豇豆CAT活性的研究

[目的]对豇豆过氧化氢酶（CAT）的活性进行研究。[方法]以豇豆中的过氧化氢酶为材料,测定其活力、最适温度与pH值,及各因素对活力的影响。[结果]豇豆中过氧化氢酶的最适pH值为8.0,最适温度为25℃。甲醇和乙醇对豇豆中过氧化氢酶活性的影响均表现为低浓度具有激活作用,高浓度转为抑制作用。金属离子Cu2＋对该酶有不用程度的激活作用,而Mg2＋和Na＋则对该酶有一定程度的抑制作用。[结论]该研究为豇豆过氧化氢酶的进一步研究提供了理论依据。     

Differential expression of defence-related proteins in Vigna unguiculata (L. Walp.) seedlings after infection with Fusarium oxysporum

This work aimed to study the induction of defence proteins in cowpea seedlings during the first days after infection with the fungi Fusarium oxysporum f. sp. cubenses and F. oxysporum f. sp. phaseoli. Cowpea seeds, after disinfection, were transferred to Petri dishes containing 0.5% agar and, after germination, were infected with a drop of a suspension containing 0.5 × 10⁴ spores ml⁻¹. Seedlings were collected at 24, 48, 72 and 96 h after infection and were dissected into leaves, hypocotyls, roots, cotyledons and teguments, which were measured and weighed for morphometric analysis. The agar medium was also analyzed. Enzymatic assays of proteic extracts yielded antimicrobial peptides detected by Western blotting. The cowpea seedlings showed a complex pattern of induction and repression of defence proteins in response to infection by both pathogens. Furthermore, morphometric analysis showed differences between infected and control seedlings. Infected samples did not at any time exhibit chitinase activity, but did exhibit different β-1,3-glucanase and peroxidase activities. Western blotting for lipid transfer protein (LTP) demonstrated its presence in all parts of the infected seedlings. Exuded proteins, also obtained from cowpea seeds in the germination medium, were separated by SDS-PAGE and tricine gel electrophoresis. The analysis showed that some proteins were exuded from moistened cowpea seeds, particularly after F. oxysporum infection.     

A Review on Regeneration in Cowpea （Vigna unguiculata L. Walp）

Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.     

小豆根瘤菌接种结瘤条件分析

设计不同的小豆根瘤菌及菌液浓度、侵染时间和接种方式接种小豆推广品种京农5号和京农6号,研究其对小豆结瘤数的影响。根瘤菌BAU73042菌液浓度0.6 OD接种,单株平均结瘤数最多;BAU11017菌株菌液浓度0.2 OD接种,单株平均结瘤数最多。BAU73042侵染京农6号15 min单株结瘤数最多,BAU11017侵染京农5号45 min单株结瘤数最多。菌液浇灌接种方式优于菌液侵染接种;不同品种接种不同根瘤菌的结瘤反应不同。该研究为小豆固氮研究及利用和根瘤突变体筛选鉴定奠定了基础。     

Epidemiological studies on powdery mildew of mungbean and urdbean

Abstract

Powdery mildew of mungbean (Vigna radiata L. Wilczek) and urdbean ( V. mungo L. Hepper) caused by Erysiphe polyponi DC during the winter/spring season is a severe constraint in the production of bean crops in the Chhattisgarh region of Madhya Pradesh. Keeping this in view, studies were made to understand the development of powdery mildew in relation to crops, varieties, weather conditions and their effect on yield. The first appearance of powdery mildew in 33 mungbean and 18 urdbean varieties was 1 week earlier during winter 1992–93 than winter 1991–92. Its development was most rapid each year when the average maximum temperature varied from 27.2 to 30.3°C, relative humidity from 67 to 90% during the morning and 12 to 38% at noon, and wind velocity from 2.3 to 4.1 km/h. A positive correlation occurred between mildew severity and temperatures and wind velocity in most of the varieties. However, the correlation with relative humidity was negative and significant except in a few varieties. The pooled infection rates (r)/unit/day on resistant mungbean and urdbean varieties was less than 0.1 with disease scores of 1–5 while in apparently slow mildewing varieties, rvalues were also less than 0.1 but showed a score of 7–9. The effect of disease levels on grain yield of urdbean had a negative and significant correlation. However, it was negative but not significant in the case of mungbean. Grain yield was considerably higher when the crops were protected with one spray of Bavistin (1 kg/ha in 5001 of water) followed by Sulfex (3 kg/ha in 5001 of water) than in the untreated control. The disease scores in sprayed plots were also markedly less and ranged between 0 and 5 as against 1 and 9 in the untreated control in different varieties.     

Mapping of QTLs controlling epicotyl length in adzuki bean (Vigna angularis)

Epicotyl length (ECL) of adzuki bean (Vigna angularis) affects the efficiency of mechanized weeding and harvest. The present study investigated the genetic factors controlling ECL. An F₂ population derived from a cross between the breeding line ‘Tokei1121’ (T1121, long epicotyls) and the cultivar ‘Erimo167’ (common epicotyls) was phenotyped for ECL and genotyped using simple sequence repeats (SSRs) and single-nucleotide polymorphism (SNP) markers. A molecular linkage map was generated and fifty-two segregating markers, including 27 SSRs and 25 SNPs, were located on seven linkage groups (LGs) at a LOD threshold value of 3.0. Four quantitative trait loci (QTLs) for ECL, with LOD scores of 4.0, 3.4, 4.8 and 6.4, were identified on LGs 2, 4, 7 and 10, respectively; together, these four QTLs accounted for 49.3% of the phenotypic variance. The segregation patterns observed in F₅ residual heterozygous lines at qECL10 revealed that a single recessive gene derived from T1121 contributed to the longer ECL phenotype. Using five insertion and deletion markers, this gene was fine mapped to a ~255 kb region near the end of LG10. These findings will facilitate marker-assisted selection for breeding in the adzuki bean and contribute to an understanding of the mechanisms associated with epicotyl elongation.     

