caa a22 4500 477109322 CHVBK 20180405111604.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00029282 doi (NATIONALLICENCE)springer-10.1007/BF00029282 Soil moisture and potassium affect the performance of symbiotic nitrogen fixation in faba bean and common bean [Elektronische Daten] [U. Sangakkara, Ueli Hartwig, Josef Nösberger] Potassium (K) is reported to improve plant's resistance against environmental stress. A frequently experienced stress for plants in the tropics is water shortage. It is not known if sufficient K supply would help plants to partially overcome the effects of water stress, especially that of symbiotic nitrogen fixation which is often rather low in the tropics when compared to that of temperate regions. Thus, the impact of three levels of fertilizer potassium (0.1, 0.8 and 3.0 mM K) on symbiotic nitrogen fixation was evaluated with two legumes under high (field capacity to 25% depletion) and low (less than 50% of field capacity) water regimes. Plants were grown in single pots in silica sand under controlled conditions with 1.5 mM N (15N enriched NH4NO3). The species were faba bean (Vicia faba L.), a temperate, amide producing legume and common bean (Phaseolus vulgaris L.), a tropical, ureide producing species. In both species, 0.1 mM K was insufficient for nodulation at both moisture regimes, although plant growth was observed. The supply of 0.8 or 3.0 mM K allowed nodulation and subsequent nitrogen fixation which appeared to be adequate for respective plant growth. High potassium supply had a positive effect on nitrogen fixation, on shoot and root growth and on water potential in both water regimes. Where nodulation occurred, variations caused by either K or water supply had no consequences on the percentage of nitrogen derived from the symbiosis. The present data indicate that K can apparently alleviate water shortage to a certain extent. Moreover it is shown that the symbiotic system in both faba bean and common bean is less tolerant to limiting K supply than plants themselves. However, as long as nodulation occurs, N assimilation from the symbiotic source is not selectively affected by K as opposed to N assimilation from fertilizer. Kluwer Academic Publishers, 1996 common bean nationallicence faba bean nationallicence nodulation nationallicence potassium fertilization nationallicence symbiotic nitrogen fixation nationallicence water stress nationallicence Sangakkara U. Faculty of Agriculture, University of Peradeniya, Sri Lanka aut Hartwig Ueli Institute of Plant Sciences, ETH-Zentrum, 8092, Zürich, Switzerland aut Nösberger Josef Institute of Plant Sciences, ETH-Zentrum, 8092, Zürich, Switzerland aut Plant and Soil Kluwer Academic Publishers; gopher://gopher.wkap.nl 184/1(1996-03-01), 123-130 0032-079X 184:1<123 1996 184 11104 https://doi.org/10.1007/BF00029282 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00029282 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sangakkara U. Faculty of Agriculture, University of Peradeniya, Sri Lanka aut NATIONALLICENCE 700 1- Hartwig Ueli Institute of Plant Sciences, ETH-Zentrum, 8092, Zürich, Switzerland aut NATIONALLICENCE 700 1- Nösberger Josef Institute of Plant Sciences, ETH-Zentrum, 8092, Zürich, Switzerland aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers; gopher://gopher.wkap.nl// 184/1(1996-03-01), 123-130 0032-079X 184:1<123 1996 184 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer