Search Results
Abstract
Adventitious roots in mung bean [Vigna radiata (L.) R. Wilcz. cv. Berken] cuttings develop from specific “rooting-zone parenchyma” (R-ZP) cells. Microautoradiography was used to determine the timing of thymidine and uridine incorporation into the R-ZP cells, prior to the first cell division, in the presence or absence of naphthaleneacetic acid (NAA). Since 6-3H-thymidine incorporation reached a maximum between 11 and 14 hours, we suggest that the R-ZP cells were in the G1 phase when the cuttings were taken. Tritiated uridine was incorporated into the RNA of the R-ZP cells 2 hours after the cuttings were placed in the labeled solution. DNA synthesis and cell division of the R-ZP cells occurred along the entire length of the hypocotyl (basal, middle, and top segments), but these initial events were not sufficient to result in the subsequent formation of adventitious roots. NAA promoted adventitious root formation in the cuttings but it had no apparent effect on nucleic acid labeling nor initial cell division of the R-ZP cells. The initial division of the R-ZP cells appears to be a wounding response and occurs in the presence or absence of exogenous auxin.
Abstract
Interspecific hybridization between Vigna radiata and V. angularis is reported for the first time. Two hybrids developed from embryos which were excised from immature seeds of V. radiata and cultured on artificial medium. The plants flowered early and continuously until death. No seeds were produced. Mean pairing at metaphase I was 2.39II + 17.22I (2n = 22).
Abstract
Ethylene liberated from control and auxin-treated cuttings of Vigna radiata (L.) R. Wilcz cv. Berken was monitored for 14 hours. For root initiation, naphthaleneacetic acid (NAA) and indolebutyric acid (IBA) were the most effective with indoleacetic acid (IAA) intermediate and 2,4-dichlorophenoxyacetic (2,4-D) the least effective. No correlation was observed between the quantity of auxin-induced ethylene evolved and the number of roots formed. Decreasing the NAA solution pH from 7.0 to 3.0 reduced the evolution of ethylene but did not alter the rooting response of the cuttings. It was concluded that stimulation of adventitious root initiation by auxin is not mediated by ethylene.
Abstract
Adventitious root initiation decreased in ‘Berken’ mung bean cuttings treated with ≥ 10−4 m (2-chloroethyl) phosphonic acid (ethephon). Ethephon at 10−3 but not 10−5 m reduced root length and caused a redistribution of roots along the hypocotyl. The application of ethephon in combination with indoleacetic acid (IAA), indolebutyric acid (IBA), naphthaleneacetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D) reduced root initiation. An initial treatment of ethephon followed by NAA, or NAA followed by ethephon, inhibited root initiation to the same degree. Ethephon—whether applied at the time of cutting preparation or up to 12 hours later—inhibited root initiation to the same extent.
Seeds of `Berken' mung bean [Vigna radiata (L.) R. Wilcz.] were surface-sterilized with NaOCl and then either aerated 24 hours before sowing (routine procedure), planted immediately after the NaOCl treatment, or treated with hot cupric acetate and antibiotics before planting. Nine- or 10-day-old seedlings were used in rooting bioassays. Up to 10% of the seedlings and 17% of the cuttings had collapsed upper stems or wilted leaves. None of the seed treatments completely eliminated the pathogen, but the combination of hot cupric acetate plus antibiotics reduced the quantity of diseased cuttings to 3.3%. A white and two yellow-pigmented (Y1 and Y2) bacteria were isolated from diseased cuttings and used in subsequent pathogenicity tests. The Y2 strain was nonpathogenic. Stems of plants inoculated with the white strain turned brown and collapsed 2 days after inoculation, whereas leaves of plants inoculated with the Y1 strain wilted after 7 days. Electron microscopy, fatty acid analysis, and standard biochemical and physiological tests were used to identify the white strain as Pseudomonas syringae pv. syringae van Hall and the Y1 strain as Curtobacterium flaccumfaciens ssp. flaccumfaciens (Hedges) Collins and Jones. These results emphasize that seeds of mung bean should be checked for seedborne pathogens to avoid experimental artifacts.
Abstract
The performance of the mung bean cultivar Thai Green Oil was compared with the soybean cutivar Hsih-Hsih over a range of 12 plant densities from 10,000 to 800,000 plants/ha. Increasing plant density was positively related to yield and plant height and negatively related with significant reductions in flowering, yield per plant and plant branching. The higher yield potential of soybeans at high plant densities, relative to mung bean, was attributed to differences in the production of the number of flowers per plant and, subsequently, the number of pods per plant. This relationship can be applied to breeding and selecting improved mung bean cultivars.
Abstract
Methanolic extracts from leaves, young stems, and old stems of five Acer (maple) spp. were tested for their effects on adventitious root initiation in mung bean (Vigna radiata Wilcox’) cuttings. An extract from the leaves of A. ginnala strongly stimulated root initiation, and the active compounds in this fraction were not synergistic with IAA. This extract was more stimulatory than IAA on mung bean cuttings and stimulated root initiation in softwood cuttings of A. saccharinum and A. griseum. Preliminary characterization of this extract indicates that it is a phenolic compound and/or a weak acid. Chemical name used: 1H-indoIe-3-acetic acid (IAA).
Abstract
Selected putative inhibitors of ribonucleic acid (RNA) synthesis (actinomycin D and 6-methylpurine) or protein synthesis (cycloheximide and puromycin) were examined for their effects on root formation in mung bean (Vigna radiata (L.) R. Wilcz.) cuttings in the presence or absence of naphthaleneacetic acid (NAA). Only 6-methylpurine completely inhibited root formation at concentrations that did not cause visible injury. Cycloheximide was most inhibitory when applied at the same time as NAA. Application of 6-methylpurine up to 12 hours after NAA uptake completely blocked root formation; thereafter its effect declined with time. This decline in response was correlated with enlargement of the nucleus and nucleolus in hypocotyl cells preparatory to cell division.
Abstract
The mean rate of deterioration of green gram mung bean (Vigna radiata [L.] R. Wilcz.) sprouts stored at 0, 2.5, 5 or 10°C increased linearly with temperature. The sprouts reached the lower limit of salability in about 8.5, 5.5, 4.5 and 2.5 days at the respective temperatures. There was no symptom of chilling injury. The rates of CO2 production were 23, 29, 42 and 96 mg/kg— hr, at 0, 2.5, 5 and 10°, respectively, when measured 1 day after the sprouts were harvested. The corresponding rates of ethylene production were 0.15, 0.05, 0.24 and 0.90 μl/kg-hr.
The effectiveness of using moving mean covariance analysis (MMCA) rather than randomized complete-block design (RCBD) in experimental error control was compared in a large-scale mungbean [Vigna radiata (L.) Wilczek] yield trial. The MMCA was superior to the RCBD, since it significantly reduced the experimental error and the coefficient of variation (cv). Inclusion of five neighboring plots in the moving mean computation provided better error control. However, the estimation of optimum number of neighboring plots to be used and moving mean calculations were tedious. The feasibility of using border-row measurements such as mean plant height at 50% flowering or mean seed yield/m of row as a covariate in an analysis of covariance (BRMCA) was examined in a separate mungbean yield trial in which border rows were planted with a check cultivar. Both border-row measurements were equally effective in reducing the experimental error. However, plant height measurements were simpler than measuring seed yield. Because border-row measurements could be readily used as covariate in analysis of covariance without a need for moving mean computation from the response variable, BRMCA could be advantageous for error control in row crops yield evaluation.