INFLUENCE DE LA TEMPERATURE DU SUBSTRAT SUR LA CROISSANCE, LE DEVELOPPEMENT ET LE CONTENU EN ELEMENTS MINERAUX DE PLANTS DE TOMATE (CV. VENDOR)

Abstract

The influence of root level temperature on the growth and development of tomato was determined under greenhouse conditions using five substrate temperatures for a period of 3 mo. Heaviest production of root tissue was obtained at lower temperatures (13.8 and 18.6 °C), while best shoot production was obtained with the 23.9 °C treatment. The top/root ratio increased with increased substrate temperature, reaching a maximum at 29.3 °C. Highest yields were produced at 23.9 °C, but more because of larger fruit size than increased fruit set. Higher root level temperatures decreased N and increased K and P content of shoots. Magnesium content was highest at 23.9 °C, while Na was lowest. Shoot Fe, Mn, Zn and Cu concentrations were higher at higher substrate temperatures (29.3 and 33.8 °C).