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 CO2 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.
Share and Cite:
Bai, T. , Li, Z. , Song, C. , Song, S. , Jiao, J. , Liu, Y. , Dong, Z. and Zheng, X. (2019) Contrasting Drought Tolerance in Two Apple Cultivars Associated with Difference in Leaf Morphology and Anatomy.
American Journal of Plant Sciences,
10, 709-722. doi:
10.4236/ajps.2019.105051.