Abstract

COHEN, G; MASCARINI, L  and  XIFREDA, CC. Leaf and stem anatomy and micromorphology in two cut flower cultivars of Rosa hybrida L. Phyton (B. Aires) [online]. 2012, vol.81, n.2, pp.199-204. ISSN 1851-5657.

Micromorphological and anatomical diferences in leaf epidermis and stem xylem of Rosa hybrida 'Lovely Red ' (LR) and 'Rouge Baiser' (RB), commercially grown in Buenos Aires, Argentina, were examined in the lower half of the terminal leafet of 5-foliate leaves and in the basal part of stem, respectively. Digital images obtained from SEM and a phase contrast microscope were used with this purpose. Epicuticular wax, which was present on both sides of the leaves, was more abundant in LR than in RB. Stomata were only present on the abaxial side; they were 111 and 129 per mm² in LR and RB, respectively; the number of epidermal cells was 1025 and 822 mm² in LR and RB, respectively. No significant diferences were observed between cultivars. Lovely Red and RB showed 267 and 308 vessels/mm² stem, respectively, with a total area of 0.87 and 0.64 mm²/mm² stem, respectively, and a vessel area of 0.33 and 0.21 mm², respectively, with significant diferences between cultivars for vessel and total area (p=0.05). As a result, LR showed a smaller vessel number, but they were larger and with a greater total surface area. Terefore, this cultivar might be better than RB for water transport, although more prone to wilting under water stress. Our results complement other studies on cut rose cultivars in terms of the role of the leaf epidermis and xylem vessels in determining diferences in water consumption and transport during the stem life in glasses. Tese results might also contribute to designing post-harvest techniques for optimizing flower quality.

Keywords : Stomata; Xylem vessels; Rose; 'Lovely Red'; 'Rouge Baiser'.

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