Changes in soluble carbohydrates during phytochrome-regulated petiole elongation in watermelon seedlings

• Published in: Plant growth regulation 2002-10, Vol.38 (2), p.157-163
• Main Authors: DAMAYANTHI RANWALA, N. K, DECOTEAU, Dennis R, RANWALA, Anil P, MILLER, William B
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Carbohydrates; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Growth and development; Leaves; Morphogenesis, differentiation, rhizogenesis, tuberization. Senescence; Physical agents; Plant physiology and development; Seedlings; Sugar; Vegetative apparatus, growth and morphogenesis. Senescence
• ISSN: 0167-6903; 1573-5087
• DOI: 10.1023/A:1021272902811

Changes in soluble carbohydrate composition and concentration in leavesand petioles of watermelon (Citrullus lanatus (Thunb)Matsum and Nakai cv. Sugar Baby) seedlings during early stages ofphytochrome-regulated petiole elongation were investigated. Watermelon seedlingswere grown in a controlled environment with 350 μmolm^sup -2^ s^sup -1^ photosynthetically activeradiation (PAR) during a 12-h photoperiod. Low intensity end-of-day(EOD) light treatments (for 15 min) of red (R), far-red (FR) and FRfollowed by R (FR/R) were initiated when the seedlings were 14 days old.Seedling growth, and soluble carbohydrate concentration and composition inleaves and petioles were determined after 3 and 6 days of EOD light treatments.The EOD FR increased the petiole length and dry mass partitioned to petioles asearly as 3 days into the treatment. This increased petiole dry mass inFR-treated plants was accompanied with an increase in reducing sugar (glucoseand fructose) concentration in the petioles. Although both leaves and petiolesshowed this effect, the relative increase was greater in petioles than leaves.While the most abundant sugars in petioles were fructose and glucose, thepredominant sugars in leaves were sucrose, raffinose, and stachyose. Thephotoreversion of FR induced changes in growth and sugar concentrations by Rindicates the involvement of phytochrome in these processes.[PUBLICATION ABSTRACT]