Differences in Root and Shoot Response to Limited N-supply in Oat and Spring Barley

Oat and spring barley cultivars, varying in origin and date of release, were examined in soil boxes with sloped glass-face. Considerable genotypic differences were found in shoot and root response to high and low nitrogen supply. Oat cultivars, representing a wider germplasm collection, exhibited a stronger and partially different shoot and root response to applied N-levels than barley cultivars. Cultivar-fertilization interaction effects were significant for seminal and adventitious root variation. Genotypic specificity (plasticity) in root response, as revealed in some oat and barley cultivars with a deeper penetration and more vigorous root growth under the low N-supply, was recognized to be a valuable adaptive characteristic for breeding plants on light-textured soils.     

玉米/蚕豆、小麦/蚕豆和大麦/蚕豆间作体系地上部、 地下部生物量及作物含氮量分析

【研究目的】该盆栽试验研究了在不同分隔方式下三种禾本科作物与蚕豆间作对间作作物地上部、地下部生物量及吸氮量的影响。【方法】首先采用三种分隔方式（塑料膜分隔,尼龙网分隔和无分隔）建立了同一作物组合条件下种间根系相互作用的不同强度;其次选用竞争能力不同的三种禾本科作物（大麦、小麦和玉米）与蚕豆间作,建立了禾本科和豆科作物的竞争强度不同的作物组合。【结果】首先,与三种禾本科作物间作,以及同一间作体系不同分隔方式,对蚕豆地上部、地下部生物量的影响不大;仅与小麦间作蚕豆地上部生物量无分隔显著高于尼绒网分隔。其次,禾本科作物地上部生物量,玉米和大麦显著高于小麦,分别高出15.3%和16.5%;三种禾本科作物地下部生物量,玉米显著高于大麦,高出30.5%,大麦显著高于小麦,高出50.8%;同一间作体系不同分隔方式,对玉米、小麦和大麦地上部和地下部生物量影响显著。再次,大麦全氮含量显著高于玉米和小麦,分别高出16.5%和19.7%,与三种禾本科作物对土壤氮素的竞争能力相一致,大麦大于小麦和玉米;同玉米间作蚕豆全氮含量显著高于同小麦和大麦间作蚕豆,分别高出11.2%和5.6%。最后,玉米,同小麦和大麦间作蚕豆无分隔处理全氮含量显著高于塑料膜分隔,表现出间作优势。【结论】蚕豆的生长受间作禾本科作物的影响不显著;然而大麦/蚕豆间作体系利用氮素最充分;间作玉米在氮素营养上显著受益于同蚕豆的间作;并且在三种间作体系里,根系完全相互作用时有利于作物氮素的累积。     

不同植物生长物质对水培黄瓜幼苗生长和根系发育的影响

考察了生长素类、赤霉素类、DA-6、复硝酚钠、海藻肥、细胞分裂素、脱落酸、水杨酸钠、多效唑、木醋液等16种生长物质对水培黄瓜幼苗生长和根系发育的影响。结果表明DA-6、赤霉素GA（4+7）对幼苗生长和根系发育有明显促进作用。作用浓度下的海藻肥在处理初期可促进新叶和侧根发生,而对主根伸长有明显抑制。萘乙酸钠、水杨酸钠、脱落酸等对水培幼苗生长表现出强烈的抑制和毒性。研究结果可为在田间应用上述植物生长物质提供借鉴。     

盐份对大麦幼苗形态建成的影响

盐浓度对作物生长的影响一直是研究的热点。为探讨盐胁迫对大麦幼苗形态建成的影响,以4个耐盐性不同的大麦品种为材料,研究了不同时期、不同盐浓度(NaCl)对大麦幼苗根数、根长、芽长及鲜重的影响。研究结果表明:(1)大麦普遍具有较强的耐盐能力,但不同品种的耐盐能力存在显著差异。就大多数大麦品种而言,0.3%以下盐水发芽对幼苗主要器官的生长影响不大,能较好地完成幼苗形态建成,0.5%以上盐水对幼苗主要器官的生长发育产生的影响较大。(2)除不同盐份对发芽10d幼苗芽长的影响不显著外,盐份对发芽5d和10d大麦幼苗主要性状产生了显著的影响,但随着发芽时间的延长,盐浓度对幼苗主要性状的影响程度均有所下降。     

Effect of Concentration of Seed Hardening Chemicals on Physiological Characters of Pearl Millet (Pennisetum typhoides Stapf and Hubb)

A laboratory study was taken up in the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore in the year 1986 to fix optimum concentration and to evaluate the efficiency of CCC (2-chloroethyl trimethyl ammonium chloride), succinic acid and sodium chloride as seed hardening chemicals for pearl millet. The study revealed that CCC 100 ppm, succinic acid 0.15 per cent and sodium chloride 1 per cent concentrations were better in improving the germination per cent, root : shoot ratio and vigour index of pearl millet.     

膜下滴灌高产棉花根、冠生物量累积特性研究

在新疆膜下滴灌大田条件下,选用新陆早43号和新陆早45号2个棉花品种,测定不同产量水平棉田棉株根系生物量及其空间分布、地上部生物量、根冠比等,分析滴灌棉花产量形成过程中根、冠生物量的累积特征。结果表明:与一般产量棉田及中低产棉田相比,高产棉田在整个生育期根系生物量较高、中下层根系分布比例较大,棉株总生物量、地上部生物量、棉铃生物量均较高,根冠比较低;产量构成因子表现为总铃数较多、铃重较高。高产棉花由于其生物量快速累积起始时间较早、累积速率快,进而棉株根系生物量、总生物量累积多。因此,根据参试棉花品种的生育特点,在适期早播促生育进程提前、前期营养器官稳健生长的前提下,采取水肥后移或适当推迟停水时间,可适度增加棉花中下层根系分布,降低根冠比,提高光合产物向棉铃的分配比例,增加铃重,进一步提高棉花产量。     

Genotypic differences in Zn efficiency of Medicago species

Nineteen annual Medicago genotypes from eight species were grown in Mt. Compass sand at three levels of soil Zn application (0, 0.1 and 0.9 mg Zn kg^-1) to achieve Zn status from deficiency to adequacy. Genotypes differed in growth response: under Zn deficiency, those classified as Zn-efficient had less reduction in shoot growth, a higher root mass, greater concentration of Zn in the shoot and total Zn content per plant, and a stable shoot/root ratio compared with Zn-inefficient genotypes. While seed Zn content did not influence the Zn-efficiency ranking, it did affect yield, and so it plays an important role in yield response and Zn accumulation as Zn supply decreases. This revised version was published online in July 2006 with corrections to the Cover Date.     

酚酸类物质对野燕麦萌发及幼苗生长的影响

摘要：本试验采用不同浓度的两种酚酸类物质及其两者的混合物对野燕麦种子及幼苗进行处理,研究其对野燕麦发芽率、幼苗形态指标及其某些生理指标的影响。结果表明：酚酸类物质及其混合物可以显著延缓野燕麦种子发芽所需要的时间,降低最终的萌发率,对野燕麦幼苗的生理指标及干物质积累有一定的抑制作用,根系活力与叶绿素含量也有不同程度的下降,同时使幼苗体内丙二醛的含量显著增加。     

Development of a Model of Lodging for Barley

Lodging in barley (Hordeum vulgare L.) can result either from buckling of any part of the stem (stem lodging) or failure of the root–soil anchorage system (root lodging). A framework for calculating the risk of stem lodging is developed which takes account of the shoot's height, ear area, natural frequency, weight, the flexural rigidity of the stem and changes in stem strength along its length. The model predicted that stem lodging in barley cultivars would occur half way up the stem, and stem lodging in wheat would occur close to the soil surface. These predictions are consistent with general observations of stem lodging in barley and wheat. The higher position of stem lodging in barley, compared with wheat, was caused by the greater flexibility of the barley stems and a more rapid reduction in stem strength up the stem. A sensitivity analysis showed that the stem diameter of the middle internodes had the greatest effect on the risk of stem lodging. Changes to ear area, drag coefficient, crop height, shoot natural frequency and the strength of the stem wall had a moderate influence. Measurements of anchorage strength in barley and wheat plants indicated that the mechanism of anchorage failure was the same for both species and that a model of root lodging developed for wheat could be successfully adapted for barley.     

Influence of a Triazole Plant Growth Regulator on Root and Shoot Development and Nitrogen Utilisation of Oilseed Rape (Brassica napus L.)

A factorial experiment with 3 nitrogen (N) levels and 4 application rates of the triazole type plant growth regulator (PGR), BAS 111 W = l-phenoxy-3-(1H-1,2,4-triazol-1-yl)-4-hydroxy-5,5-dimethylhexane, was conducted in hydroponics to study the influence on N uptake and morphological changes of oilseed rape. The following results were obtained:
–Increased N level of the nutrient solution increased plant height and root and shoot weight. Enhanced N uptake caused a higher N concentration of root and shoot.
–Increasing PGR application rates reduced plant height and shoot biomass production; this reaction was stronger at higher doses of N.
–Root weight, root length, root diameter and root surface area were increased by N application. None of these parameters was significantly altered by the PGR. This resulted in increased root-shoot-ratios at higher PGR rates.
–As a consequence of reduced shoot production PGR application resulted in increased concentrations of N. The root reacted similarly but to a lesser degree.     

丁香酸、对羟基苯甲酸处理对野燕麦萌发及幼苗生长的影响

采用不同浓度的两种酚酸类物质及其混合物对野燕麦种子及幼苗进行处理,测定其对野燕麦种子的萌发率、幼苗的营养生长及某些生理指标的影响。试验结果表明：酚酸类物质及其混合物能显著延缓野燕麦种子的萌发时间,降低最终的发芽率,对野燕麦幼苗的根长和苗长及干物质的积累也有一定的抑制作用。同时发现这两种酚酸类物质及其混合物能降低野燕麦幼苗的根系活力,加速丙二醛在幼苗体内的积累,而且随着浓度的增加对根系活力的抑制作用越来越大,幼苗体内的丙二醛的积累量也越来越大。     

类大麦茶风味蒲公英饮料的研究与开发

以蒲公英根为原料,研究开发一款新型的类大麦茶风味蒲公英保健饮料。采用单因素试验确定蒲公英原汁的制备工艺,以白砂糖、柠檬酸、稳定剂等为添加剂进行调配,通过正交试验优化法确定最佳饮料配方;测定蒲公英原汁中的功能成分多糖的含量,并对饮料的品质指标进行评价。结果表明,采用粉碎程度为最粗粉的蒲公英根原料,按料液比1∶30,煎煮1.5h制得蒲公英原汁,此时多糖含量和类大麦茶风味最佳,多糖含量为8.5 mg/100 m L;正交试验优化最佳饮料配方原汁添加量40%,白砂糖添加量8%,柠檬酸添加量0.1%,稳定剂添加量0.1%加水混合,成品汤色棕橙、通透明亮、清香甘甜,富有类大麦茶风味,各项质量指标符合国家标准。     

不同施肥水平对三色堇根冠比和壮苗指数的影响

采用随机完全区组设计,对不同施肥条件下三色堇有机基质穴盘苗的根冠比和壮苗指数进行了较系统的研究。施用氮肥后,与对照相比,三色堇穴盘苗根冠比和壮苗指数显著变小。4 g/L和8 g/L的氮肥施用量对三色堇穴盘苗根冠比的影响没有显著的差异。4 g/L和8 g/L的氮肥施用量对地下部都产生了胁迫作用,两水平施肥量对根系的抑制程度大致相等。磷钾肥对三色堇幼苗根冠比的影响没有规律性且不显著,但磷钾肥使三色堇穴盘苗的壮苗指数有一定程度的降低。与对照相比,微肥施用后各苗龄在施肥后显著增加了三色堇穴盘苗的根冠比值,但对三色堇穴盘苗的壮苗指数却无明显影响。     

Effects of Irrigation at Different Growth Stages on Vegetative Growth of Mung Bean, Vigna Radiata (L.) Wilczek, in Dry and Intermediate Zones of Sri Lanka

Mung bean crops in the subhumid zones of Sri Lanka experience significant drought periods. The objective of this study was to quantify the growth response of mung bean to irrigation at different phenological stages and thereby determine the optimum irrigation regime to maximize growth. Four field experiments were conducted at two sites in 1995 and 1996. The crop duration of mung bean was divided into three stages: vegetative (from germination to appearance of first flower), flowering (from appearance of first flower to 75 % pod initiation) and pod-filling (from 75 % pod initiation to maturity). Eight treatments were devised to represent all possible combinations of irrigation at the three stages. Maximum leaf area index (ranging from 0.6 to 2.6 across treatments) and total leaf area duration were increased significantly by irrigation during the vegetative stage. Specific leaf weight decreased and maximum total crop biomass (150–400 g m⁻²) increased with the number of stages irrigated. Irrigation decreased the absolute root biomass and increased the shoot:root ratio. It is concluded that, in this agroclimatic zone of Sri Lanka, irrigation of mung bean during the vegetative stage is critical for maximizing leaf area. However, biomass production can be maximized by increasing the number of stages irrigated irrespective of irrigation at any specific stage.     

化感物质对玉米种子及苗期生长特性的影响

为研究秸秆中化感物质对玉米种子萌芽和苗期生长特性的影响,设置不同浓度对羟基苯甲酸、邻苯二甲酸、苯甲酸、丁香酸和香草酸混酸液为处理,以蒸馏水为对照(CK),培养玉米种子及幼苗并测定其生理指标。结果表明：混酸液处理显著降低玉米种子发芽率和胚根长;100 mg/L、200 mg/L和500 mg/L混酸液处理极显著降低胚轴长和玉米苗期根系活力。混酸处理过氧化氢酶活性均高于CK,无显著差异。随混酸液浓度升高,玉米叶片丙二醛含量逐渐增加。50 mg/L以上浓度混酸液对玉米种子及苗期生长均有抑制作用。     

Recovery Strategy Following the Imposition of Episodic Soil Moisture Deficit in Stands of Peanut (Arachis hypogaea L.)

