Investigation of Stomata in Cut ‘Master’ Carnations: Organographic Distribution, Morphology, and Contribution to Water Loss

Abstract

<jats:p>Leaf stomata are the main channels for water loss of plants including cut flowers. In this study, we investigated the organographic distribution, morphological characteristics, light–dark response, and water loss contribution of stomata in cut carnations (<jats:italic>Dianthus caryophyllus</jats:italic> L. ‘Master’), which are prone to typical water deficits despite a few and small leaves. Stomata were observed in the upper and lower leaf epidermis, stem surface, abaxial bract epidermis, and abaxial sepal epidermis. Stomatal density (SD) on the stem surface was the highest and significantly greater than that on the upper and lower leaf and abaxial bract epidermis. The sepal epidermis had the lowest SD and the smallest stomata whereas the upper leaf epidermis had the largest stomata. Changes in the water loss rate increased in the light and decreased in the dark in both intact and leaves-removed cut carnations. The water loss rate of the former was greater than that of the latter. However, the water loss rate for the stem-only cut carnations had weak change rhythms and was much lower than that for the intact and leaves-removed cut carnations. These findings demonstrate the differential contributions of stomata in leaves, stems, and floral organs to water loss, and help to elucidate further the mechanism underlying postharvest water deficit in cut carnations.</jats:p>

The Role of Water Relations and Oxidative Stress in the Vase Life Response to Prolonged Storage: A Case Study in Chrysanthemum

“…Although not supported by the obtained data so far, Körner et al (2021) [29] have pointed out that there is an inherent limit in decreasing leaf stomatal conductance without a yield penalty. The present results in combination with data on carnation [11] suggest that stem transpiration is undoubtedly an additional trait of high interest towards improved cut flower water relations, at least in some cut flower species. Including it in breeding programs will, thus, partly alleviate the pressure for selection of the low leaf weight loss trait, which may eventually limit productivity.…”

“…In addition, the effect of long-term storage on the transpiration of non-leaf tissues (stem, flowers) has not been previously addressed. Their contribution to whole-cut flower transpiration can be sizeable in some cut flower species (i.e., carnation and chrysanthemum) [8,11] and increases as stomata close [8,12]. During the supply chain, cut flowers often experience dry periods [7,8,13].…”

Variation in Petal and Leaf Wax Deposition Affects Cuticular Transpiration in Cut Lily Flowers

“…As the occurrence of stomata, water loss occurred mainly through the leaf tissues in the intact cut flowers. When most of the stomata closed, leaves were still the main parts for water loss in roses, but not in carnation or chrysanthemum ( Lin et al, 2020 ; Tsaniklidis et al, 2020 ; Fanourakis et al, 2021 ). These studies considered stomatal transpiration as the main pathway for water loss in cut flowers.…”

Combined heat and water stress leads to local xylem failure and tissue damage in pyrethrum flowers

“…Water loss across the floral cuticle may protect gametes from thermal injury in a similar way. Floral organs tend to have no or fewer stomata ( Lipayeva 1989 ; Feild et al 2009 ; Lambrecht et al 2011 ; Zhang et al 2018 ; Lin et al 2020 ) and a greater conductance to water vapor than leaves once stomata are closed ( Nobel 1977 ; Buschhaus et al 2014 ; Cheng et al 2019 ; Bourbia et al 2020 ; Cheng et al 2021 ), with some exceptions ( Whiley et al 1988 ). This indicates that in many species, floral cuticles are a weaker barrier to water loss and/or that floral stomata are leakier compared with those of leaves.…”