片中有表达,其中OsRNS4主要在苗期表达,提示其在苗期发挥作用,其它蛋白质主要在成株期表达,但没有检测到OsRNS8的表达;水稻OsRNS4在盐胁迫条件下表达上调,提示其可能在盐胁迫应答过程中发挥作用,其它RNase T2蛋白质的表达大多随盐胁迫时间的延长而下降.将RNase T2蛋白质的表达与转录信号进行比较,发现二者在部分基因中有一定的相关性.本试验获得的数据为揭示水稻RNase T2基因的功能提供了线索.     

干旱胁迫下2种香蕉幼苗叶片和根的主要渗透调节物质的变化

本文研究了不同干旱胁迫下抗旱性不同的帝王蕉和粉蕉幼苗叶片和根系的可溶性蛋白质和可溶性糖主要渗透调节物质的含量变化。结果表明：2种香蕉幼苗叶片可溶性蛋白质和可溶性糖含量随着干旱胁迫程度的增加而显著增多;根系可溶性蛋白质和可溶性糖含量并未持续上升,而是重度胁迫低于中度胁迫,但仍高于对照和轻度胁迫。干旱胁迫后,除帝王蕉根系可溶性糖含量外,帝王蕉根系可溶性蛋白质、粉蕉根系可溶性蛋白质和可溶性糖含量在3个胁迫程度下增加幅度均大于叶片增加幅度,且粉蕉较帝王蕉更能适应干旱胁迫环境。本文将为香蕉抗旱品种选育和栽培提供一定的理论依据和实践意义。     

油菜细胞质雄性不育系根和叶mtDNA的提取

本研究以甘蓝型油菜(Brassica,napus)细胞质雄性不育系PolA及其保持系PolB、陕2A及其保持系陕2B 幼苗为材料,分别提取其根和叶线粒体DNA(mtDNA),并对所提取的油菜mtDNA进行检测.结果表明,在同等条件下幼根所提取的mtDNA平均含量为3250 ng/g FW,约为幼叶所提取mtDNA含量的6.5倍,而且所提取的mtDNA纯度较高;琼脂糖凝胶电泳检测结果也显示,油菜幼根所提mtDNA较幼叶所提mtDNA有更为清晰的条带.另外,油菜线粒体基因的PCR扩增结果显示,油菜幼根所提mtDNA扩增条带的重复性和稳定性也优于幼叶所提mtDNA.因此,用油菜幼根提取mtDNA是一条较好的途径.     

低钾胁迫对烟草幼苗叶中基因表达的影响

为探索在低钾胁迫下烟草幼苗基因表达谱的变化,对烟草幼苗进行了0、6、12、24 h低钾胁迫,并利用基因芯片技术分析了烟草幼苗基因表达谱的变化。结果表明,与对照相比,处理组基因表达量变化在2倍以上的差异表达基因共有3 790个。这些差异表达基因所行使的功能多达18种,包括抗氧化活性、催化活性、酶调活性,并参与应激反应、发育过程以及代谢过程等。在差异表达基因中,涉及到响应非生物刺激相关差异表达基因有417个(281个上调、136个下调)、光合作用基因有21个(10个上调、11个下调)、光合色素合成相关基因9个(6个上调、3个下调)以及植物激素代谢相关基因6个(5个上调、1个下调)。研究结果可为烟草钾营养的分子机制研究提供借鉴。