Twigs of Salix species are candidates for cryopreservation procedures because they become tolerant of freezing temperatures during mid-winter. We examined several variables in developing a two-step cryopreservation procedure for sections from these twigs. Samples of Salix triandra cooled to -30 or -35 degree C and then transferred to the vapor phase over liquid nitrogen gave the greatest percen...

two separate factorial experiments were conducted to study the effects of explant sources, plant growth regulators, sucrose concentrations, and light conditions on in vitro cormlet formation of freesia (freesia ×hybrida bailey 'argenta'). interestingly, it was observed that the pupae had lower contamination levels compared to mother corms. using 40% sodium hypochlorite solution for 40 min, cont...

two separate factorial experiments were conducted to study the effects of explant sources, plant growth regulators, sucrose concentrations, and light conditions on in vitro cormlet formation of freesia (freesia ×hybrida bailey 'argenta'). interestingly, it was observed that the pupae had lower contamination levels compared to mother corms. using 40% sodium hypochlorite solution for 40...

Functional screening of an Arabidopsis cDNA library enabled the identification of a novel cDNA, ESR1 (for Enhancer of Shoot Regeneration), that can confer cytokinin-independent shoot formation when overexpressed in Arabidopsis root explants. Neither callus induction nor root formation was affected by ESR1 overexpression. ESR1 encodes a putative transcription factor with an AP2/EREBP domain. Sur...

Canaline and canavanine (inhibitors of polyamine biosynthesis) effects on root and shoot formation were determined in vitro for etiolated hypocotyl segments of leafy spurge (Euphorbia esula L.). Canaline (an ornithine analogue) at 10 to 100 μmol/L inhibited root and shoot formation. The simultaneous application of putrescine did not reverse canaline-induced inhibition of root formation. Ornithi...

The shoot apical meristem of higher plants is a self-maintaining stem cell system which gives rise to the entire above-ground part of a plant. In the past year, genetic and molecular studies have provided increasing insight into the processes of shoot meristem formation and maintenance, as well as into the relation between the apical meristem and its products.

De novo shoot regeneration is widely used in fundamental studies and agricultural applications. Actin microfilaments are involved in many aspects of plant cell division, cell morphogenesis and cell signal transduction. However, the function of actin microfilaments during de novo shoot regeneration is poorly understood. Here, we investigated the organization of actin microfilaments during this p...

Plants can regenerate from a variety of tissues on culturing in appropriate media. However, the metabolic shifts involved in callus formation and shoot regeneration are largely unknown. The metabolic profiles of callus generated from tomato (Solanum lycopersicum) cotyledons and that of shoot regenerated from callus were compared with the pct1-2 mutant that exhibits enhanced polar auxin transpor...

We report the isolation, sequence, and pattern of gene expression of members of the KNOTTED1 (KN1)-type class 1 homeobox gene family from rice. Phylogenetic analysis and mapping of the rice genome revealed that all of the rice homeobox genes that we have isolated have one or two direct homologs in maize. Of the homeobox genes that we tested, all exhibited expression in a restricted region of th...

1. In Bryophyllum calycinum two apical leaves suppress the shoot formation in all the dormant buds situated basally from the leaf; one apical leaf suppresses the shoot formation in the basal buds situated in the same half of the stem where the leaf is, and, if one-half of the petiole of such a leaf is removed, the growth of basal buds in one quadrant of the stem is suppressed. 2. This inhibitor...