Physiological and histological responses of peach plants grafted onto different rootstocks under calcium deficiency conditions

Abstract

Calcium (Ca) is a crucial element in plant growth and development. Studies focused on the Ca deficiency in Prunus are still limited that triggered us to examine tolerance of peach plants against Ca deficiency using physiological and histological methods. Peach cultivar Rich May plants grafted onto GF 677 and Garnem rootstocks were planted in 10 L pots containing perlite. Plants were irrigated with Hoagland’s nutrient solution. After growth for two months in nutrient solution, plants were exposed to Ca deficient Hoagland solution (except control). Plants were exposed to mineral deficient conditions for 4 months. End of the study, Ca deficiency depressed plant growth, damaged cell membranes and impaired chlorophyll biosynthesis. Concentrations of chlorophyll and chlorophyll precursors were significantly decreased by Ca deficiency in both rootstocks. Cortical cell diameter decreased in both rootstocks under Ca deficiency conditions. However, cortex thickness increased in Garnem and decreased in GF 677. Increments in xylem thickness, xylem conduits length and number of xylem conduits were found in Ca deficient Garnem plants and the parameters decreased in GF 677 under Ca deficiency. Pith autolysis in midrib tissue was not observed in the current experiment. Garnem was found more tolerant rootstock than GF 677 to Ca deficiency. We consider that larger cortical cells and hyperplasy and hypertrophy of xylem vessel elements increased stomatal conductance to uptake more Ca that mitigated Ca starvation in Garnem.