Abstract:In a controlled environment, light from light-emitting diodes (LEDs) has been associated with affecting the leaf characteristics of Eustoma. LEDs help plant growth and development, yet little is known about photosynthetic performance and related anatomical features in the early growth stage of Eustoma leaves. In this study, we examined the effects of blue (B), red (R), and white (W) LEDs on the photosynthetic performance of Eustoma leaves, as well as leaf morphology and anatomy including epidermal layer thickness, palisade cells, and stomatal characteristics. Leaves grown under B LEDs were thicker and had a higher chlorophyll content than those grown under the R and W LEDs. Leaves under B LEDs had greater net photosynthetic rates (A), stomatal conductance (g s ), and transpiration rates (E), especially at a higher photon flux density (PPFD), that resulted in a decrease in the intercellular CO 2 concentration (C i ), than leaves under the W and R LEDs. B LEDs resulted in greater abaxial epidermal layer thickness and palisade cell length and width than the R and W LED treatments. The palisade cells also developed a more cylindrical shape in response to the B LEDs. B LED leaves also showed greater guard cell length, breadth, and area, and stomatal density, than W or R LEDs, which may contribute to increased A, g s and E at higher PPFDs.

Soil microbial communities play a crucial role in soil fertility, sustainability, and plant health. However, intensive agriculture with increasing chemical inputs and changing environments have influenced native soil microbial communities. Approaches have been developed to study the structure, diversity, and activity of soil microbes to better understand the biology and plant-microbe interactions in soils. Unfortunately, a good understanding of soil microbial community remains a challenge due to the complexity of community composition, interactions of the soil environment, and limitations of technologies, especially related to the functionality of some taxa rarely detected using conventional techniques. Culture-based methods have been shown unable and sometimes are biased for assessing soil microbial communities. To gain further knowledge, culture-independent methods relying on direct analysis of nucleic acids, proteins, and lipids are worth exploring. In recent years, metagenomics, metaproteomics, metatranscriptomics, and proteogenomics have been increasingly used in studying microbial ecology. In this review, we examined the importance of microbial community to soil quality, the mystery of rhizosphere and plant-microbe interactions, and the biodiversity and multi-trophic interactions that influence the soil structure and functionality. The impact of the cropping system and climate change on the soil microbial community was also explored. Importantly, progresses in molecular biology, especially in the development of high-throughput biotechnological tools, were extensively assessed for potential uses to decipher the diversity and dynamics of soil microbial communities, with the highlighted advantages/limitations.

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Transferring in vitro-cultured Eustoma seedlings to an ex vitro condition (acclimation) 11is a big challenge that may expose the seedlings to biotic and abiotic stresses, and affect the 12 internal and external structure of the plants. In addition, in vitro-cultured seedlings of Eustoma 13 are difficult to handle and phenotype and physiological traits such as survival and rosette rate 14 may have altered in the acclimation stage. Therefore, the present study aims to examine the 15 effects of blue, red, and white LED light on the growth and development ex vitro of in vitro-16 cultured seedlings of Eustoma. The results showed that blue LEDs resulted in greater plant 17 height, internode length, and leaf number, increased upper and lower fresh biomass, and higher 18 chlorophyll content compared with treatment by the other LED lights. Higher stomatal density 19 on the abaxial leaf surface was also observed in the blue LED-treated plants, which also showed 20 a higher survival rate and lower rosette rate. In contrast, the white LED-treated plants had the 21 highest leaf width and internode diameter. Acclimation of the Eustoma plants ex vitro suggests 22 that a combination of blue and white LEDs may be advantageous for better growth and 23 development for large-scale production in a controlled environment. Stomata observation 117Mature leaf samples were collected from the 45-day-old plants grown under the blue, 118 red, and white LEDs and immediately kept in autoclaved water. Leaves were manually cut into 119 thin transverse sections using a double-edged disposable razor blade on a rubber-cutting mat 4,23 . 120Leaf of independent LEDs was fixed in Toluidin Blue (Sigma Aldrich, USA) for 30 s. To observe 121 the stomata, transparent fingernail polish was smeared on the lower epidermis of the fully 122 expanded leaves and allowed to dry for 5-10 min. The slides were made using the leaf 123 epidermal fingerprint with transparent nail polish method 24 . Clear cellophane tape was fixed 124 over the section of nail polish and carefully peeled from the leaf, and the 'leaf impression' was 125 transferred to a microscope slide. Imprints were observed under a light microscope (Olympus 126 DX-50; Olympus, Tokyo, Japan) equipped with a digital microscope camera (Olympus DP-12; 127Tokyo, Japan) at a magnification of 200×. 128 129 Statistical analysis 130 Results and Discussion 136 Effect of LEDs on seedling growth ex vitro 137The different LED light qualities influenced the growth traits in the acclimation 138 environment of Eustoma ex vitro. Plant height, leaf number, leaf length, and leaf width differed 139 significantly according to the LED light treatments ex vitro (Figure 2). The tallest plant (11.3 ± 140 0.34 cm) resulted from blue LED treatment, and the mean height of the plants differed 141 significantly among the blue, red, and white LED lights ( Figure 2A and Figure 3). The highest 142 number of leaves (15.2 ± 0.37) was found in the plants grown under the blue LEDs, and the 143 lowest number of leaves resulte...

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