Boron Excess Imbalances Root/Shoot Allometry, Photosynthetic and Chlorophyll Fluorescence Parameters and Sugar Metabolism in Apple Plants
2019
Alexia Oikonomou | Evangelia-Vasiliki Ladikou | Georgia Chatziperou | Theoni Margaritopoulou | Marco Landi | Thomas Sotiropoulos | Fabrizio Araniti | Ioannis E. Papadakis
Boron (B) excess frequently impair plant performances and their productivity; in particular in arid and semi-arid environments. In the present experiment; hydroponically-grown ‘Granny Smith’ apple plants grafted on M9 rootstock were treated with optimal (25 μΜ) or excess (400 μΜ) B for 116 days to evaluate allometric responses of plants to B toxicity and to highlight physiological (photosynthesis and chlorophyll fluorescence) and biochemical (pigment content and sugar metabolism) responses of apple plants to B excess. Boron accumulated principally in top > middle > basal stems and leaves of high-B-stressed plants. Notably, the stem dramatically accumulated a higher level of B, as an attempt to preserve leaves, especially the youngest from further B accumulation. B accumulation seriously affected photosynthesis of younger leaves and caused both stomata (reduced stomatal conductance) and biochemical (reduction of apparent CO<sub>2</sub> use efficiency and pigment content) limitations and altered the photochemistry and energy partitioning in photosystem II. Boron excess altered leaf sugar proportion; increasing the accumulation of non-translocating sugars such as glucose and fructose. Our dataset adds knowledge on the effect of B excess in apple tree and poses serious concerns about the possible effect of B in altering sugar metabolism; which, in turn, can strongly affect fruit production of this worldwide-cropped species.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by Directory of Open Access Journals