Biology subjects

Jiang, G.-F.

Publications and source records attributed to Jiang, G.-F..

6 recordsLinked to original sources

bioRxiv2024

Transpirational water loss from flowers is low but unregulated

Flowers play a critical role in reproduction for most of the flowering plants, and maintaining flowers throughout their lifespan can require substantial resources, such as carbon and water. Increases in temperature and aridity due to climate change are shifting the atmospheric conditions experienced by flowers, potentially altering the costs of floral maintenance. However, little is known about floral physiology and the capacity of flowers to regulate water loss. Because many flowers have few, if any, stomata, flowers may not be able to curtail water loss when the atmospheric demand for water vapor is high. Here, we tested whether the surface conductance of of flower petals, tepals, and showy bracts responds dynamically to changes in the vapor pressure gradient driving water loss. We measure the responses of flower surface conductance (gs) to step changes in the vapor pressure gradient on nine species. Across species, gs was low among all species, and there was little, if any, response in gs to step changes in humidity. The lack of response in gs resulted in linear responses of transpirational water loss to variation in vapor pressure deficit. These results suggest that unusually hot, dry conditions could elevate water loss from flowers, leading to premature wilting and senescence, thereby shortening floral longevity.

plant biology↗

bioRxiv2023

The effects of genome size on cell size and the functional composition and morphology of leaves: a case study in Rhododendron (Ericaceae)

Background and AimsDespite the predominance of scaling photosynthetic metabolism by two-dimensional leaf surface area, leaves are three-dimensional structures composed of multiple tissues that directly and indirectly influence photosynthetic metabolism. The structure of leaf surfaces for CO2 diffusion and light transmission and the internal volume of tissues that process energy and matter work together to control rates of resource acquisition and turnover. Here we investigate the influence of cell size and packing density on resource acquisition as measured by surface conductance to CO2 and water vapor and on resource turnover as measured by leaf water turnover time. MethodsWe sampled wild and cultivated congeneric species in the genus Rhododendron (Ericaceae) and measured genome size, anatomical traits related to cell sizes and packing densities, and morphological traits related to water content and dry mass allocation. ResultsAmong Rhododendron, anatomical traits related to cell size and morphological traits related to water content and dry mass investment varied largely orthogonally to each other, allowing for many combinations of leaf traits to exist. However, there was a strong, negative relationship between the leaf water residence time ({tau}) and the maximum leaf surface conductance per leaf volume (gmax,vol), both of which are influenced by cell size and cell packing densities. ConclusionsDespite leaf function being controlled by many potential combinations of leaf cell- and tissue-level traits, cell size has a pervasive effect on leaf function. Small cells allow for higher diffusion of CO2 and water vapor per unit leaf volume (gmax,vol) even at constant leaf thickness, but small cells also result in shorter leaf water residence times ({tau}). The strong tradeoff between gmax,vol and ({tau}) illuminates how genome size-cell size allometry influences the fast-slow continuum of plant carbon and water economy.

plant biology↗

bioRxiv2022

Mangroves deviate from other angiosperms in their genome size, leaf cell size, and cell packing density relationships

Background and AimsWhile genome size limits the minimum sizes and maximum numbers of cells that can be packed into a given leaf volume, mature cell sizes can be substantially larger than their meristematic precursors and vary in response to abiotic conditions. Mangroves are iconic examples of how abiotic conditions can influence the evolution of plant phenotypes. MethodsHere, we examined the coordination between genome size, leaf cell sizes, and cell packing densities, and leaf size in 13 mangrove species across four sites. Four of these species occurred at more than one site, allowing us to test the effect of climate on leaf anatomy. ResultsWe found that genome sizes of mangroves were very small compared to other angiosperms, and, like other angiosperms, mangrove cells were always larger than the minimum size defined by genome size. Increasing mean annual temperature of a growth site led to higher packing densities of veins (Dv) and stomata (Ds) and smaller epidermal cells but had no effect on stomatal size. Contrary to other angiosperms, mangroves exhibited (1) a negative relationship between guard cell size and genome size; (2) epidermal cells that were smaller than stomata, and (3) coordination between Dv and Ds that was not mediated by epidermal cell size. Furthermore, mangrove epidermal cell sizes and packing densities covaried with leaf size. ConclusionsWhile mangroves exhibited coordination between veins and stomata and attained a maximum theoretical stomatal conductance similar to other angiosperms, the tissue-level tradeoffs underlying these similar relationships across species and environments was markedly different, perhaps indicative of the unique structural and physiological adaptations of mangroves to their stressful environments.

