Growth and Water Relations of Cotton (Gossypium hirsutum), Spurred Anoda (Anoda cristata), and Velvetleaf (Abutilon theophrasti) During Simulated Drought and Recovery

Abstract

Cotton (Gossypium hirsutumL. ‘Coker 315’), spurred anoda [Anoda cristata(L.) