Rhizobacterial bioformulation for the effective management of Macrophomina root rot in mungbean

Abstract

Fluorescent pseudomonads based bioformulation was evaluated for their ability to control Macrophomina root rot disease in mungbean (Vigna mungo). P. fluorescens isolate Pf1 showed the maximum inhibition in mycelial growth of Macrophomina phaseolina under in vitro conditions. Bioformulation of Pf1 with chitin was effective in reducing the root rot incidence in green gram both under glasshouse and field conditions. The rhizosphere colonization of P. fluorescens was observed appreciable with the green gram plants. However, Pf1 amended with chitin colonized effectively. Furthermore, the induction of defence-related enzymes and chemicals in plants by Pf1 amended with or without chitin and neem were tested. Increased accumulation of defence enzymes viz., phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenol oxidase (PPO), chitinase, β-1,3-glucanse and phenolics were observed in Pf1 bioformulation amended with chitin, pre-treated plants challenge inoculated with M. phaseolina under glasshouse conditions. The present study reveals that in addition to direct antagonism and plant-growth promotion, PGPR strains amended with chitin bioformulation induced defence-related enzymes and pathogenesis related (PR) proteins which collectively enhance the resistance in green gram against the infection of M. phaseolina.     

Effect of VAM inoculum carry-over on the successive cropping of maize and mungbean

A field study to determine the endomycorrhizal inoculum carry-over effect of the first crop [maize inoculated with Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe] on the succeeding crop (mungbean) was carried out in fumigated and nonfumigated acidic soil (pH 5.3) with moderate extractable P (Olsen 23 ppm). G. mosseae inoculation increased maize dry matter and grain yield over the uninoculated control in the nonfumigated soil. The maize inoculation failed to carry the effective inoculum over to the mungbean crop planted immediately after maize harvest and thus did not increase root colonization and grain yield of the succeeding crop. Fresh inoculation of the mungbean with G. mosseae increased grain yield over the uninoculated control.     

Quinones as plant growth regulators

The effects of benzoquinone, naphthaquinone and anthraquinone on the growth of tomato callus, whole plants of tomato and on rooting of mungbean cuttings were studied. Naphthaquinone effects on some oxidases and on the isozyme patterns of peroxidases in all the three systems were also observed. Quinones increased callus growth, the number of roots initiated in mungbean cuttings and the growth of tomato plants, significant increases being obtained with 10^–5 M naphthaquinone. Naththaquinone also decreased the activities of IAA oxidase, ascorbic acid oxidase and polyphenol oxidase, and led to the disappearance of one of the isozyme of peroxidase in all systems.     

嫁接导致的绿豆可遗传性变异及其在绿豆育种中的应用

植物嫁接可以导致接穗的后代中有可遗传性变异的发生。我们将绿豆 (Vignaradiata (L .)Wilczek)的幼苗嫁接在红薯 (Ipomoeabatatas (L .)Lam .)的茎上 ,维护其生长至结实。将收获的绿豆种子连续几代播种于普通环境时 ,其后代中出现了明显的遗传变异。这些变异在未经嫁接的绿豆接穗品系中并不出现。为了研究这种嫁接诱导变异现象可能的机理 ,我们对变异品系的细胞质和细胞核DNA进行了分析。结果显示 ,在原绿豆和变异品系之间未发现细胞质DNA的RFLP(限制性酶切片段多态性 )差异。而细胞核DNA却发生了高频率的序列重组。同时 ,本研究没有发现砧木与接穗间基因转移的迹象。根据以上事实 ,我们推测远缘嫁接变异很有可能是嫁接生长逆境诱导的抗逆变异。     

Purification and characterization of Cu-Zn superoxide dismutases from mungbean (Vigna radiata) seedlings

Mungbean contains three isoenzymes of superoxide dismutase designated isoenzyme I, II and III. The two cytosolic superoxide dismutases (I and II) were purified to homogeneity by ammonium sulphate fractionation, ion exchange chromatography on diethylaminoethyl cellulose, gel filtration and preparative polyacrylamide.gel electrophoresis. The molecular weights of isoenzyme I and isoenzyme II were determined to be 33,000 and 31,600 respectively. The subunit molecular weight was approximately 16,000 indicating that the isoenzymes contained two identical subunits. The ultra-violet absorption spectra revealed a maximum at 258–264 nm for the two isoenzymes. Superoxide dismutase I and II were inhibited to different extents by metal chelators. Isoenzyme I was more sensitive to inhibition by cyanide and azide, while isoenzyme II was more susceptible to inhibition by diethyldithiocarbamate ando-phenanthroline. Both the isoenzymes exhibited similar denaturation profiles with heat, guanidinium chloride and urea. The denaturation with urea and guanidinium chloride was reversible. The two copper-zinc enzymes were more stable towards thermal inactivation compared to manganese and iron superoxide dismutases from other sources. The results indicate that the two isoenzymes differ from each other only with respect to charge and sensitivity towards metal chelators.     

