Bentazon influence on selected metabolic processes of isolated bean leaf cells

Time- and concentration-course studies were conducted to determine the effect of bentazon [3-isopropyl-1H-2,l,3,-benzothiadiazin-4(3H)-one 2,2-dioxide] on photosynthesis, RNA synthesis, protein synthesis, and lipid synthesis using enzymatically isolated leaf cells of red kidney bean (Phaseolus vulgaris L.). Photosynthesis and RNA synthesis were inhibited about 75% at 1 μM bentazon at the 30 min treatment period. This was the lowest concentration and shortest time that significantly inhibited any of these four processes. The degree of inhibition of photosynthesis was greater than the degree of inhibition of RNA synthesis at higher concentrations and/or longer time periods. At 10 μM bentazon, protein synthesis and lipid synthesis were also inhibited. Lipid synthesis was stimulated at 0.1 and 1 μM at 120 min.     

The distribution of taurine in the tissues of some species of insects

Taurine concentration was measured in the tissues of Schistocerca americana gregaria, Blatella orientalis and Tenebrio molitor and was found to be present in all those examined. In the locust Schistocerca gregaria it was found in particularly high concentration in active flight muscle (26 μmol/g) to a lesser extent in the eye (7 μmol/g). The thoracic concentration of taurine in developing locusts showed a strong correlation with the development of flight muscle, increasing from 4.4 to 11.3 μmol/g in the thorax during the first 24 days of adult life. Analysis of the thoracic content of taurine in adults of the three species examined confirmed that high taurine concentrations are associated with fully functional flight muscle. The concentration in the thorax of the flightless flour beetle T. molitor was only 1.79 μmol/g compared to 11.33 μmol/g for the locust. Stress due to flying and picrotoxin poisoning caused the release of taurine from the muscles into the haemolymph, causing the concentration to rise from 1.1 to 2.2 and 5.76 μmol/g respectively. Analysis of the distribution of arginine kinase showed that this release was not due to breakdown of the muscle tissue.     

Comparison of globulin proteins from Phaseolus vulgaris with those from Vicia faba

Extraction of maturing Phaseolus vulgaris seeds with an ascorbic acid—NaCI medium facilitated the preparation of two globulin fractions which wer     

Metabolism of gibberellins in early immature bean seeds

The endogenous free gibberellins in two different stages of immature Phaseolus vulgaris seeds were investigated and GA₁₇, GA₂₀, GA₂₉, a     

Alkaline phytase activity in nonionic detergent extracts of legume seeds

Alkaline phytase activity, with a pH optimum of 8, was recovered from detergent extracts of dormant seeds of nine varieties of Phaseolus vulgaris L., Pisum sativum L. var. Early Alaska, and Medicago sativa L. This alkaline phytase of legume seeds was activated by calcium and differed from most seed phytases in its relative insensitivity to inhibition by fluoride.     

Trigonelline and promotion of cell arrest in G2 of various legumes

Trigonelline, present in dry seeds of Pisum sativum, is transported to enlarging roots and shoots during early seedling ontogeny and promotes cell arrest in G2 in 40% of all root cells. In the absence of trigonelline, this cell population arrests in G1. Results presented herein show that trigonelline also promotes cell arrest in G2 in roots of Glycine max and Phaseolus vulgaris and that the percentage of cells that arrest in G2 in roots of G. max decreases during seedling ontogeny, as it does in P. sativum. During development, trigonelline is synthesized in leaves and is translocated to pods and eventually to seeds during fruit maturation in P. sativum and G. max. Seeds of most legumes have high concentrations of trigonelline and those of some non-legumes have low concentrations.     

Accumulation of 5-ribosyluracil (pseudouridine) within the tissues of Phaseolus vulgaris

Free 5-ribosyluracil (pseudouridine) accumulates within the acid-soluble fraction of germinating seeds and seedlings of Phaseolus vulgaris. Accumulation is significantly increased by erogenous uridine. Experiments with [¹⁴c]-labelled precursors indicate that UTP is an intermediate in the formation of this free 5-ribosyluracil.     

The influence of aluminium availability on phosphate uptake in Phaseolus vulgaris L. and Phaseolus lunatus L.

