Contrasting Drought Tolerance in Two Apple Cultivars Associated with Difference in Leaf Morphology and Anatomy

Abstract

Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. The present study examined the effects of drought on photosynthesis and water use efficiency (WUE) of two apple cultivars (Honeycrisp and Yanfu 3) that differ in drought tolerance. The results showed that the photosynthetic rate decreased in response to drought stress for both cultivars, with significant differences in intensity. Values for net photosynthetic rate (Pn) in stressed Yanfu 3 remained significantly lower than in the controls, while, for Honeycrisp, only a slight drop in photosynthesis. Similarly, stomatal conductance (Gs), intercellular CO 2 concentration (Ci), transpiration rate (Tr) were markedly reduced in Yanfu 3 under drought stress. However, Honeycrisp showed only minor changes. Under drought stress, the contents of Chl a, Chl b and Chl t in Yanfu 3 were all decreased significantly compared with the control. However, little difference in Honeycrisp was noted between stressed plants and controls. Values for WUE in stressed Yanfu 3 remained higher than in the controls from day 3 until the end of the experiment, while no significant difference was observed in Honeycrisp. Furthermore, Honeycrisp also exhibited superior physiological traits, as indicated by its anatomical and morphological characteristics. Therefore, we conclude that the superior drought tolerance of Honeycrisp was due to its anatomical and morphological characteristics, which possibly contributed to the maintenance of higher photosynthetic capacity than Yanfu 3.

Biochemical, Physiological, and Molecular Aspects of Ornamental Plants Adaptation to Deficit Irrigation

“…Moreover, water use efficiency defines the relationship between photosynthesis and transpiration (P n /E). According to the literature, an increase in WUE under water stress conditions is associated with an adaptation to deficit irrigation, while WUE reduction is associated with sensitive species [42][43][44]. However, plants with low WUE were more competitive in arid environments because they consumed more resources more rapidly thus suppressing competitors.…”

Integrative physiological, metabolomic, and transcriptomic analysis reveals the drought responses of two apple rootstock cultivars

“…is one of the most economically important fruits worldwide, and China is the world’s largest apple producer. Given that most apple trees are grown in arid or semi-arid regions, drought is considered the main environmental factor restricting apple production and thus the development of the apple industry [ 1 , 2 ]. The study on the yield of ‘Fuji’ under drought stress found that moderate drought stress and severe drought stress resulted in a reduction of 9.34% and 22.94% in yield per plant, respectively [ 3 ].…”

Exogenous melatonin alleviated growth inhibition and oxidative stress induced by drought stress in apple rootstock

“…Photosynthesis is one of the physiological processes which is sensitive to environmental stresses (Johnson et al, 2015). It has been reported that drought inhibits photosynthesis through stomatal limitation and non-stomatal limitation (Barchet et al, 2014;Bai et al, 2019). Stomatal closure is one of the earliest responses of plants to drought stress, reducing transpiration and photosynthetic rate (Chaves et al, 2003).…”

“…is one of the most economically important fruits worldwide, with the largest area of cultivation in China (Liu et al, 2012). Most apple trees are grown in arid or semi-arid regions, and drought is considered as the main environmental factor restricting the development and production of apples (Bai et al, 2019). The development of drought resistance is a priority goal in apples.…”