航天诱导的凤仙花突变株性状及减数分裂过程的研究

本文报道了种子经神舟 4号飞船搭载的凤仙花突变植株的性状及减数分裂过程的变化。该突变株在花色及花型等宏观性状上有很大变异。观察减数分裂过程 ,发现其小孢子母细胞减数第 1次分裂前期基本正常 ,但到后期Ⅰ出现染色体分配的严重不均 ,并出现落后染色体、分散染色体等。减数第 2次分裂完成时 ,多数形成 4分孢子 ,但同时也出现各种形式的多分孢子。小孢子中染色体数目从 1～ 2 1条不等 ,甚至多达 30多条。小孢子的形状和大小变异明显 ,且小孢子的大小与所含染色体的数目呈正相关。碘液染色检查发现绝大多数花粉不育 ,并与该突变株的低结实率一致。分析认为花粉的大小差异和花粉的育性与减数分裂异常有关 ,而这些现象都是航天诱变造成的     

铝诱导蚕豆气孔保卫细胞凋亡研究

植物叶表面的气孔保卫细胞是研究信号转导的模式实验系统,对环境变化反应灵敏而准确,采用蚕豆叶面气孔保卫细胞,研究了铝（AlCl3）对细胞的毒性效应。结果表明,在1～10 mmol.L^-1范围内,AlCl3可使气孔保卫细胞活性降低,部分细胞死亡,且随着浓度的增高细胞死亡率增高;死细胞呈现核固缩、核降解、凋亡小体等典型凋亡特征。凋亡抑制剂Z-Asp-CH2-DCB或TLCK与AlCl3共同作用时,保卫细胞死亡率显著降低;一定浓度的抗坏血酸（AsA）或过氧化氢酶（CAT）以及Ca2＋螯合剂乙二醇四乙酸酯（EGTA）或Ca2＋通道抑制剂LaCl3与AlCl3共同作用时,细胞死亡率降低。研究结果表明,铝诱导的蚕豆保卫细胞死亡可能是一种细胞凋亡过程,由胁迫诱发的活性氧介导,通过激活质膜钙通道,引起胞内Ca2＋水平改变,进而介导细胞凋亡。     

镉诱导的茶苗茎尖核酸代谢与细胞超微结构变化研究

试验研究茶苗经不同浓度Cd2 培养液培养12d结果表明,0 .0 5mmol/ L浓度Cd2 对茶苗相对生长量无明显影响,Cd2 浓度≥0 10mmol/ L时随处理浓度增加和时间延长,茶苗生长受抑程度逐渐加大。培养12d时0 0 5mmol/ L浓度Cd2 处理茶苗细胞内核糖体数量和核酸含量均高于对照,超过此浓度的处理其核糖体大量消亡,核酸含量显著降低,其中DNA含量变幅小于RNA。0 0 0～0 10mmol/ L浓度Cd2 处理RNase活性随浓度增加而升高,>0 2 5mmol/ L浓度Cd2 处理RNase活性则随浓度增加而降低。电镜观察结果表明轻度Cd2 毒害表现为核仁解体,染色质凝聚,核膜间隙扩大,核染色质进入核膜间隙,严重者出现核变形收缩,核膜破裂,核染色质扩散降解最终核解体     