Effect of Substrate Moisture and Potassium on Water Relations and C, N and K Distribution in Vigna Radiata

The Vigna radiata L. plants were grown in greenhouse at moisture content of sand (SMC) of 12.0 ± 0.5 %. At flower bud initiation stage, i.e. 45 - 50 d after sowing, the SMC was decreased to 3.5 ± 0.5 %, and the effects of applied potassium (0, 2.56 and 3.84 mmol dm-3) were studied. During water stress, K-fed plants maintained higher leaf water potential and relative water content (RWC) of leaves and nodules and lower osmotic potential as compared to untreated plants. The proline content was higher in nodules than in leaves showing their difference in degree of stress. A partial recovery was found after re-irrigation. When subjected to drought, carbon was accumulated in the leaves and declined in nodules and roots. K-fed plants showed higher C and N content in stem, roots and nodules than untreated plants. The content of K significantly increased in stem and nodules in K-fed plants, irrespective of SMC. Dry masses of different plant parts were also increased in K-fed plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Diversity in greengram (Vigna radiata (L.) Wilczek) germplasm collection and its potential use in crop improvement

Greengram or mungbean (Vigna radiata (L.) Wilczek), which originated in the Indian sub-continent, is an important pulse crop in India. Genetic diversity and patterns of variation among 111 accessions representing the better agronomic types from the entire collection of the National Bureau of Plant Genetic Resources were studied. Wide variation in morphological and agronomic traits viz. number of pods per plant, yield per plant, 100-seed weight, fruit setting capacity, flowering period, maturity, number of pod bearing peduncles, plant height, number of primary branches, length of branch, nodulation and leafiness was observed. Grain yield was found to be significantly correlated with 100-seed weight and pod length. The data were subjected to cluster and principal components analysis. The accessions were grouped into six discrete and well-defined clusters. The study demonstrated the patterns of variation at the population level. The multivariate analysis was useful in identifying a group of accessions with yield enhancing traits within a highly diverse group of accessions and their potential value in greengram improvement is suggested.     

Effect of far infrared rays emitted from the calcined ceramics on ethylene production in mungbean hypocotyls

Ethylene production was measured in mungbean hypocotyls in the presence of far infrared rays emitted from ceramic powder using a gas chromatography. Both IAA-and 1-aminocyclopropane-1-carboxylic acid (ACC)-induced ethylene production was inhibited by 20–30% of the control by indirect application of the ceramic powder. These data suggested that far infrared rays emitted from ceramic powder might act on the conversion step of ACC to ethylene. Furthermore, the activity of ACC oxidase, acting on the conversion of ACC to ethylene, was also inhibited by 20% of the control by indirect treatment of the ceramic powder. These results suggested the possibility that inhibition of ethylene production by far infrared rays emitted from ceramic powder could be used for increasing the period of storage and freshness of crops, fruits, and vegetables.     

黄土区农林复合生态系统中大豆和绿豆的光合生理特性

用Li-6400光合测定系统和FMS-2.02荧光仪测定了单作及间作农林复合系统中大豆和绿豆的光合荧光参数日变化特征,进一步解析复合系统光能竞争机理.结果表明:(1)从单作到间距核桃1 m间作模式,距核桃树越近,遮光愈多,各处理大豆、绿豆的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)表现出与光合有效辐射(PAR)基本一致的先升后降的日变化模式.(2)随着遮荫程度的提高,大豆、绿豆叶绿素含量和表观量子效率(Ф)升高,而光饱和点(LSP)和光补偿点(LCP)降低.(3)随着遮荫程度的提高,大豆、绿豆叶绿素荧光参数最大光能转换效率(Fv/Fm)、PSⅡ电子传递量子效率(ФPSⅡ)以及光化学猝灭系数(qP)均有不同程度的升高,而非光化学猝灭系数(qN)却逐渐降低.研究发现,大豆和绿豆能适应间作系统的弱光环境,在较低的光照条件下正常生长,植物的光合特性与其生境特点相符.     

渗透胁迫对绿豆叶圆片叶绿素荧光的影响

绿豆叶圆片用0、-0．3、-0．6、-1．2、-1．8、-2．4MPa等6个渗透梯度处理24h后,其叶绿素荧光的反应表明：光系统Ⅱ的潜在量子产量(FD／Fm)和电子传递受体(QA)的库容(pool size)均随胁迫强度的增大而减小,但QA库容的下降明显比Fg／Fm的下降缓和。结合原初荧光Fo和最大荧光Fm的变化,分析认为本实验中渗透胁迫并未导致明显的光系统Ⅱ反应中心的失活或破坏。造成光系统Ⅱ潜在量子效率降低的原因主要是通过光系统Ⅱ反应中心到Ⅱ的电子传递受到阻抑。