Effect of P‐deficiency on photoassimilate partitioning and rhythmic changes in fruit and stem diameter of tomato (Lycopersicon esculentum) during fruit growth

• Published in: Journal of experimental botany Vol. 54; no. 392; pp. 2519 - 2528
• Main Authors: Fujita, K., Okada, M., Lei, K., Ito, J., Ohkura, K., Adu‐Gyamfi, J. J., Mohapatra, P. K.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-11-2003; OXFORD UNIVERSITY PRESS; Oxford Publishing Limited (England)
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Biomass; Desiccation; Economic plant physiology; Flowers - growth & development; Flowers - radiation effects; Fructification and ripening; Fructification, ripening. Postharvest physiology; Fruits; Fundamental and applied biological sciences. Psychology; Growth and development; Key words: Fruit and stem diameter; Kinetics; Leaves; Light; Lycopersicon esculentum - growth & development; Lycopersicon esculentum - radiation effects; micro‐morphometry; Nitrogen - metabolism; partitioning; Phosphorus; Phosphorus - deficiency; Photosynthesis; Plant anatomy; Plant growth; Plant Leaves - growth & development; Plant physiology; Plant physiology and development; Plant roots; Plant Roots - growth & development; Plant Stems - growth & development; Plant Stems - radiation effects; Plant Transpiration; Plants; Reference Values; Research Papers: Regulation of Growth, Development and Whole Organism Physiology; Time Factors; tomato; Transpiration; Vegetative and sexual reproduction, floral biology, fructification; Isotope labelling; Resource allocation; tomato; Inorganic element; Time variation; Stem; Dicotyledones; Angiospermae; Lycopersicon esculentum; Solanaceae; Diameter; Fruit and stem diameter; Fruit; Nutrition; Deficiency; Stomatal conductance; Phosphorus; Circadian rhythm; Source sink relationship; Spatial distribution; Vegetable crop; micro-morphometry; Nutrient; partitioning; Spermatophyta; Gas exchange; Photosynthesis; Fructification
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erg273

Tomato (Lycopersicon esculentum) plants were grown in liquid culture inside the greenhouse of Hiroshima University, Japan. At the first fruiting stage, P was withdrawn from the rooting medium for a period of 19 d and its effect was studied on photosynthesis, stomatal conductance, transpiration, partitioning of 13C and 15N, P contents of various organs, and changes in stem and fruit diameter of the plant in order to identify the mechanism of resource management on the part of the plant at low P. Compared to the control, P‐deficiency treatment decreased biomass growth of all organs except the roots. The treatment also depressed leaf photosynthesis, stomatal conductance and diameter of fruit and stem after a lag period of about 1 week. The stem diameter of the plant shrank during daytime and expanded during the night; the adverse effect of P‐deficiency on stem diameter change was more evident during the night than the day. The circadian rhythm in fluctuations of diameter was less manifested in the fruit compared with the stem. P‐deficiency induced daytime shrinkage and reduced night expansion of fruit. However, within the plant, P‐deficiency encouraged partitioning of 13C, 15N and P into the fruit at the cost of autotrophic organs such as leaves and the upper parts of the stem. The results were discussed in the light of a plausible effect of P‐deficiency on water relations of the plant. It is concluded that, in spite of the preference in partitioning of C and N received within the plant parts, assimilate flow into the fruit is limited at low‐P compared with the control, owing to the restriction in fruit expansion.