Barley Genotypes Vary in Stomatal Responsiveness to Light and CO2 Conditions

Abstract

Changes in stomatal conductance and density allow plants to acclimate to changing environmental conditions. In the present paper, the influence of atmospheric CO2 concentration and light intensity on stomata were investigated for two barley genotypes—Barke and Bojos, differing in their sensitivity to oxidative stress and phenolic acid profiles. A novel approach for stomatal density analysis was used—a pair of convolution neural networks were developed to automatically identify and count stomata on epidermal micrographs. Stomatal density in barley was influenced by genotype, as well as by light and CO2 conditions. Low CO2 conditions resulted in increased stomatal density, although differences between ambient and elevated CO2 were not significant. High light intensity increased stomatal density compared to low light intensity in both barley varieties and all CO2 treatments. Changes in stomatal conductance were also measured alongside the accumulation of pentoses, hexoses, disaccharides, and abscisic acid detected by liquid chromatography coupled with mass spectrometry. High light increased the accumulation of all sugars and reduced abscisic acid levels. Abscisic acid was influenced by all factors—light, CO2, and genotype—in combination. Differences were discovered between the two barley varieties: oxidative stress sensitive Barke demonstrated higher stomatal density, but lower conductance and better water use efficiency (WUE) than oxidative stress resistant Bojos at saturating light intensity. Barke also showed greater variability between treatments in measurements of stomatal density, sugar accumulation, and abscisic levels, implying that it may be more responsive to environmental drivers influencing water relations in the plant.

Performance of the growth and yields of some local varieties of garlic (Allium sativum l.) in medium lands

“…The results of research by [27] show that stomata characters are species-specific. And can be influenced by genetic and environmental changes such as light and CO2 concentration in the atmosphere [28] or land type [30]. Stomata function for the process of transpiration in plants, while the main function of leaf stomata is the exchange of gases needed by plants for the process of photosynthesis.…”

Agronomic responses of four garlic genotypes in two different locations

“…Higher air humidity with considerable dry soil can trigger stomata opening (Driesen et al, 2020). Previous studies also revealed that stomatal characters were species-specific (Zhang et al, 2012) and affected by both genetic and environmental changes such as light and CO2 concentration in the atmosphere (Hunt et al, 2021) or land type (Sun et al, 2021). Analysis of variance showed that the number of leaves was significantly affected by independent G×L interaction , while chlorophyll content (SPAD value) was significantly affected only by genotypic factors regardless of location (Table 4).…”

Regulation of Phenolic Compound Production by Light Varying in Spectral Quality and Total Irradiance

“…Nevertheless, the possible presence of other LMWA with strong antioxidant activity in extracts cannot be excluded. Interestingly, in plant organs most exposed to UV-B radiation, the synthesis of HCA derivatives declines in favor of flavonoids [ 80 , 81 ], even though HCAs absorb UV-B more efficiently than flavonoids [ 82 ] and accumulation of HCAs is associated with higher tolerance of oxidative stress among barley genotypes [ 83 ]. As shown in Arabidopsis, acylation of some PheCs (such as saiginols) may enhance their UV-B absorption properties, which confers a fitness advantage to plants that produce them following exposure to prolonged UV-B [ 84 , 85 ].…”