Not so hidden anymore: Advances and challenges in understanding root growth under water deficits

Abstract

Limited water availability is a major environmental factor constraining plant development and crop yields. One of the prominent adaptations of plants to water deficits is the maintenance of root growth that enables sustained access to soil water. Despite early recognition of the adaptive significance of root growth maintenance under water deficits, progress in understanding has been hampered by the inherent complexity of root systems and their interactions with the soil environment. We highlight selected milestones in understanding of root growth responses to water deficits, with emphasis on founding studies that have shaped current knowledge and set the stage for further investigation. We revisit the concept of integrated biophysical and metabolic regulation of plant growth, and utilize this framework to review central growth-regulatory processes occurring within root growth zones under water stress at sub-cellular to organ scales. Key topics include the primary processes of modifications of cell wall yielding properties and osmotic adjustment, as well as regulatory roles of abscisic acid and its interactions with other hormones. We include consideration of long-recognized responses for which detailed mechanistic understanding has been elusive until recently, for example hydrotropism, and identify gaps in knowledge, ongoing challenges and opportunities for future research.

Variation in Root Biomass and Distribution Based on the Topography, Soil Properties, and Tree Influence Index: The Case of Mt. Duryun in Republic of Korea

“…This also holds true for other essential resources, such as water and nitrogen [49,50]. Hence, a greater accumulation of fine roots may indicate limited essential resources in the upper slope, leading plants to direct root growth at depths of 10-20 cm for better resource exploration and uptake [51]. Greater root biomass concentration on the upper slope was also observed for pine plantations and cool-temperate forests in Japan [17,52], semi-arid forests and karst ecosystems in China [15,23], and a dry tropical forest in Thailand [53].…”

Celebrating the American Society of Plant Biologists centennial anniversary: A compendium of review articles in plant biology

“… Delmer et al (2024) review major aspects of the 5 major plant cell wall polymers, recognizing “some of the colorful historical figures who shaped cell wall research over the past 100 years” in “The plant cell wall—dynamic, strong, and adaptable—is a natural shapeshifter.” Zhuang et al (2024) highlight the important technologies and key scientists who contributed to research on plant organelles and the endomembrane system over the last century in “A century journey of organelles research in the plant endomembrane system.” Three reviews cover fundamental topics in plant development. In “Reflections on the ABC model of flower development,” Bowman and Moyroud (2024) review the colorful history of the ABC model of flower development, highlighting “unsolved riddles still hidden in the floral alphabet.” Sajeev et al (2024) review the complex and interlinked processes of seed dormancy and germination in “A commitment for life : Decades of unraveling the molecular mechanisms behind seed dormancy and germination.” In their review “Not so hidden anymore: Advances and challenges in understanding root growth under water deficits,” Voothuluru et al (2024) explore biophysical and metabolic constraints affecting the interactions of root systems with the soil environment and plants’ ability to maintain access to soil water under water deficit conditions. Six more articles explore various topics in phytohormones and signaling.…”

Celebrating the American Society of Plant Biologists centennial anniversary: A compendium of review articles in plant biology

“…In Reflections on the ABC model of flower development , Bowman and Moyroud (2024) review the colorful history of the ABC model of flower development, highlighting “unsolved riddles still hidden in the floral alphabet.” Sajeev et al (2024) review the complex and interlinked processes of seed dormancy and germination in A commitment for life: Decades of unraveling the molecular mechanisms behind seed dormancy and germination . In their review Not so hidden anymore: Advances and challenges in understanding root growth under water deficits , Voothuluru et al (2024) explore biophysical and metabolic constraints affecting the interactions of root systems with the soil environment and plants’ ability to maintain access to soil water under water deficit conditions. Six more articles explore various topics in phytohormones and signaling.…”