Summary of Mitigation of alkaline stress by arbuscular mycorrhiza in zucchini plants grown under mineral and organic fertilization
Mitigation of Alkaline Stress in Zucchini Through Mycorrhizal Inoculation
A greenhouse experiment tested the mitigation of alkaline stress in zucchini (Cucurbita pepo L.) during spring–summer 2009. Researchers evaluated whether arbuscular-mycorrhizal (AM) inoculation using Glomus intraradices could improve plant growth under alkaline conditions and how fertilization type affects AM development.
Effects of Alkaline Conditions on Zucchini Growth
Zucchini plants were grown in sand culture at two pH levels (6.0 and 8.1) with either organic or mineral fertilization. High-pH nutrient solutions contained additional NaHCO3 and CaCO3 to simulate alkaline stress. Increasing NaHCO3 concentration from 0 to 10 mM significantly reduced plant growth, leaf SPAD index, CO2 assimilation (ACO2), and nutrient content (N, P, Ca, Mg, Fe, Mn, Zn).
Role of Mycorrhizal Inoculation in Stress Mitigation
AM-inoculated (+AM) plants maintained higher yields, biomass, SPAD index, and net CO2 assimilation compared to non-inoculated (–AM) plants under alkaline stress. The improved performance of +AM plants is linked to better nutrient management, with higher P, K, Fe, Mn, and Zn and lower Na accumulation, highlighting the importance of mitigation of alkaline stress via AM fungi.
Impact of Fertilization on AM Colonization and Yield
Organic fertilization promoted higher AM root colonization (35.7%) than mineral fertilization (11.7%). However, mineral-fertilized plants achieved the highest yield and biomass due to superior nutritional status (N, P, Ca, Mg), leaf area, SPAD index, and CO2 assimilation. This shows that fertilization type interacts with AM inoculation to influence both plant growth and mitigation of alkaline stress.
