Physiological Responses of Chrysanthemum Petals during Senescence

Flower senescence was studied in three cultivars of Chrysanthemum coronarium L.: Snowball White, Yellow Chandrama (standard type flowers) and Spray Button (spray type flowers). Spray button flowers exhibited least respiration rate, less efflux of ions, minimum protease activity and less decline in fresh mass, relative water content and total soluble protein content with the progression of senescence. The Snowball White flowers showed highest respiration rate, great efflux of ions, maximum protease activity, high activity of hydrolytic as well as proteolytic enzymes, and high decline in fresh mass, relative water content, and total soluble protein content. Yellow Chandrama flowers showed responses similar to Snowball White flowers.     

Factors affecting floral herbivory in a limestone grassland

The amount of herbivore damage to the petals of 41 species of herbaceous plant was surveyed from April to September in a limestone grassland in central England. Damage was recorded as the percentage of the petal area removed. Most damage was caused by invertebrates, particularly slugs. The amount of invertebrate damage differed significantly between plant species and with time of year. The mean damage across all species was only 2 %, ranging from an average of 0 % in Galium sterneri to 8 % in Primula vulgaris. In most species, less than a quarter of flowers received any damage, so those that were damaged were often severely affected. Species flowering early or late in the season received more damage, possibly because of greater slug activity. Hypotheses to explain the inter-specific variation in the amount of herbivory were examined by testing for correlations with a range of plant variables. No correlations with flower-stem length, flower-stem thickness or the longevity of flowers were apparent. The amount of petal damage correlated strongly with flower size and petal thickness. This appeared to result from the prevalence of large-flowered species early and late in the season rather than from a preference for flower size and petal thickness per se. The evolutionary significance of floral herbivory is discussed.     

Continuous petal variation in Epimedium tianmenshanense (Berberidaceae), a taxon endemic to western Hunan,China

In the protologue, Epimedium tianmenshanense (Berberidaceae), a species endemic to western Hunan, China, was described as ‘flower small, 0.2–0.4 cm diam., inner sepals white, petals as long as inner sepals or a little shorter than the latter, spur very short, ca 5.0 mm’. However, both morphological characteristics and molecular evidence suggest that E. tianmenshanense is closely related to E. baojingense, a taxon with a long spur, thus suggesting that the size of the floral parts is not as reliable as previously believed. When investigating the variability of E. tianmenshanense in more detail, in the field as well as in cultivation, we found that the petals were are highly variable in morphology (both shape and size), being cucullate, subulate, short to long spurred, and with various transitions. The flowers size varied from small to large accordingly. The flowers with cucullate and subulate petals, which were a little shorter than the inner sepals or almost as long as the latter, were small (about 0.8 cm in diameter). The flowers with long spurs, which were much longer than the inner sepals, were also large (about 2.5–3.5 cm in diameter). Finally, the flowers with short spurs, which were a little longer than the inner sepals, were medium-sized (about 1.0–1.2 cm in diameter). In addition, the color of inner sepals was revised from ‘white, occasionally light mulberry-purple’ to yellowish green or yellowish white. Epimedium tianmenshanense is a perfect example of natural petal evolution, which could be used for further taxonomic and evolutionary studies. The reason for the variation and the taxonomic treatment of the species still need further study.     

Cell distribution and surface morphology in petals, androecia and styles of Commelinaceae

Cell distribution and surface morphology in petals, androecia and styles of Commelinaceae. Epidermal cell shape, distribution, surface topography and cuticular morphology in petals, androecia and styles of 10 species in the Commelinaceae are described. Petals of all species possess a basal area of elongated, straight-sided cells and an area of cells with sinuous, anticlinal walls. The degree of convolution of anticlinal wall and the length of cells varies between genera. The surface of cells in Aneilema, Commelina and Cyanotis are micropapillate. In all other genera they are low-domed. Cuticular surfaces of the three genera are smooth, while in the remainder heavily striated. The cells of stamens, staminodes, staminal hairs, and styles are variably elongated and straight-sided, their surfaces convex and cuticle striated. The degree of striation is less pronounced at the base of each organ but becomes more densely arrayed towards the apex. Petal pigments are located in upper epidermal cells in Tradescantia and Thyrsanthemum , in upper and lower epidermises in Dichorisandra and Commelina , and in both epidermises, and mesophyll of Aneilema. In most species pigmentation of androecium and style is similar to petals though often fainter at base and apex. Flavonols in the pigments give rise to spectral polmorphisms visible in longwave UV light. Epidermal adaptations for light capture in petals is compared to that in leaf structure.     

金花茶花瓣转录组分析及花瓣发育调控基因挖掘

花瓣大小是影响金花茶(Camellia nitidissima)观赏价值的主要因素之一,但金花茶花瓣发育形成机制尚不清楚。将金花茶花瓣发育过程划分为幼蕾期(S1)、初蕾期(S2)、显色期(S3)、半开期(S4)、盛开期(S5)五个阶段,利用RNA-seq技术分析花发育过程中转录组的动态变化,以期对金花茶花瓣发育形成的转录机理进行初步探究。通过对金花茶花瓣发育过程中的差异表达基因进行富集分析和趋势分析,发现生长素转导途径所含差异表达基因数量最多,部分AUX1/LAX共转运体、AUX/IAA基因、SAUR等生长素应答基因在开花过程中明显上调,表明生长素是调控花瓣生长重要的调控因子。MYB、bHLH、锌指蛋白等转录因子、木葡聚糖内糖基转移酶/水解酶(XTH)、果胶酯酶(PE)、果胶裂解酶(PL)等部分下游功能基因,其中XTH显著富集于GO分类中的水解酶活性,表明它们可能对金花茶花瓣的生长起重要调控作用。此外,对FT、SOC1、AP3、PI、SEP3等开花调控关键基因在金花茶花瓣发育过程中的表达情况进行了分析,结果表明这些基因主要以中低表达为主。高表达基因进行KEGG富集分析结果表明,次生代谢物质合成伴随着金花茶花瓣的整个发育过程。这些结果为进一步揭示金花茶花瓣发育的转录调控机制奠定了理论基础。