Inflorescence architecture, floral part movements and pollinator attraction by androecia – contrivance for successful mating in Eremurus himalaicus Baker

Present study has been carried out to understand the mating strategies of Eremurus himalaicus Baker., important medicinal endemic plant, for its sustainable utilization. The inflorescence architecture, large numbers of attractive flowers, presence of sterile flowers which give specific arrangement to inflorescence, the coloured, attractive androecia and nectaries attract the pollinators. Protoandry, moderate to high pollen ovule ratio, unique movement of stigma away from dehiscing anthers, movement of pedicels and breeding experiment revealed that the species is primarily geitonogamous but xanogamy though rare is also operative. The exine sculpture and pollen size depicts that both anemophily and entomophily is operative in the species. Present study may provide important information for the conservation of this endemic medicinal plant species which has been categorized as threatened by various authors.

Interaction between Floral Merism and Symmetry: Evidence from Fasciated Mutant of Lupinus angustifolius L. (Leguminosae)

A significant diversity of flower structure in angiosperms is defined by few parameters, among which one may list floral merism and symmetry as the most important. However, observation of normal variation in different taxa indicates that high floral merism (more than six organs) is very rarely associated with a monosymmetry. Precise mechanisms underlying this tendency, as well as the mode of interaction between regulatory pathways of floral symmetry and merism, remain unidentified. In this work, we observed the floral ontogeny in normal plants of Lupinus angustifolius L. (Leguminosae), described the floral structure and its variations in fasciated mutant. Our results suggest that monosymmetry is regulated independently from the floral merism, so three types of petals differentiate properly even in flowers with an anomalously high number of organs. However, the adaxial floral domain is the most stable floral part, which is the least susceptible to the fluctuations of merism. This means that some genes responsible for the development of the adaxial flower domain may additionally stabilize it and hence prevent fluctuations of merism in the adaxial domain. The monosymmetry in Leguminosae is a character connected with pollination by insects and requires a precise interaction between all floral parts. That is why fluctuations, which impair this interaction and symmetry, may decrease the pollination efficiency.

High Frequency Regeneration of Plantlets from Immature Male Floral Explants of Musa paradisica cv. Puttabale - AB Genome

High frequency in vitro regeneration for mass multiplication from immature male floral explants of Musa paradisica cv. Puttabale on MS supplemented with adenine sulfate (160 mg/l), tyrosine (100 mg/l), sucrose (40 g/l) and gelled with 0.8 g/l agar was attempted. For callus induction the combinations of 2, 4-D and BAP were tested at 1.0 - 10.0 mg/l and 0.5 - 5.0 mg/l, respectively. For shoot bud formation combinations of BAP and TDZ were also tested at 1.0 - 5.0 mg/l and 0.1 - 0.5 mg/l, respectively. Luxuriant proliferation and high frequency induction (97.0%) of callus was noticed from the accessory floral part of the explant at 7.0 mg/l 2, 4-D and 1.0 mg/l BAP, later it preceded towards the gynoecium. Interaction of BAP (2.0 – 5.0 mg/l) and TDZ (0.2 - 0.5 mg/l) would provoke high frequency shoot bud differentiation from the floral calli and a mean of 29.40 ± 6.10 shootlets per callus was obtained at 4 mg/l BAP and 0.4 mg/l TDZ. Rooting of the microshoots was achieved on MS containing 0.6 mg/l NAA and 0.2% activated charcoal. Key words: Musa pardisica, Puttabale, Regeneration, Male floral explants. D. O. I. 10.3329/ptcb.v21i2.10243 Plant Tissue Cult. & Biotech. 21(2): 199-205, 2011 (December)

Growth relationships of individual flowers during late stages of floral development of Rhododendron L. 'Prize' and 'Gloria'

Single terminal inflorescences from two-stemmed plants of Rhododendron L. cv. 'Prize' and 'Gloria' were recurrently sampled during a 9°C cold treatment and subsequent forcing period in an 18°C growth chamber until plants reached anthesis. At each sample period, bud length and width were measured on each inflorescence, while subtending bud scale, petal, stamen ('Gloria' only), style, peduncle and ovary length, ovary width, and flower weight were determined on the two most basally attached flowers within an inflorescence for each cultivar. Polynomial regression models were calculated for each floral growth measurement over time, except for bud length and width, for each of the four flowers within a cultivar. Comparison of regression models revealed differences in floral part growth patterns among the various flowers within each cultivar. During the first week of placement in 18°C forcing temperatures after the cold treatment, bud length was the only floral part to grow on 'Prize' plants, while only female flower parts grew on 'Gloria' plants. These results indicate differences in growth resumption patterns between cultivars after cold storage. However, petal and style length were strongly correlated to flower weight for both cultivars indicating that these measurements could be used in laboratory or field situations to determine the floral stage of growth. The growth equations described would be useful for controlling the variability among shoots and flowers for analytical determinations, such as hormonal content analysis, and for studying relationships of floral growth patterns to environmental stimuli that could be used to control flowering. The statistical techniques used in this research make it possible to reduce the number of plants for such studies, as measurements taken on different flowers on the same plant can be used for floral part growth comparisons despite the inherent correlation present between such measurements.Key words: morphology, dormancy, growth modeling, multivariate multiple regression, controlled environment.

Effect of ABA and Paclobutrazol on Cold Hardiness of Blueberries

Growth regulators ABA and paclobutrazol were used at different concentrations to induce hardiness in blueberry flower buds and floral parts. Critical freezing temperatures and the effectiveness of the treatments were determined by differential thermal analysis (DTA), electrolyte leakage, visual browning, and tetrazolium staining. Treatment effects of growth regulators were nonsignificant on whole flower buds, but treatments induced hardiness in floral parts on the second flush of flowers at stage six produced in April. Induction of cold hardiness by ABA and paclobutrazol was concentration dependent. The higher the concentration, the greater the response. Viability test results on each floral part showed a close relationship with the critical freezing temperatures recorded by DTA. Control treatments showed that floral parts at stage six developed in April were more prone to freezing injury compared to floral parts at stage six developed in early March.

Carotenoids in floral parts of a narcissus, a daffodil and a tulip

1. The qualitative and quantitative distribution of carotenoids of the floral parts of three monocotyledons, the narcissus Scarlet Elegance, the daffodil King Alfred and the tulip Golden Harvest, were studied. β-Carotene, lutein or epoxy-β-carotenes were usually the main pigments, depending on the floral part and on the flower. When β-carotene was the major pigment there were only small amounts of, or sometimes no, epoxycarotenes. 2. Anthers, stigmas and styles of the three flowers did not possess any specific carotenoids but in some cases contained appreciable amounts of epoxycarotenoids. The possibility that these take part in reproduction is discussed. 3. The generalization that yellow flowers contained large amounts of xanthophylls and only traces of carotenes, whereas deep-orange flowers seemed to be characterized by the presence of large amounts of one carotene, was not always the correct one. It is suggested that the floral parts are yellow or orange depending on what carotenoids are present, which is the major one and the amount of total carotenoids, and also on the presence of other non-carotenoid pigments. 4. Two new probable isomers of 5,6:5′,6′-diepoxy-β-carotene were isolated and found together in various floral parts of the tulip Golden Harvest.