Mature de-embryonated cotyledons with intact proximal end of Vigna unguiculata were cultured on B5 basal medium containing varying concentrations of BAP. Thirty-six percent of the explants produced shoots on B5 medium supplemented with 8× 10(-6) M BAP. Cotyledon explants were pre-incubated for 24 h, inoculated with A. tumefaciens pUCD2614 carrying pUCD2340, co-cultivated for 48 h and transferred to hygromycin-B (25 mg/l) containing shoot induction medium. Approximately 15-19% of the explants produced shoots on the selection medium. The elongated shoots were subsequently rooted on B5 basal medium containing hygromycin. The transgenic plants were later established in pots. The presence of hpt gene in the transgenic plants was confirmed by Southern blot hybridization.

Photosynthetic properties of cell suspension cultures derived from the callus proliferation of eladophyll explants of Chamaecereus sylvestrii Spegazzini were studied. High content of chlorophyll (105-120 [xg/g fresh weight), cyanide sensitive Oi uptake and maximal rates of O, evolution (100-115 ^mol/mg Chi X h) and COj fixation (13()-150 nmol/mg Chi x h) were some of the properties of the exponential phase cells. Determination of the component reactions, viz. photosystems I and II and photophosphoryiation of the chloroplasts isolated from the cells, indicated normal development and functioning of the photosynthetie machinery.Studies on the enzymatic reactions as well as the determination of the early produets of "CO2 fixation in light in these eells implicated the operation of both autotrophic and non-autotrophic pathways, the latter being less pronounced. The diurnal oscillation of titratable acidity and malate content found in the intact eladophyll tissues was absent in the cultured cells. Evidences for a rapid and continuous drain of carbon from malate into the citrate and isocitrate components of the TCA cycle via pyruvate after decarboxylation, and then into the amino acid pool are presented. The absence of large vacuoles and the rapid turnover of malate are considered to account for the lack of diurnal fluctuation of organic acide in the cell cultures.

No abstract

Plants were regenerated from the in vitro cultured explants of primary leaves of cowpea (Vigna unguiculata L.

Materials and MethodsThe plant materials used in this study included cultivated and weed plants grown in the botanic garden under normal conditions. Althouigh several plant species have been found useful for cell isolation only the leaves from the cultivated plants of Dolichos lab lab var. Lignosis Prain (Bean) were used extensively for photosynthetic and other metabolic studies. Ten grams of fresh leaves were chilled and ground in a smooth surfaced porcelain pestle and mortar with 40 ml of grinding media containinig sucrose 400 ,umoles, MgCl, 10 ,Amoles, tris-HCl buffer 20 ,umoles pH 7.8. The homogenate was filtered through 2 layers of fine muslin cloth to separate the large debris. The filtrate was centrifuged at 200g for 30 sec. The supernatant was slowly decanted, discarding the pellet which essentially contained large aggregates of mesophyll cells.