阿魏酸诱导蚕豆枯萎病发生及根系组织结构损伤的化感效应

  【目的】  酚酸类化合物是多种农作物根际土壤中常见的自毒物质，化感自毒物质与土传病害发生密切相关。研究阿魏酸对枯萎病发生的促进效应及机理，为阐明连作自毒物质–病原菌–寄主抗病性互作效应提供参考。  【方法】  采用水培试验研究阿魏酸对蚕豆幼苗生长和枯萎病发生的影响。在蚕豆幼苗长至4～6片真叶时，将其移入2 L Hoagland 营养液中进行培养，其中阿魏酸浓度分别为0、50、100、200 mg/L。待阿魏酸处理2 天后，加入25 mL 1 × 106 cfu/mL的尖孢镰刀菌孢子悬浮液。继续培养40天后，取样调查植株生长状况和枯萎病发病率。利用显微镜观察蚕豆根系细胞组织结构的变化，通过室内培养试验研究尖孢镰刀菌菌丝生长和致病力对阿魏酸胁迫的响应。  【结果】  与无添加阿魏酸 (0 mg/L) 处理相比，添加阿魏酸处理显著抑制蚕豆幼苗的生长，且阿魏酸浓度越高抑制作用越强。本试验条件下，阿魏酸处理显著提高蚕豆枯萎病发病率300.0%～500.0%，显著增加病情指数113.3%～1666.7%，发病率和病情指数均在阿魏酸处理浓度200 mg/L下达到最大值。阿魏酸处理抑制尖孢镰刀菌的菌丝生长，显著提高尖孢镰刀菌产生的果胶酶、纤维素酶、淀粉酶和蛋白酶活性44.8%～59.0%、78.2%～145.6%、975.6%～2435.4%和165.1%～622.9%；显著提高枯萎酸含量107.6%～236.2%。阿魏酸胁迫下，蚕豆根系表皮细胞扭曲变形，木质部导管变细，导管壁增厚，胶状物和内含物充满整个细胞，阻碍营养物质和水分的正常运输，进而加速蚕豆枯萎死亡。  【结论】  阿魏酸胁迫虽然抑制尖孢镰刀菌的菌丝生长，但显著提高蚕豆根系细胞壁降解酶活性和枯萎酸含量，进而增加尖孢镰刀菌致病力，加速根系细胞组织结构损伤，促进尖孢镰刀菌侵入蚕豆根系，加剧枯萎病发生和危害。阿魏酸在蚕豆连作障碍中扮演着初始诱因的角色。     

2,4—D处理小麦叶面诱导类根瘤的观察

通过以２００ｍｇ／ｋｇ的２，４－Ｄ处理适龄的小麦叶面，并同时接种固氮菌液，诱导出小麦类根瘤，经过ＩＮＴ试剂检验和电镜切片观察，明确了小麦诱发根瘤内确有菌休存在，２，４－Ｄ叶面处理可以起到根部处理诱发含菌类根瘤的同样效果。     

Autofertility in a pure line faba bean (Vicia faba L.) germplasm collection

Summary A pure line faba bean germplasm collection (BPL) was derived by a process of cyclic single plant progenies starting in 1979 through 1985. In 1985/86, 840 of these pure line accessions from 677 original populations from 41 countries were evaluated for autofertility by comparing the mean of five plants where all flowers were tripped vs. five plants with no tripped flowers for number of seeds produced (seed index). In a replicated trial grown at the same time, seed yield, 100 seed weight, number of pods per plant, seeds per pod, and number of flowers per inflorescence were also evaluated. A high number of BPL accessions failed to set seeds in the screen houses without tripping, the mean seed index measure of autofertility was 0.51 with a C.V. of 74.2%. There were marked differences among countries of origin for autofertility, with Egypt having the highest (SI = 0.94) and the USSR the lowest (SI = 0.26) autofertility, however, most countries expressed a large range, suggesting that breeders should first look in their own material for this trait rather than searching in exotic germplasm. In general, there was a higher level of autofertility in Middle Eastern countries that may be due to natural selection for non-dependency on pollinators for high yield. Contrary to the findings of others, large seeded accessions had a high autofertility (SI = 0.704) compared to small seeded accessions (SI = 0.384), however, both had similar ranges. In general, there was no significant correlations among autofertility and yield and its components. The variability found in this large pure line collection for autofertility is of potential use for developing cultivars not dependent on insect populations for high yield and for developing self-pollinated faba bean.     

Genetic diversity in spring faba bean (Vicia faba L.) genotypes as revealed by high-throughput KASP SNP markers

Genetic Resources and Crop Evolution - Faba bean is one of the oldest legume crop grown around the world for its cheap source of protein and for being used in crop rotation with cereals to improve...     

Geographic dispersion and varietal diversity in Vicia faba L.

Summary Twenty-six faba bean (Vicia faba L.) populations, from five geographic areas and five varietal types have been assayed electrophoretically for variation in seven isozyme systems. Isozyme frequencies in populations, botanical varieties and geographical areas were submitted to the principal component analysis (PCA). Varieties grouped together showed no differences among them except for isolated populations. Populations from Ethiopia and China lay far apart in PCA from those of other origins. It seems that no genetic divergence at the isozyme level took place during the varietal formation and dispersion process, except when geographical isolation of the population occurred. The results support the hypothesis of an isolation of the crop in Ethiopia and in China.     

Jasmonic acid alleviates negative impacts of cadmium stress by modifying osmolytes and antioxidants in faba bean (Vicia faba L.)

We examined the role of jasmonic acid (JA) in faba bean under cadmium (Cd) stress, which reduces the growth, biomass yield, leaf relative water content (LRWC) and pigment systems. Hydrogen peroxide (H₂O₂) and lipid peroxidation (malondialdehyde [MDA]) levels increased by 2.78 and 2.24-fold, respectively, in plants under Cd stress, resulting in enhanced electrolyte leakage. Following foliar application to Cd-treated plants, JA restored growth, biomass yield, LRWC and pigment systems to appreciable levels and reduced levels of H₂O₂, MDA and electrolyte leakage. Proline and glycine betaine concentrations increased by 5.73 and 2.61-fold, respectively, in faba bean under Cd stress, with even higher concentrations observed following JA application to Cd-stressed plants. Superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase levels rose by 87.47%, 130.54%, 132.55% and 37.79%, respectively, with Cd toxicity, with further enhancement of antioxidant activities observed following foliar application of JA. Accumulation of Cd in roots, shoots and leaves was also minimized by external supplementation of JA. In conclusion, JA mitigates the negative impacts of Cd stress in faba bean plants by inhibiting the accumulation of Cd, H₂O₂ and MDA, and by enhancing osmolyte and antioxidant activities that reduce oxidative stress.     

Biological nitrogen fixation in faba bean (Vicia faba L.) in the Ethiopian highlands as affected by P fertilization and inoculation

 N₂ fixation by leguminous crops is a relatively low-cost alternative to N fertilizer for small-holder farmers in developing countries. N₂ fixation in faba bean (Vicia faba L.) as affected by P fertilization (0 and 20 kg P ha^–1) and inoculation (uninoculated and inoculated) with Rhizobium leguminosarium biovar viciae (strain S-18) was studied using the ¹⁵N isotope dilution method in the southeastern Ethiopian highlands at three sites differing in soil conditions and length of growing period. Nodulation at the late flowering stage was significantly influenced by P and inoculation only at the location exhibiting the lowest soil P and pH levels. The percentage of N derived from the atmosphere ranged from 66 to 74%, 58 to 74% and 62 to 73% with a corresponding total amount of N₂ fixed ranging from 169 to 210 kg N ha^–1, 139 to 184 kg N ha^–1 and 147 to 174 kg N ha^–1 at Bekoji, Kulumsa and Asasa, respectively. The total N₂ fixed was not significantly affected by P fertilizer or inoculation across all locations, and there was no interaction between the factors. However, at all three locations, N₂ fixation was highly positively correlated with the dry matter production and total N yield of faba bean. Soil N balances after faba bean were positive (12–58 kg N ha^–1) relative to the highly negative N balances (–9–44 kg N ha^–1) following wheat (Triticum aestivum L.), highlighting the importance of rotation with faba bean in the cereal-based cropping systems of Ethiopia. Received: 13 January 2000     

Nitrate uptake by Vicia faba L. Plants: A physiological approach 1

This study was conducted to obtain information on the properties of the nitrate (NO₃ ^‐) uptake system in Vicia faba. The results showed that in plants grown in the absence of NO₃ ^‐, they cannot absorb it upon initial exposure to this anion. When this plant makes contact with environmental NO₃ ^‐, NO₃ ^‐uptake by the roots is progressively induced. However, in NO₃ ^‐‐grown plants, the uptake system is yet induced so they had the ability to take up NO₃ ^‐ at high rates from the beginning. The Michaelis’ constant (K,_M) and maximum uptake rate (V_max) were estimated from measurements of NO₃ ^‐ depletion in the uptake medium. The apparent K_M value for net NO₃ ^‐ uptake in induced V. faba plants was 60 μM and the corresponding V_max 0.44 umol NO₃ ^‐ (g FW)^‐1 h^‐1. This last value was low compared with that of other species, while K_M is in the range for other higher plants. From the results of our experiments at low and high NO₃ ^‐ concentrations, we discuss the possibility of the existence of two NO₃ ^‐ uptake systems, one of a high affinity (functioning at low NO₃ ^‐concentrations) and another of low affinity (operative at high NO₃ ^‐ level in the medium).     