ecology↗

bioRxiv2019

The scaling of genome size and cell size limits maximum rates of photosynthesis with implications for ecological strategies

A central challenge in plant ecology is to define the major axes of plant functional variation with direct consequences for fitness. Central to the three main components of plant fitness (growth, survival, and reproduction) is the rate of metabolic conversion of CO2 into carbon that can be allocated to various structures and functions. Here we (1) argue that a primary constraint on the maximum rate of photosynthesis per unit leaf area is the size and packing density of cells and (2) show that variation in genome size is a strong predictor of cell sizes, packing densities, and the maximum rate of photosynthesis across terrestrial vascular plants. Regardless of the genic content associated with variation in genome size, the simple biophysical constraints of encapsulating the genome define the lower limit of cell size and the upper limit of cell packing densities, as well as the range of possible cell sizes and densities. Genome size, therefore, acts as a first-order constraint on carbon gain and is predicted to define the upper limits of allocation to growth, reproduction, and defense. The strong effects of genome size on metabolism, therefore, have broad implications for plant biogeography and for other theories of plant ecology, and suggest that selection on metabolism may have a role in genome size evolution.

ecology↗

bioRxiv2019

The complete mitochondrial genome of the Golden Birdwing butterfly Troides aeacus: insights into phylogeny and divergence times of the superfamily Papilionoidea

BackgroundThe Lepidoptera is one of the largest insect orders. Previous studies on the evolution of Lepidoptera did not confidently place butterflies, and many relationships among superfamilies in the megadiverse clade Ditrysia remain largely uncertain. Here, we generated a molecular dataset with 78 species of lepidopterian insects, including a new complete mitochondrial genome (mitogenome) sequences of the Golden Birdwing Butterfly, Troides aeacus, which was listed in appendix II of CITES. MethodsBased on the concatenated nucleotide sequences of 13 protein-coding genes, we constructed phylogenetic trees with Bayesian Inference (BI) and Maximum Likelihood (ML) methods, and calculated the divergence times of Lepidoptera. ResultsMonophyly of the Papilionoidea including skippers (Hesperiidae) is strongly supported by a high bootstrap value. Butterflies were placed sister to the remaining obtectomeran Lepidoptera, and the latter was grouped with high bootstrap supports. Additionally, Papilionidae probably diverged from the group (Hesperiidae + (Nymphalidae + Pieridae)) at 102.65 Mya, the Early Cretaceous. T. aeacus and the Golden kaiserihind Teinopalpus aureus diverged in the Cretaceous of 85.32 Mya. The age of Papilionoidea indicates that the primary break up of Gondwana may have an effect on the current distributions of butterflies.

evolutionary biology↗

bioRxiv2018

Hydraulic traits are more diverse in flowers than in leaves

Introduction Introduction Methods Results Discussion References The appearance of modern flowers was a turning point in the evolution of flowering plants, enhancing the intimacy and extent of interactions with their animal pollinators and increasing the likelihood of successful outcrossing (Crane et al., 1995; Fenster et al., 2004). Flowers evolved new morphological traits and rapidly diversified, effectively increasing the number of axes along which species could differentiate (Stebbins, 1951; Crepet & Niklas, 2009). Flowers are often noted for their incredible diversity of form, with high amounts of variation existing across phylogenetic scales, from within species to among major clades (Chartier et al., 2014, ...

evolutionary biology↗