Showing papers on "Plant morphology published in 2021"

Overexpression of PIF4 affects plant morphology and accelerates reproductive phase transitions in soybean

Abstract: Phytochrome-interacting factor 4 acts as a signalling hub for integrating multiple environmental cues like light and temperature. While the function of PIF4 in the model plant Arabidopsis has been studied, there is limited knowledge regarding the role of PIF4 in agronomically important legume crop soybean. Here, we employed a constitutive overexpression approach to functionally characterise a soybean PIF4 homolog, GmPIF4b in a determinate short-day cultivar, Bragg. Multiple sequence alignment of seven soybean PIF4 homologs (GmPIF4a-g) with Arabidopsis PIF4 revealed the presence of an active phytochrome-binding (APB) domain in the N-terminal region of six soybean PIF4 homologs. Cis-elements related to plant hormone biosynthesis, stress response, meristem and endosperm gene expression were located in the promoter region of soybean PIF4s. Interestingly, transgenic soybean plants carrying 35s::GmPIF4b::polyA construct showed reduced plant height, reduced leaf surface area, decreased branching, early flowering and faster transition from full-bloom flowering stage to full maturity stage without any decline in yield. Further, pod colour of transgenic soybean plants changed to dark brown, whereas wild-type plants showed tan or light brown pod colour. Clear hilum was observed in seeds obtained from transgenic plants as opposed to the dark or black hilum of wild-type seeds. Transcripts of soybean florigens GmFT2a and GmFT5a were also elevated in transgenic plants. Collectively, our results suggest that GmPIF4b overexpression could affect phenotypes related to plant morphology and reproductive stages in soybean, and can be used as a gene target for soybean improvement programmes to ensure future food security.

Effects of Light Intensity, Spectral Composition, and Paclobutrazol on the Morphology, Physiology, and Growth of Petunia, Geranium, Pansy, and Dianthus Ornamental Transplants

Abstract: Under light-limiting conditions, many ornamental greenhouse-grown plants show undesired morphological characteristics, such as plant elongation (hypocotyl and epicotyl length) and low dry mass, which reduce plant quality. Research has shown that use of plant growth regulators (PGRs) and changes in both light intensity and spectral composition can reduce these undesired characteristics. However, little is known about the role of the combined effects of supplemental lighting and PGRs on the production of ornamental seedlings. The objective of this study was to characterize the combined and independent effects of light intensity, spectral composition, and PGR applications on the greenhouse production of ornamental transplants. Petunia (Petunia × hybrida), geranium (Pelargonium × hortorum), pansy (Viola × wittrockiana) and dianthus (Dianthus chinensis) were grown for 32–42 days under three supplemental light (SL) treatments: 1) high-pressure sodium (HPS), 2) light-emitting diodes (LEDs) with a 6 blue (B):5 green (G):89 red (R) (percent photon flux ratio), and 3) LEDs with 19B:81R (100 μmol m−2 s−1, 18 h photoperiod for all treatments). A control (No SL) was also included. In addition, a portion of plants were also sprayed with the paclobutrazol PGR (PBZ and No PBZ). The synergistic effects of the combination of PBZ and supplemental lighting resulted in the most compact plants, caused by a reduction in plant height by PBZ and an increase in dry mass by SL. However, PBZ reduced shoot dry mass of most plant species and light combinations. Plant compactness was greater under the 6B:5G:89R LED composition for petunia and when combined with PBZ for geranium than for plants under HPS lighting. Root dry mass of petunia, geranium, and pansy plants increased in response to SL compared with no SL by 2.4–5.7-fold. Results from the two LED spectra were unexpected; plants under 6B:5G:89R were more compact (petunia, geranium), had higher anthocyanin concentrations (petunia), were shorter (petunia, pansy, dianthus) and had less leaf area (petunia, pansy, dianthus) than plants in the SL treatment with a higher B and lower G PF (19B:81R). Supplemental lighting and PBZ can be used in conjunction or independently to improve plant morphology. The increased light from SL provided the most benefits by improving dry mass, compactness, and leaf number for most plant species. However, when PBZ was used in combination with SL, plant compactness increased for some species. The spectral composition of SL had an impact on plant growth and morphology, warranting additional research on plant responses to small changes in the spectral composition of SL.

Intraspecific morphological variation of Bellidiastrum michelii (Asteraceae) along a 1,155 m elevation gradient in the Tatra Mountains

Abstract: Plant species that inhabit large elevation gradients in mountain regions are exposed to different environmental conditions. These different conditions may influence plant morphology via plastic responses and/or via genetic adaptation to the local environment. In this study, morphological variation was examined for Bellidiastrum michelii Cass. (Asteraceae) plants growing along a 1,155 m elevation gradient in the Tatra Mountains in Central Europe. The aim was to contribute to gaining a better understanding of within-species morphological variation in a mountain species across elevation gradients. Twelve morphological traits, which were measured for 340 plants collected from 34 sites, were plotted against elevation using Generalised Additive Models. Significant variation in B. michelii morphology was found across the elevation gradient. Plant size, in the form of plant height, total aboveground mass and total leaf mass, decreased significantly with increasing elevation. Similarly, floral traits, such as flower head mass, total flower mass, individual flower mass, flower head diameter and ligulate and tubular flower length, also decreased significantly with increasing elevation. However, the changes in these floral traits were not as large as those observed for plant size traits. Interestingly, the number of flowers produced by the plant, both ligulate and tubular, did not change across the studied elevation gradient. In this study, elevation was found to be an important gradient across which significant intraspecific morphological variation occurred in a mountain plant. These morphological changes may have occurred in response to various abiotic and biotic factors that change along elevation gradients.

The aquatic species Pontederia azurea and P. crassipes (Pontederiaceae) in the Pantanal, Brazil: evidence of how plant structure can simultaneously reflect phylogeny and ecology

Abstract: Hydric fluctuations in the Pantanal comprise annual dry and wet seasons that modify local diversity and plant morphology and anatomy. Widespread in this wetland are the sympatric Pontederia azurea and P. crassipes, which, although primarily aquatic, can also develop in non-flooded environments. This study undertook a comparative investigation of the qualitative and quantitative phenotypic responses and strategies of these two species (regarding life-form and leaf morpho-anatomy) in moderately dry and aquatic environments in the Pantanal. Field observations, conventional methods in plant anatomy, and leaf biometry were performed, followed by statistical analyses. Phenotypic responses, such as the decreased size of lacunae, increased lignification of vessel elements, and storage of starch granules, are the most prominent responses associated with moderately dry environments. The ability of petioles to elongate and inflate seems to be closely related to specific morphological patterns of each species. In contrast, petiole length, leaf blade dimensions, size of lacunae, and lignification rates seem to be somewhat associated with water level fluctuations. Our results provide evidence of how plant structure can simultaneously reflect phylogeny and ecology, thus supporting further investigations into phenotypic plasticity.

Роды Tchihatchewia и Horwoodia (Сruciferae): Критические заметки

Abstract: The genus Tchihatchewia Boiss and genus Horwoodia Turill have a number of common morphological characters (winged, 1‑2 seeded silicles, lilac flowers with appressed sepals, plant pubescence with bristly hairs, and erect highly branching plants) and geographic‑ecological characters (Southwest Asian arid, subarid and aridized habitats) that allow their combining into one genus Tchihatchewia Boiss, consisting of two species: T isatidea Boiss and T dicksoniae (Turrill) VI Dorof comb nov

Leaf age is important for assessment of resistance in chrysanthemum against Frankliniella occidentalis

Abstract: Feeding behaviour of pest insects on host plants depends on the plant morphology and chemical composition. So far, leaf position was demonstrated important for estimation of thrips resistance in Capsicum, where resistant associations showed a higher resistance in the youngest leaves compared to old leaves. In the current study, the feeding behaviour of female Frankliniella occidentalis, a major pest of chrysanthemum, and the egg-laying activity was assessed in a non-choice experiment in the climate chamber. We hypothesize that the physiological status, i.e. the age of chrysanthemum leaves, is an important resistance factor influencing thrips silver damage and the number of offspring. In general, the results show significantly higher feeding damage on old (basal) leaves of susceptible cultivars compared to resistant cultivars on the abaxial side of the leaf. In contrast, we detected no significant differences on the adaxial side of the leaves neither for old nor for young leaves. However, feeding damage on different leaf positions is an important factor for resistance level determination. Additionally, we detected significant differences in reproductive activity, i.e. number of hatched larvae on old leaves compared to young leaves for all cultivars. Overall, on old leaves we detected more larvae. The comparison between the old leaves of all cultivars exhibited a significant difference between one resistant and one susceptible cultivar. Contrary to that, the comparison between the young leaves of all cultivars exhibited no significant differences. All findings are important for advancing future resistance screenings in chrysanthemum.

Impact of Three Different Light Spectra on the Yield, Morphology and Growth Trajectory of Three Different Cannabis sativa L. Strains.

Abstract: Cannabis is one of the oldest cultivated plants, but plant breeding and cultivation are restricted by country specific regulations. Plant growth, morphology and metabolism can be manipulated by changing light quality and intensity. Three morphologically different strains were grown under three different light spectra with three real light repetitions. Light dispersion was included into the statistical evaluation. The light spectra considered had an influence on the morphology of the plant, especially the height. Here, the shade avoidance induced by the lower R:FR ratio under the ceramic metal halide lamp (CHD) was of particular interest. The sugar leaves seemed to be of elementary importance in the last growth phase for yield composition. Furthermore, the last four weeks of flowering were crucial to influence the yield composition of Cannabis sativa L. through light spectra. The dry flower yield was significantly higher under both LED treatments compared to the conventional CHD light source. Our results indicate that the plant morphology can be artificially manipulated by the choice of light treatment to create shorter plants with more lateral branches which seem to be beneficial for yield development. Furthermore, the choice of cultivar has to be taken into account when interpreting results of light studies, as Cannabis sativa L. subspecies and thus bred strains highly differ in their phenotypic characteristics.