Genome Size and Labellum Epidermal Cell Size Are Evolutionarily Correlated With Floral Longevity in Paphiopedilum Species

Genome size is known to influence phenotypic traits in leaves and seeds. Although genome size is closely related to cellular and developmental traits across biological kingdoms, floral longevity is a floral trait with important fitness consequence, but less is known about the link between floral longevity and sizes of genomes and cells. In this study, we examined evolutionary coordination between genome size, floral longevity, and epidermal cell size in flowers and leaves in 13 Paphiopedilum species. We found that, across all the study species, the genome size was positively correlated with floral longevity but negatively associated with labellum epidermal cell size, and a negative relationship was found between floral longevity and labellum epidermal cell size. This suggested that genome size is potentially correlated with floral longevity, and genome size has an important impact on life-history trait. In addition, genome size was positively correlated with leaf epidermal cell size, which was different from the relationship in flower due to different selective pressures they experienced or different functions they performed. Therefore, genome size constraints floral longevity, and it is a strong predictor of cell size. The impact of genome size on reproduction might have more implications for the evolution of flowering plants and pollination ecology.

KAJIAN STRUKTUR ANATOMI DAN MORFOLOGI DAUN PLANLET PISANG KEPOK KUNING HASIL PEMBERIAN EKSTRAK UMBI KEMBANG SUNGSANG SECARA IN VITRO

Plantain is a fruit commodity that has a high level of market demand, but the yield is low. To overcome this problem, tissue culture techniques are used to increase plantlet production in a short time. Plantain have parthenocarpy character, high sterility, and different levels of ploidy. Tissue culture with the addition of flame lily tuber biomutagen containing colchicine was used as a strategy to overcome the above constraints because it was thought to increase the production of polyploid banana plantlets. Changes in the anatomical and morphological structures are indicators of polyploidy. The purpose of this study was to obtain information on changes in the anatomical and morphological structures of plantain leaves as a result of giving in vitro plantlet propagation media as an indicator of the formation of polyploidy. Plantlets were grown on tissue culture media supplemented with three treatments: 10% flame lily tuber extract, 0.1% pure colchicine, and without addition (control). The parameters observed were epidermal cell size, stomata size, stomata index, number and leaf area. Epidermal cell size, stomata size and stomatal index were analyzed using range values ​​and mean values. The number of leaves, and the average wide of leaf, is then shown in the form of a bar chart. The results showed that administration of flame lily tuber extract was able to increase epidermal cell size, stomata size, wide of a leaf, and able to reduce the stomata index and number of leaves.

Micro-morphological studies in some species of Dichanthium Willemet (Poaceae) from Maharashtra, India

The present study was carried out to determine the micro-morphology of some species of Dichanthium Willemet (Poaceae) from Maharashtra. Species of Dichanthium were collected from the different localities of Maharashtra for detailed micro-morphological study. Epidermal studies pertains to epidermal cell size, presence and absence of micro-hairs, papillae, its types of silica bodies of species of Dichanthium. All the 7 studied members show the variation in the types and arrangement of the epidermal cells of leaf.

Vein density is independent of epidermal cell size in Arabidopsis mutants

Densities of leaf minor veins and stomata are co-ordinated within and across vascular plants. This maximises the benefit-to-cost ratio of leaf construction by ensuring stomata receive the minimum amount of water required to maintain optimal aperture. A ‘passive dilution’ mechanism in which densities of veins and stomata are co-regulated by epidermal cell size is thought to facilitate this co-ordination. However, unlike stomata, veins are spatially isolated from the epidermis and thus may not be directly regulated by epidermal cell expansion. Here, we use mutant genotypes of Arabidopsis thaliana (L.) Heynh. with altered stomatal and epidermal cell development to test this mechanism. To do this we compared observed relationships between vein density and epidermal cell size with modelled relationships that assume veins and stomata are passively diluted by epidermal cell expansion. Data from wild-type plants were consistent with the ‘passive dilution’ mechanism, but in mutant genotypes vein density was independent of epidermal cell size. Hence, vein density is not causally linked to epidermal cell expansion. This suggests that adaptation favours synchronised changes to the cell size of different leaf tissues to coordinate veins and stomata, and thus balance water supply with transpirational demand.