Aluminium toxicity is one of the major limiting factors of crop productivity on acid soils. High levels of available aluminium in soil may induce phosphorus deficiency in plants. This study investigates the influence of Aluminium (Al) on the phosphate (P_i) uptake of two Phaseolus species, Phaseolus vulgaris L. var. Red Kidney and Phaseolus lunatus L. The two bean species were treated first with solutions of Al at different concentrations (0, 25, 50 and 100 μM, pH 4.50) and second with solutions of P_i (150 μM) at pH 4.50. The higher the Al concentration the higher the Al concentration sorbed but P. vulgaris L var. Red Kidney adsorbed significantly more Al than P. lunatus L. Both species released organic acids: P. vulgaris L var. Red Kidney released fumaric acid and P. lunatus L. fumaric and oxalic acids which could have hindered further Al uptake.The two bean species showed a sigmoid P_i uptake trend but with two different mechanisms. P. vulgaris L var. Red Kidney showed a starting point of 3 h whereas P. lunatus L. adsorbed P_i immediately within the first minutes. In addition, P. vulgaris L var. Red Kidney presented significantly higher P_i uptake (higher uptake rate ‘k’ and higher maximum adsorption ‘a’ of the kinetic uptake model). The Al treatments did not significantly influence P_i uptake. Results suggest that P. lunatus L. might adopt an external Al detoxification mechanism by the release of oxalic acid. P. vulgaris L var. Red Kidney on the other hand seemed to adopt an internal detoxification mechanism even if the Al sorbed is poorly translocated into the shoots. More detailed studies will be necessary to better define Al tolerance and/or resistance of Phaseolus spp.     

Primary Structures of α- and β-Subunits of α-Amylase Inhibitors from Seeds of Three Cultivars of Phaseolus Beans

The primary structures of three α-amylase inhibitors (TAI, DAI, and MAI-2) consisting of glycoprotein subunits α and β from the respective seeds of three cultivars of Phaseolus beans, Toramame (Phaseolus vulgaris L.), Daifukumame (Phaseolus vulgaris L.), and Murasakihanamame (Phaseolus coccineus L.) were determined by sequencing the peptide fragments derived from their enzymatic digestions. Major sugar chains of the inhibitors were also assessed by analyzing glycopeptides in the enzymatic digests. The subunits, α and β, were shown to be composed of 76 and 139 amino acid residues, respectively, in each inhibitor. The overall amino acid sequences of the inhibitors were slightly different from one another. Furthermore, the sequence of TAI was the same as that deduced from a cDNA clone encording α-amylase inhibitor-1 from the common bean (Phaseolus vulgaris L.). It was also revealed that there were two N-glycosylation sites in each α-subunit: PA-derivatives of the major N-glycans were estimated to be M6B at Asn(12) and M9A at Asn(65). Each β-subunit of TAI and MAI-2 had two N-glycosylation sites, while the β-subunit of DAI had only one site. The major N-glycans pyridylaminated were estimated to be M3X at Asn(63) in each β-subunit and M3FX at Asn(83) in β-subunits of TAI and MAI-2.     

Plant species variation in bottom‐up effects across three trophic levels: a test of traits and mechanisms

1. An increasing number of studies have addressed the mechanisms by which plant inter‐specific variation influence interactions at higher trophic levels, but little is known about the underlying plant traits driving these dynamics. 2. Here we investigated the effects of host plant species on herbivore‐parasitoid interactions and the underlying traits driving such effects. For this, we measured the abundance of seed‐eating bruchids and their parasitoids across seven sympatric populations of the bean species Phaseolus coccineus and Phaseolus vulgaris in Central Mexico. To investigate the mechanisms underlying differences between bean species in bruchid‐parasitoid interactions, we carried out two laboratory experiments to test whether bruchid and parasitoid performance differed between plant species. We also measured seed size and phenolic compounds to investigate if seed traits mediate bruchid‐parasitoid interactions by influencing herbivore susceptibility or resistance to parasitoids. 3. Field surveys revealed that the rate of parasitoid recruitment to bruchids was significantly higher on P. vulgaris than on P. coccineus. Subsequent laboratory bioassays indicated that bruchids developed more slowly and exhibited lower fitness on P. vulgaris seeds than on P. coccineus seeds. Accordingly, we found that bean species differed in seed size, with P. vulgaris having smaller (less nutritious) seeds, which explains why bruchid development was slower on this plant species. 4. These results provide a mechanism for why bruchids exhibited higher parasitism rates on seeds of P. vulgaris in the field which could be due to Slow‐Growth/High‐Mortality effects, a smaller physical refuge provided by the seed, or both factors. The roles of these mechanisms remain inconclusive without further study.     

