Abstract
Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information was available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N) fixation under conditions of water shortage.
A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (rain-fed conditions) or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique.
Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.
Mungbean Water Use Study
Mungbean as experimental plant was investigated by means of sand culture containing three levels of water to determine the influence of VA mycorrhiza on the host plant growth and its water use. The experimental results showed that inoculating with VA mycorrhiza was beneficial not only to uptake of phosphorus by plant, but also to promoting plant growth.
The amount of water used by mungbean inoculated with mycorrhiza to produce one gram of dry matter was as low as half of that by controlled plant. It was implied that the efficiency of water used by the host plant inoculated with mycorrhiza was increased by 100%.
In this paper, the growth and development of mycorrhizal and non-mycorrhizal plants in three different water levels of sand culture were described. The water consumed by plant growth in the whole growing period was measured and the experimental results were analysed and discussed.
Why This Research Matters
The mungbean water use data is striking: mycorrhizal inoculation cut the amount of water required per gram of dry matter in half. This 100% improvement in water use efficiency is a compelling argument for inoculation in any water-constrained growing environment. Combined with the berseem clover field data on nitrogen fixation, these findings illustrate the dual benefit of mycorrhizal symbiosis for both water and nutrient efficiency.