Transport of phosphorus in leaf veins of Vicia faba L.

The plant nutrient phosphorus (P) is spread throughout the plant within the transpiration stream after uptake in the form of phosphate via the roots. Short‐term distribution is therefore strongly dependent on transpiration rather than on sinks, so that P mainly enters adult leaves. The objective of this work was to investigate the transport of phosphate in leaf veins and its distribution within the leaf. Experiments were performed with broad bean (Vicia faba L. var. Scirocco) using radioactively labeled phosphate. In a relatively new approach, the tracer was monitored by a sensitive imaging plate using Fujifilm's Bioimaging Analyzer System. Radioactive label could be monitored in fresh leaves (without fixing) using exposure times of only 5–20 min. For this reason, the method offered the possibility to obtain several subsequent autoradiographic images of the same sample after different feeding times. Phosphate tracer quickly reached small veins, which were then more intensely labeled than the tissue between them. Within the first 15 min, intercostal fields were only slightly stained. After application of phosphate tracer onto the leaf blade, export from the leaf was pronounced and started within 30 min. Phosphorus is effectively redistributed from adult leaves to sinks such as the terminal bud or growing root tips. Using the imaging method, an impression of the high velocity and effectiveness of this process was obtained. The results furthermore imply that leaf veins may be one of the most important locations where exchange between xylem and phloem transport takes place, although exchange between xylem and phloem was also observed in the shoot axis and in the petioles.     

Phenolics, phytic acid, and phytase in Canadian-grown low-tannin faba bean (Vicia faba L.) genotypes

Thirteen low-tannin faba bean genotypes grown at two locations in north central Alberta in 2009 were evaluated to investigate the variation in seed characteristics, phenolic and phytate contents, and phytase and antioxidant activities and to elucidate the relationship of these components as a breeding strategy. Seed characteristics including color were predominantly genotype dependent. The faba bean genotypes with total phenolic content ranging from 5.5 to 41.8 mg of catechin equiv/g of sample was linearly related to tannin content and the best predictor of antioxidant activity. Phytic acid content and phytase activity varied significantly among genotypes and between locations, ranging from 5.9 to 15.1 g/kg and from 1606 to 2154 FTU/kg sample, respectively. Multivariate data analysis performed on 19 components analyzed in this study using principal component analysis (PCA) and cluster analysis demonstrate that differences in seed characteristics, phenolic components, phytic acid, and phytase are major factors in segregating faba bean genotypes. The relatively low phytic acid content and high phytase activity of these low-tannin faba bean genotypes are beneficial/essential traits for their use in human and animal nutrition.     

Increasing root and leaf growth and yield in Mg‐deficient faba beans (Vicia faba) by MgSO4 foliar fertilization

Magnesium (Mg) deficiency reduces yield and quality of crops as Mg is involved in carbohydrate and protein anabolism. Foliar application of MgSO₄ represents a means of ameliorating the nutritional status of crops growing under conditions of deficiency. Foliar Mg application has been demonstrated to increase the chlorophyll concentration and vegetative yield of plants. However, in crop plants used for seed production, the limited number of available studies provides only conflicting results in terms of the efficiency of Mg leaf application on yield and quality. We have examined the effect of increasing Mg foliar application rates on differentially developed leaves and leaf stages with regards to Mg concentration, chlorophyll concentration and biomass formation. Our data reveal that in order to obtain significant effects MgSO₄ concentrations in the spraying solution should be higher than 50 mM, as lower concentrations did not lead to significant changes in the vegetative or generative material. Positive effects of the foliar application on chlorophyll concentration and leaf area were only measured in leaves treated with 200 mM foliar MgSO₄. The application of Mg did not affect the parameters chlorophyll, ion concentration and leaf area in the newly developing leaves, but it had an important influence with regard to yield traits, especially on the formation of pods. The quality of the seeds with regard to the protein concentration was reduced in response to the magnesium deficiency treatment, but the application of foliar magnesium prevented a significant loss of protein.