Isolation and Partial Characterization of a Seed Lectin from Tepary Bean that Delays Bruchid Beetle Development

Four isolectin forms of a seed lectin from mature seed of tepary bean (Phaseolus acutifolius) were isolated using solubility fractionation, affinity chromatography, and high performance liquid chromatography. The subunits are polypeptides with an apparent molecular mass of 30,000 daltons. The 30 kilodalton subunits are produced starting approximately 13 days after flowering and subsequently comprise a major fraction of the proteins found in the mature seed. The amino terminus of each isolectin fraction was determined to be highly homologous with that of the subunits of common bean (Phaseolus vulgaris L.) phytohemagglutinin (PHA). The tepary isolectin cross-reacts with both erythroagglutinating and leucoagglutinating subunits of PHA antibodies, although differential cross-reactivity was noted. A seed protein fraction enriched in tepary bean lectin was found to be toxic to bean bruchid beetles (Acanthoscelides obtectus), when incorporated into their diets at incremental concentrations from (1-5% w/w) above that of PHA concentrations in mature seeds of the susceptible common bean variety “Red Kidney.”     

Erythro- and lymphoagglutinins of Phaseolus acutifolius

A potent lymphoagglutinin which had low affinity for red cells or fetuin and another lectin which reacted strongly with red cells and fetuin but was a poor agglutinin for lymphocytes were isolated from seeds of Phaseolus acutifolius. A number of other lectin components with intermediate activity towards these cells was also isolated. All the lectins had very similar amino acid and carbohydrate composition, sedimentation patterns, partial specific volume and molecular weight values of about 116 600 and were thus smaller than the related Phaseolus vulgaris lectins (M_r = 119 000). The lectins contained four subunits with only minor size and charge differences between the lympho- and erythroagglutinating subunits and their electrophoretic mobility in SDS gel electrophoresis was anomalously high. The existence of lympho- and erythroagglutinating subunits in two members of the genus Phaseolus supports their close morphological similarity.     

Mode of Action of the Toxin from Pseudomonas phaseolicola: I. Toxin Specificity, Chlorosis, and Ornithine Accumulation

The specificity of the Pseudomonas phaseolicola toxin for enzyme inhibition and its relationship to toxin-induced chlorosis in bean leaves (Phaseolus vulgaris L.) was examined. The toxin showed no significant inhibitory activity against glutamine synthetase, glutamine transferase, carbamyl phosphate synthetase, aspartate carbamoyltransferase, or arginase at concentrations 100-fold higher than that needed to inhibit ornithine carbamoyltransferase by 50%.     

Suppression of Plant Growth by Nitrogen Dioxide

Nicotiana glutinosa and pinto bean seedlings (Phaseolus vulgaris) were exposed for short periods (3 days or less) to high concentrations of NO₂ (4.11-20.53 mg/m³ to compare the resulting leaf lesions with ozone damage produced at concentrations of 0.43 to 0.86 mg/m³. Although the same physiological age leaf tissue was damaged by both toxicants, damage caused by NO₂ was unlike that caused by ozone.

Pinto bean (Phaseolus vulgaris) and Pearson improved tomato (Lycopersicon esculentum) seedlings were continuously exposed for 10 to 22 days, to low concentrations of NO₂ (less than 1.03 mg/m³). These exposures caused significant growth suppression, increase in green color (total chlorophyll content), and distortion of leaves.

     

Effects of Phaseolus vulgaris (Fabaceae) seed coat on the embryonic and larval development of the cowpea weevil Callosobruchus maculatus (Coleoptera: Bruchidae)

Bruchid beetles infest various seeds. The seed coat is the first protective barrier against bruchid infestation. Although non-host seed coats often impair the oviposition, eclosion and survival of the bruchid Callosobruchus maculatus larvae, morphological and biochemical aspects of this phenomenon remain unclear. Here we show that Phaseolus vulgaris (non-host) seed coat reduced C. maculatus female oviposition about 48%, increased 83% the seed penetration time, reduced larval mass and survival about 62 % and 40 % respectively. Interestingly, we found no visible effect on the major events of insect embryogenesis, namely the formation of the cellular blastoderm, germ band extension/retraction, embryo segmentation, appendage formation and dorsal closure. Larvae fed on P. vulgaris seed coat have greater FITC fluorescence signal in the midgut than in the feces, as opposed to what is observed in control larvae fed on Vigna unguiculata. Cysteine protease, α-amylase and α-glucosidase activities were reduced in larvae fed on P. vulgaris natural seed coat. Taken together, our results suggest that although P. vulgaris seed coat does not interfere with C. maculatus embryonic development, food digestion was clearly compromised, impacting larval fitness (e.g. body mass and survivability).     

