Effects of bicarbonate and high pH on growth of Zn-efficient and Zn-inefficient genotypes of rice,wheat and rye |
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Authors: | Hajiboland R Yang X E Römheld V |
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Institution: | (1) Departament de Biologia Vegetal. Unitat de Fisiologia Vegetal. Facultat de Biologia, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona, Spain;(2) Departament de Ciències Ambientals. Unitat de Biologia Vegetal. Facultat de Ciències, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Spain |
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Abstract: | We studied the source of the nitrogen used for the growth and resprouting of holm-oak (Quercus ilexL.), and the contribution of nitrogen and carbohydrate root reserves to these processes. Three-year-old plants were grown in a greenhouse with either a sufficient or restricted nitrogen supply for one year. Half the individuals were subjected to shoot excision to provoke resprouting, and a 15N solution was given to these plants and to controls for two months. Nitrogen, Total Non-structural Carbohydrate (TNC), Total Soluble Protein content, and 15N and 13C composition were determined, and histological analyses of woody tissue were performed. Our results show that N-deprived plants used nitrogen from root reserves to support a growth rate similar to that of non-deprived plants. However, deprived plants lost their resprouting capacity in spite of the high TNC accumulation and nitrogen resupply to the soil. After the supply of nitrogen was restored to N-deprived plants, this nutrient mainly accumulated in under-ground organs, which limited the above-ground growth. Resprouting plants first remobilized the nitrogen stored in roots, and thereafter took it up from the solution. The root-crown region did not behave as a specialised reserve organ in three-year-old Quercus ilex L. plants. |
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Keywords: | holm-oak nitrogen absorption nitrogen remobilization nitrogen storage resprouts total non-structural carbohydrates |
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