Leaf Anatomical Properties

Prunus L. subgen. Cerasus Mill. (Rosaceae) contains numerous economically
important species, including fruit trees and ornamental plants. This study
compares the leaf anatomy and calcium oxalate crystal types of 98
individuals of 14 Prunus subgen. Cerasus taxa from Turkey. We stained leaf
sections with Safranin-Alcian Blue double stain and mapped calcium oxalate
crystals under light microscope with polarized filter. We used one-way
ANOVA to determine the statistical significance of quantitative data.
Significant quantitative and qualitative data were analyzed using PCoA to
establish relationships among taxa. We observed three different crystal
distribution patterns and three crystal types, finding druses present in
all taxa, while some taxa also have sand or prismatic forms. Most
characters showed high variation. Our analysis shows that vascular bundle,
midrib, upper epidermis and lower epidermis width/length ratios; midrib
epidermis, upper epidermis and phloem cell lengths; upper epidermis and
lower epidermis cell widths and lower cuticle thickness are not
taxonomically useful, while features of the bundle sheath, epidermis cell
surface, phloem fibers, mesophyll layers and angle of blade between the
midrib can be used in conjunction with other characters to distinguish
certain taxa. Overall, PCoA delineated two rough groups, separating P.
avium, P. cerasus and P. mahaleb from the rest of the studied taxa. In
investigating the anatomical variation between different individuals of
these taxa, we found that some features previously used in infraspecific
taxa, such as trichomes, varied sometimes even within an individual,
casting doubt on the wisdom of using these for systematic work in subgenus
Cerasus.