Peanut stands often face water deficits in the tropics and subtropics, especially in drought-prone areas of India. The effect of drought on peanut production has previously been studied. However, there is a lack of information on the post-stress recovery mechanism. The objective of this study was to investigate the recovery mechanism after relief of water stress. The effect of short-term drought applied (for 12 days) at the pre-flowering, peak flowering and pod-filling stages on chlorophyll (Chl) pigments, water use efficiency (W_ue), quantum yield (Q_y), root/shoot ratio (R:S), relative growth rate (RGR), net assimilation rate (NAR) and flower production during stress and subsequent post-stress recovery was examined. The leaf water potential (ψ_leaf) and leaf relative water content (RWC) in plants subjected to water deficit were reduced to 1/10 and 2/3, respectively, of the corresponding control values. Moisture deficit significantly reduced Chl a and b concentrations, the Chl a/b ratio, stomatal conductance, photosynthesis, W_ue and Q_y. However, a strong recovery of these traits was noted after rewatering, which led to onset of fresh growth on post-stress, with a marked increase in RGR and NAR and a flush of flowering. Drought significantly enhanced R:S, which accelerated post-stress recovery. Peanut stands exhibited excellent ecophysiological recovery with the post-stress onset of fresh growth. This strong recovery mechanism found in peanut stands suggests that peanut has high environmental plasticity.     

二倍体野燕麦染色体的C-带分析

采用C-带技术对二倍体野燕麦根尖细胞染色体进行了带型分析,以研究该野燕麦染色体的C-带特点.结果表明:二倍体野燕麦具有7对染色体,其上共有35条带,其中长臂具有带纹19条,包括13条中间带(I),6条末端带(T);短臂具有8条带纹,包括2条中间带(I),6条末端带(T),另外还有l条随体带(S)以及7条着丝点带(C),其带型公式为2 n=14=2CIT+ +2 CIT+8 CI+ T+2 CI+ T+S.二倍体野燕麦染色体组成为CC,核型为2A,属于较对称核型,进化指数为7.     

植物激素ABA调控侧根生长发育的研究进展

侧根构型直接影响植物根系形态建成,是植物整个根系的重要组成部分,在植物抗逆反应中起着重要作用。为了研究植物激素脱落酸(ABA)调控侧根生长发育的分子机制,本研究归纳了ABA在侧根发育中的信号传递,揭示了ABA在侧根起始中的双重作用和ABA对侧根分生组织活性的抑制作用。并分析了在侧根发育过程中ABA与其他调控因素包括活性氧(ROS)、生长素、细胞分裂素、碳和氮信号,以及盐胁迫间的交叉对话机制,指出ABA通过诱导根中ROS的产生,拮抗生长素和协同细胞分裂素的作用从而达到抑制侧根生长发育;ABA还参与了复杂的碳和氮信号调控的侧根发育过程;此外,ABA信号介导了盐胁迫对侧根发育起始的抑制。ABA调控侧根生长发育的分子机制的揭示可以为改善植物根系性状,提高作物抗逆性提供指导作用,然而,ABA对根生长调控的分子机制还不是很清楚,根系形成也十分复杂,因此需要更多的努力。     

Influence of Seed-Bed Preparation and Straw Utilization on Root Growth of Barley in Monoculture

Root system size of spring barley as measured by means of its electrical capacity was evaluated in the 12th till 14th year of monoculture. It was significantly greater in variants with burnt straw in situ or with turned under straw than in variant with straw cleared away. The kind of seed-bed preparation did not influenced root system size significantly, but its interaction with straw utilization and with term of measurement was significant. The larges root sytem was found in combination with minimal seed-bed preparation and burnt straw (relatively 100) and the smallest in combination with minimal seed-bed preparation and straw cleared away (relatively 62).     

Influence of Root-Applied Epibrassinolide and Carbenoxolone on the Nodulation and Growth of Soybean (Glycine max L.) Seedlings

24-Epibrassinolide belongs to the brassinosteroid family of plant hormones, and carbenoxolone is a synthetic analogue of glycyrrhizic acid that inhibits enzymes important in steroid and prostaglandin action in animals. The effect of these compounds on root nodulation, root growth and shoot growth of Glycine max (L.) Merr. cv. Tracy M was examined. Epibrassinolide reduced total nodulation, plant wet weight, root length, shoot length, first internode length and number of lateral roots. Effects were observed at concentrations as low as 0.1 μ M . Carbenoxolone reduced lateral root formation, but did not reduce nodule numbers, root length or weight, nor stem length or weight.