Flower morphology of Allium(Amaryllidaceae)and its systematic significance

Allium is a complicated genus that includes approximately 1000 species.Although its morphology is well studied,the taxonomic importance of many morphological traits,including floral traits,are poorly understood.Here,we examined and measured the floral characteristics of 87 accessions of 74 Allium taxa(belonging to 30 sections and nine subgenera)from Central to Eastern Asian countries.We then examined the taxonomic relationships between select flower characteristics and a phylogenetic tree based on ITS sequences.Our results confirm that floral morphology provides key taxonomic information to assess species delimitation in Allium.We found that perianth color is an important characteristic within the subg.Melanocrommyum,Polyprason,and Reticulatobulbosa.In subg.Allium,Cepa,and Rhizirideum,significant characteristics include ovary shape,perianth shape,and inner tepal apex.For species in subg.Angunium,the key taxonomic character is ovule number(only one ovule in per locule).In the subg.Allium,Cepa,Polyprason,and Reticulatobulbosa,which belong to the third evolutionary line of Allium,hood-like appendages occur in the ovary,although these do not occur in subg.Rhizirideum.Our results also indicated that the flower morphology of several species in some sections are not clearly distinguished,e.g.,sect.Sacculiferum(subg.Cepa)and sect.Tenuissima(subg.Rhizirideum).This study provides detailed photographs and descriptions of floral characteristics and information on general distributions,habitats,and phenology of the studied taxa.

Description of Flower Biology of Under-Exploited Species, <i>Zingiber barbatum</i>(Wall.) from Myanmar

Characterization of the reproductive morphology in genus Zingiber is still relevant on classical taxonomic studies because most of the species are phenotypically similar and difficult to distinguish in the absence of the flowering stage. Reports mainly derived based on the herbarium collections are insufficient for the detailed morphological review. Zingiber barbatum (Wall.) belongs to the genus Zingiber and has been neglected for a long time. Existed intraspecific morphological and genetic variations also intricate the description of this species. The objective of this study was to characterize the reproductive morphology of under-exploited Z. barbatum species. The study was done based on the traditional description of morphology and habit of inflorescence and flowers, with a recording of minimum quantitative and qualitative parameters and phenological observation regarding inflorescence life span and duration of blossom. Assessment of reproductive morphology displayed phenotypic variations regarding inflorescences habit during the growth stage and morphological features of the flower. Perhaps, an existed variation was driven by eco-geographical factors resulting in reproductive isolation due to which genetic divergence might occur. The taxonomic affiliation of Z. barbatum based on inflorescence habit has been confirmed. This is the first comprehensive report regarding flower biology on Z. barbatum.

Pollen development and multi-nucleate microspores of Populus bolleana Lauche

Populus bolleana is a variety of P. alba, commonly used in poplar breeding programs in China. Developmental biology that involves staminate flowers, microsporogenesis and microgametogenesis ofP. bolleana is essential for Populus improvement in cross breeding for better characteristics in sexual reproduction. Flower morphology and pollen development were described and illustrated using anatomical, sectioning and stain-clearing techniques. The results show that microsporocytes undergo a regular meiotic process, but some multi-nucleate microspores occur at the microspore stage. It takes five days for microsporocytes to develop to mature pollen by forcing flower branches under greenhouse conditions. Additionally, an important relationship was found between stages of meiosis and anther colors. Microspore tetrads formed when the anther color turned yellow, whereas, when the pollen matured, the anther was red and the tapetum degenerated completely. When mature pollen grains are formed, flower buds develop into male catkins. In the end, filament elongated and pollen grains were released from dehisced anthers.

Phenotypic trait matching predicts the topology of an insular plant–bird pollination network

Conceptualizing species interactions as networks has broadened our understanding of ecological communities.However,the factors shaping interaction patterns among species and,therefore,network structure remain unclear.One potentially important factor is the matching of phenotypic traits.Here,we tested for trait matching in a bird–flower visitation network from New Zealand.We first quantified the overall network structure and tested whether flower size could account for differences in the visitation rates of flowering plants.We then explored the relationship between the flower size and bill size.The results showed that the interaction network is nested.Plant species with large flowers received more visits from birds than plant species with small flowers.Moreover,plant species with large flowers were visited more frequently by birds with large bills,while species with smaller flowers were visited more frequently by birds with small bills.Overall,the interaction patterns between birds and flowering plants could be predicted by their morphology,suggesting that phenotypic trait matching is an important predictor of network structure.