Effects of cryopreservation of Phaseolus vulgaris L. seeds on early stages of germination

In this work, we studied the effects of cryopreservation on various parameters of early stages of germination of Phaseolus vulgaris seeds (0, 7 and 14?days). Percentages of germination, fresh mass of different plant parts, levels of chlorophyll pigments (a, b, total), malondialdehyde, other aldehydes, phenolics (cell wall-linked, free, and total) and protein were determined. No phenotypic changes were observed visually in seedlings recovered from cryopreserved seeds. However, several significant effects of seed liquid nitrogen exposure were recorded at the biochemical level. There was a significant negative effect of cryopreservation on shoot protein content, which decreased from 3.11?mg?g^?1 fresh weight for non-cryopreserved controls to 0.44?mg?g^?1 fresh shoot weight for cryopreserved seeds. On the other hand, cryopreservation significantly increased levels of other aldehydes than malondialdehyde in shoots at day 7, from 56.47?μmol?g^?1 for non-cryopreserved controls to 253.19?μmol?g^?1 fresh shoot weight for cryopreserved samples. Liquid nitrogen exposure significantly reduced phenolics contents (free, cell-wall linked, total) in roots at day 7 after onset of germination. In general, roots were more affected by cryostorage compared with other plant parts, while leaves were the least affected. The effects of seed cryopreservation seem to decline progressively along with seedling growth.     

Protein Synthesis During Rehydration, Germination and Seedling Growth of Naturally and Precociously Matured Soybean Seeds (Glycine max)

p. 86, line 6, should read: These patterns of soluble protein synthese are similar to thoseobserved after precocious maturation and subsequent rehydrationof castor bean (Kermode and Bewley, 1985a, b, 1986), and withinaxes of Phaseolus vulgaris L. seeds (Dasgupta and Bewley, 1982). instead of: These pattern of protein synthesis. Unlike castor bean thoseobserved after precocious maturation and subsequent rehydrationof castor bean (Kermode and Bewley, 1985a, b, 1986), and withinaxes of Phaseolus vulgaris L. seeds (Dasgupta and Bewley, 1982).     

Purification and partial characterization of a gibberellin 2β-hydroxylase fromPhaseolus vulgaris

A gibberellin 2β-hydroxylase has been purified from mature seeds ofPhaseolus vulgaris. The enzyme is of molecular weight 36,000 and has the characteristics of a dioxygenase; the cofactors areα-ketoglu-tarate, Fe²⁺ and ascorbate, and activity is stimulated by catalase. The V_max of the enzyme is 6.86 nmole h^?1 mg^?1, and the Km values for [1,2-³H₂]GA₁ andα-ketoglutarate are 0.085 μM and 21 μM, respectively. The purified enzyme preparation catalyzes hydroxylation of GA₁, GA₄, GA₉, and GA₂₀ but exhibits a marked preference for the 3-hydroxylated gibberellins as substrate.     

Dimethylallylpyrophosphate:3,9-dihydroxypterocarpan 10-dimethylallyl transferase from Phaseolus vulgaris Identification of the reaction product and properties of the enzyme

A microsomal fraction of elicitor-challenged bean (Phaseolus vulgaris) cell suspension cultures catalyses the prenylation of 3,9-dihydroxypterocarpan (DHP) to 3,9-dihydroxy-10-dimethylallylpterocarpan (phaseollidin) with dimethylallylpyrophosphate (DMAPP) as the prenyl donor. K_m values for DMAPP and DHP are in the range 1–3 μM. Strong product inhibition with phaseollidin and phaseollin is observed.     

Desert species adapted for dispersal and germination during floods: Experimental evidence in two Astrophytum species (Cactaceae)

Dispersal of organisms by water is known as hydrochory and is an important means of seed transportation. Here we present experimental evidence of possible dispersal and germination of seeds in water for arid land cacti. Seeds from Astrophytum spp. have unusual traits for plants from arid environments, traits that are typical of water dispersed seeds. Astrophytum capricorne and A. ornatum seeds disperse by floating in the Chihuahuan Desert. Seeds of other native species (Acacia farnesiana, Opuntia streptacantha and Prosopis laevigata (mesquite) were used as control, as well as commercial beans (Phaseolus vulgaris). Seed structures of A. capricorne and A. ornatum are consistent with water dispersal (hat shape, a funicular envelope covering a prominent hilum, and air chambers throughout the tegument). Seeds of A. capricorne showed the greatest water permeability, higher than those of A. ornatum which had similar permeability to common beans and mesquite. Acacia farnesiana and Opuntia streptacantha had the lowest permeability. Seeds of A. capricorne without a funicular layer floated more than those with a funicular layer. All seeds of A. ornatum floated initially, but 10% of those with funicular layer sank after a 30 days floating period. P. laevigata seeds floated also, but less than those of Astrophytum spp., and seeds of A. farnesiana and Phaseolus vulgaris did not float. Germination of A. capricorne was high under all treatments, both when immersed in a water layer or only moistened. Germination of A. ornatum was generally low (<30%), with <5% germination for seeds immersed in water and for those placed on a water film. Seeds of A. capricorne germinated slower in a water layer than in other treatments. No difference in germination rate was found across all treatments in A. ornatum.