Fiber‐optic spectrophotometry of cowpea nodules treated with nitrate or ammonium

Abstract

Cowpea nodules (Vigna unguiculata [L.] Walp. cv. CB5) were pierced with two opposing optical fibers (280 μm diameter), and absorbance spectra of 0.1 mm of nodule tissue were recorded from 415 to 600 nm using a modified spectrophotometer with a nodule sampling stage.

The nodule spectra exhibited two absorbance bands, a major band in the near‐UV (415–450 nm) and a lesser one in the green‐yellow region (510–585 nm); the latter exhibited a prominent peak at 550 nm. Nodule spectra were consistent with the superposition of the spectra of ferroleghemoglobin (Lb²⁺), oxyleghemoglobin (Lb²⁺‐ O₂), and cytochrome c (550 nm). The detection of leghemoglobin in vivo was confirmed by demonstrating the reversibility of binding of CO to Lb, and by comparing the spectra of live nodules with those obtained from anaerobic leghemoglobin preparations.

The effects on the nodule spectra of two successive applications (36 and 39 days after planting) of 5 and 10 mM NO₃ ^‐ or NH₄ ⁺ to the nutrient solution bathing the nodulated roots were determined. The spectra of NO₃ ^‐‐ and NH₄ ⁺‐treated nodules were indistinguishable; in each case the height of both the near‐UV and green‐yellow absorbance bands decreased with treatment. Treatment with N caused a significant reduction in the area of the green‐yellow absorbance band.

The spectra of green leghemoglobin pigments were obtained from senescent nodules; these exhibited a reduction in the height of the near‐UV absorbance band and a flattening of the green‐yellow band similar to that of nodules treated with N, but the broadening of the near‐UV band was greater in green nodules.     

Resistance to the legume pod borer, Maruca vitrata Fabricius, and the probable modalities involved in wild Vigna

A large number of accessions belonging to selected wild Vigna species namely V. unguiculata subspecies dekindtiana, V. oblongifolia, and V. vexillata were evaluated using choice (DCAT) and no-choice (NCFT) laboratory feeding bioassays to determine their resistance to the pod borer, Maruca vitrata Fabricius. The most resistant accessions belonged to V. vexillata, followed by those from V. oblongifolia, with a few outstanding exceptions from V. unguiculata. Even though the latter were the least resistant, they provided the greatest variability among the tested accessions. In the DCAT, the cultivated cowpea line, IT84S-2246, which was used as the susceptible control was always preferred for feeding by the larvae (feeding index [FI] of 1.10–2.60) than the V. unguiculata accessions (FI ranged from 0–0.52). Against the resistant control (itself belonging to V. vexillata), only a few accessions were less preferred, most of these being either V. vexillata or V. oblongifolia. Larvae lost weight on the most resistant from all three species, because they either did not feed, or fed very little. Weight gain was positively correlated with seed damage (r = 0.82, P < 0.01) and the amount of frass produced (r = 0.91, P < 0.01). Seed damage was also positively correlated with the amount of frass produced (r = 0.64, P < 0.05). On the basis of these results, we believe that both antibiosis (post-ingestive effects) and antixenosis (deterrence to boring into the pods to feed) modalities of resistance are involved. The results are discussed further in relation to the origin, domestication and use of these accessions in cowpea improvement.     

海水胁迫下海带提取物对豇豆发育的影响

[目的]探讨海水胁迫下海带甲醇提取物对豇豆的生长效应。[方法]将海水稀释成7种浓度梯度液培养豇豆种子,用25%海水将海带甲醇提取物分别稀释50、200、800和1200倍后培养豇豆种子,10 d后测定幼苗的各项生长指标。[结果]豇豆成苗率随着海水浓度的增加而下降,25%海水的成苗率为22.22%,确定海水的临界浓度为25%。海带甲醇提取物200倍液对豇豆成苗率的提高最明显,比对照提高64.71%。该提取物50倍液对豇豆的生长效果优于其他浓度,其主根长、总鲜重、根鲜重、叶鲜重、叶绿素a与b含量和叶绿素总量分别比对照提高了23.08%、18.27%、31.89%、44.87%、1.29%、1.43%和1.79%。[结论]在25%海水胁迫下海带甲醇提取物对豇豆幼苗生长具有较明显的作用。     

小豆生长发育规律研究 Ⅹ．小豆群体干物质生产与产量形成的关系

以JN2、JN5、JN6、JN7等4个不同粒型的红小豆品种为材料,研究了小豆群体干物质生产与产量形成的关系。结果表明:(1)夏播小豆的群体生产量变化表现为前期增长慢,从8月中旬开始快速增长。(2) JN2、JN5、JN6、JN7在开花期最适宜的干物重积累量分别为368．64、339．66、354．72和406．08 kg/hm2,生育后期干物质积累JN2为6 241．36 kg/hm2时产量最高,而其他3个品种后期累积量在4 000 kg/hm2左右即可达到预期目标。(3)开花期的叶面积指数,JN2应控制在6-7之间,JN6控制在4-6之间,JN5控制在4左右, JN7控制在3左右为最适,产量较高。(4)在中等肥力大田生产条件下,JN2适宜高密度(36万株/hm2)种植, JN5和JN7适宜中低密度(18万株/hm2)种植,JN6适宜中高密度(24万株/hm2)种植。