Changes in shoot and root adaptations of fibrous-root and taproot crops in response to different drought types: A meta-analysis

Environmental variability induces fluctuating drought stress, significantly affecting crop growth and productivity. However, the overall changes in both shoot and root systems caused by different drought severities and crop types remain unclear. Here, we analyzed the available information on the responses of crop shoot and root systems to different drought stresses. A meta-analysis was conducted using published papers from 1985 to 2023, examining the changes in eight shoot and six root system-related traits in response to different types of droughts. Distinct response patterns were observed under prolonged drought and drying-rewetting cycles. Taproot and fibrous-root crops exhibit a return to near-normal growth after alternating wet and dry conditions. After drought, aboveground growth is dominated by stomatal regulation, reducing aboveground growth to preserve energy. Crops often exhibited rapid growth after drought rewatering to compensate for stress-induced losses and adapt to environmental changes. Root biomass interacted with root morphology to redistribute root biomass in the soil, enhancing plant adaptation to drought stress. This meta-analysis evaluated how crop and drought types influence crop responses to drought, emphasizing the effects of various drought conditions on shoot traits and root plasticity. The findings offer valuable insights for selecting and breeding crops with optimal shoot and root phenotypes, developing drought-tolerant varieties with improved food production potential and promoting efficient water use and informing rational irrigation practices.