The Effect of Root Temperature and NO−3/NH+4 Ratio on Strawberry Plants. I. Growth, Flowering, and Root Development1
- Ruth Ganmore-Neumann and
- U. Kafkafi2
The purpose of this work was to study the effect of various NO−3/NH+4 ratios in the nutrient solution at various root temperatures on strawberry (Fragaria ananassa) plants. The results could lead to a suitable NO−3/NH+4 ratio of the fertilizer solution to be applied in field-grown strawberry plants in different seasons on sandy soils.3 Strawberry plants were selected for uniformity and transferred individually to a 1 L container through which the nutrient solution was flushed at a rate of 1 L/h. The total N concentration was 7 me/L. Five ratios of NO−3/NH+4, 7/0, 5/2, 3.5/3.5, 2/5, and 0/7, respectively, were used, each at four root temperatures (10, 17, 25, and 32°C). Constant NO−3/NH+4 ratio, constant total nutrient concentration, and constant pH (6.2) were maintained for 8 weeks. There is a general decline in root growth with increasing root temperature when a single source of N is supplied. This decrease is followed with a decrease in the sugar concentration of the roots. At 32°C root temperature gradual increase in the NH+4 fraction in the nutrient solution is followed by gradual deterioration of the plants to a complete death at 100% NH+4. This death is related to the depletion of sugars and possible shortage of oxygen in the root cells due to NH+4 metabolism in the root.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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