Testing Drought Stress Memory in Garden Pea (Pisum sativum) Using Controlled Water Loss and Rhizobial Treatment

Drought stress reduces legume growth and can change the plant-microbe interaction that helps support the plant in obtaining nutrients and in recovering. This study examined whether drought exposure and rhizobial inoculation influence growth recovery in Pisum sativum by testing the plants with a drought duration (0 h or 72 h) and Rhizobium inoculant (0 g or 0.05 g). The purpose of this experiment was to determine if drought stress memory and Rhizobium leguminosarum treatment improve stem height following drought, because prior research shows that drought can modify physiological, biochemical, and microbial responses that shape plant performance during later stress. The hypothesis predicted that plants exposed to drought can given rhizobial inoculation, would show greater recovery and higher stem height than uninoculated plants or those without drought exposure. Growth was measured before and after drought, and the change in stem height (cm) served as the dependent variable. A two-way ANOVA tested the effects of drought, inoculation, and their interactions on growth. Drought duration did not significantly affect the change in height, F(1,116)= 0.71, p .400, and rhizobial inoculation also showed no effect on the change in height, F(1,116) = 0.46, p = .500. The interaction between the factors was not significant, F(1,116) = 1.13, p = .289. Mean growth varied widely among individual plants. However, no treatment produced a statistically significant increase. These findings indicate that, under the conditions tested, neither drought exposure nor rhizobial inoculation altered growth recovery. Future work may require longer drought cycles, strain-specific inoculants, or soil microbial controls to detect memory-based responses.