Blue Light Improves Stomatal Function and Dark-Induced Closure of Rose Leaves (Rosa x hybrida) Developed at High Air Humidity

Abstract

Plants developed under constant high (>85%) relative air humidity (RH) have larger stomata that are unable to close completely in response to closing stimuli. Roses (Rosa x hybrida) developed in high RH have previously been shown to have high water loss during leaf dehydration and reduced dark-induced closure resulting in a shorter postharvest life. In this study, the effect of Blight on stomatal function under high RH conditions was investigated. The ability of rose leaves developed under continuous high (90%) or moderate (60%) RH to close their stomata in response to darkness and leaf dehydration assay was studied. Moreover, the level and regulation of ABA in light and darkness in relation to Blight was measured. Our results show that increased Blight proportion improved stomatal function and dark-induced stomatal closure under high RH conditions and that was associated with increased [ABA] in general and a dynamic ABA peak during darkness. Furthermore, increased Blight during the day was associated with the presence of high b-glucosidase activity during night. This indicates that Blight is important as a signal to activate the b-glucosidase enzyme and release ABA during night. Altogether, the improved stomatal function and reduced transpiration in combination with increased [ABA] indicate that preharvest Blight plays an important role in governing stomatal functionality and ABA homeostasis under high RH and can be a useful method to improve postharvest water balance of roses.

Light Spectral Composition Modifies Polyamine Metabolism in Young Wheat Plants

“…Different combinations of blue and red light induced the growth of Salvia miltiorrhiza , which was related to enhanced accumulation of phenolic acids and activation of PAL1 gene expression, the gene encoding phenylalanine ammonia-lyase enzyme, which also has a key role in SA synthesis [ 69 ]. Similarly to our results, the increasing ratio of blue light also decreased the ABA content in rose leaves under light conditions [ 70 ], while far-red supplementation increased ABA levels in barley [ 71 ]. However, due to the widespread use of LED light sources, knowledge of the effects of spectral composition on phytohormone metabolism is an emerging field.…”

Quantitative effects of environmental variation on stomatal anatomy and gas exchange in a grass model

“…While the artificial light intensity and light-darkness cycles are controlled, the contribution of ambient sunlight intensity and day length (DL), average temperature ( T ) and RH vary among seasons in our greenhouse (Supplementary Figure S3A,D–F). Stomatal anatomical traits such as SD and stomatal size are strongly influenced by environmental cues to which the plants are exposed to during development (Casson & Gray, 2008 ; Liu et al, 2018 ; Qi & Torii, 2018 ; Terfa et al, 2020 ). To test the plasticity and variability of stomatal anatomical traits in B. distachyon wild-type plants, we quantified SD and SL as a proxy for stomatal size from 15 individuals grown in different seasons – summer (May to June, n = 5), autumn (October to November, n = 6) and winter (January to February, n = 4) – and correlated these traits with growth conditions ( T , RH and DL; Figure 3a and Supplementary Figure S3A).…”

Quantitative effects of environmental variation on stomatal anatomy and gas exchange in a grass model

“…S3A, D-F). Stomatal anatomical traits such as stomatal density (SD) and stomatal size are strongly influenced by environmental cues to which the plants are exposed to during development (Casson & Gray, 2008; Liu et al, 2018; Qi & Torii, 2018; Terfa et al, 2020). To test the plasticity and variability of stomatal anatomical traits in B. distachyon wild-type plants, we quantified SD and stomatal length (SL) as a proxy for stomatal size from 15 individuals grown in different seasons—summer (May-June, n=5), autumn (October-November, n=6) and winter (January-February, n=4)—and correlated these traits with growth conditions (T, RH and day length (Fig.…”