A Draft Genome of the Ginger Species Alpinia nigra and New Insights into the Genetic Basis of Flexistyly.

Angiosperms possess various strategies to ensure reproductive success, such as stylar polymorphisms that encourage outcrossing. Here, we investigate the genetic basis of one such dimorphism that combines both temporal and spatial separation of sexual function, termed flexistyly. It is a floral strategy characterised by the presence of two morphs that differ in the timing of stylar movement. We performed a de novo assembly of the genome of Alpinia nigra using high-depth genomic sequencing. We then used Pool-seq to identify candidate regions for flexistyly based on allele frequency or coverage differences between pools of anaflexistylous and cataflexistylous morphs. The final genome assembly size was 2 Gb, and showed no evidence of recent polyploidy. The Pool-seq did not reveal large regions with high FST values, suggesting large structural chromosomal polymorphisms are unlikely to underlie differences between morphs. Similarly, no region had a 1:2 mapping depth ratio which would be indicative of hemizygosity. We propose that flexistyly is governed by a small genomic region that might be difficult to detect with Pool-seq, or a complex genomic region that proved difficult to assemble. Our genome will be a valuable resource for future studies of gingers, and provides the first steps towards characterising this complex floral phenotype.

5,6-dehydrokawain from the rhizome of Alpinia mutica Roxb. induced proangiogenic tumour-derived VEGF of HT-29 colorectal cancer.

Vascular endothelial growth factor (VEGF) is a glycoprotein vital to the regulation of vascular endothelial cells proliferation, migration and angiogenesis. The expression of VEGF is required for the formation of new blood vessels critical in supplying oxygen and nutrition in the course of tumorigenesis. The present study investigated the effect of 5,6-dehydrokawain isolated from the rhizomes of Alpinia mutica on VEGF expression in vitro using HT-29 cell line. The results revealed that 5,6-dehydrokawain induced the expression of proangiogenic tumour-derived VEGF of HT-29 cells, which may explain the inability of 5,6-dehydrokawain in suppressing cancer cells proliferation.

[Microscopic identification of dai medicine alpiniae kwangsiensis rhizoma and its confused species].

OBJECTIVE: To observe microscopic characteristics of rhizome of Alpinia kwangsiensis, Alpinia platychilus, Alpinia blepharocalyx, and to provide basis for their identification. METHODS: Microscopic identification of root transverse section by paraffin tissue section and free-hand section and powder were carried out to distinguish them. RESULTS: The microscopic identification can be made by cell structure of epidermis and endodermis, the existence of nonglandular hair, the lignification degree of vascular bundle fiber, the number and existence style of vascular bundle fiber, the number and size of tube, and so on. The powder identification can be made mainly according to the existence of nonglandular hair and spiral vessel, the shape of starch grain, and so on. CONCLUSION: The microscopic characteristics of rhizome can provide basis for the identification of three Alpinia species.

Why do stigmas move in a flexistylous plant?

Flexistyly is a recently documented stylar polymorphism involving both spatial and temporal segregation of sex roles within hermaphroditic flowers. Using the experimental manipulation of stigma movement in self-compatible Alpinia mutica, we tested the hypothesis that selection for reducing interference between male and female function drives the evolution and/or maintenance of stigma movement. In experimental arrays, anaflexistylous (protogynous) flowers served as pollen donors competing for mating opportunities on cataflexistylous (protandrous) flowers. The pollen donors were either manipulated so their stigmas could not move or were left intact, and their success was determined using allozymes to assess the paternity of recipient seeds. We found that manipulated flowers sired a significantly smaller proportion of seeds, showing that stigma movement in unmanipulated plants increased male fitness. This result was strongest under conditions in which pollen competition was expected to be highest, specifically when pollinators visited multiple donor plants before visiting recipient flowers.

Adaptive significance of flexistyly in Alpinia blepharocalyx (Zingiberaceae): a hand-pollination experiment.

BACKGROUND AND AIMS: Flexistyly is a sexual dimorphism where there are two morphs that differ in the temporal expression of sexual function and also involve reciprocal movement of the stigmatic surface through a vertical axis during the flowering period. The adaptive significance of flexistyly has been interpreted as a floral mechanism for outcrossing, but it may also function to reduce sexual interference in which styles and stigmas impede the pollen export. Here these two explanations of flexistyly were tested in Alpinia blepharocalyx through a hand-pollination experiment. METHODS: Hand-pollinations were performed in two temporal morphs and consisted of two sequential pollination treatments, namely self-pollination in the morning and inter-morph pollination in the afternoon (treatment 1) or conversely inter-morph pollination in the morning and self-pollination in the afternoon (treatment 2), and two simultaneous self- and inter-morph cross-pollination treatments either in the morning (treatment 3) or in the afternoon (treatment 4). Seed paternity was then determined to assess relative success of self- versus cross-pollen using allozyme markers. KEY RESULTS: In the sequential pollination treatments, whether the stigmas of recipients are receptive in the morning is crucial to the success of the pollen deposited. When the cataflexistylous (protandrous) morph served as pollen recipient, early-arriving pollen in the morning can sire only a very small proportion (<15%) of seeds because the stigmas were then unreceptive. However, when the anaflexistylous (protogynous) morph served as pollen recipient, early pollen did gain a large competitive advantage over the late pollen, particularly when cross-pollen arrived first. Simultaneous self- and inter-morph cross-pollination indicated that outcross-pollen is more competitive than self-pollen on receptive stigmas. CONCLUSIONS: Differential maturing of male and female organs in Alpinia blepharocalyx is sufficient for selfing avoidance, obviating the need for style movements. Instead, the upward style curvature of the cataflexistylous morph in the morning and the anaflexistylous morph in the afternoon most likely represents a means of reducing interference with pollen export.

[Pharmacognostical studies on the rhizome and root of Alpinia nigra].

Morphological and histological characters of the rhizome and root of Alpinia nigra (Gaertn.) Burtt, used as the origin of a traditional Chinese medicine, were described and illustrated with line drawing. These studies provide referential information for the identification and quality control.

[Pharmacognostical studies on the rhizome, root and leaf of Alpinia jianganfeng T.L. Wu].

Morphological and histological characters of the rhizome, root and leaf of Alpinia jianganfeng T.L. Wu used as the origin of a traditional Chinese medicine, were described and illustrated with line drawing. These studies provide referential information for the identification and quality control.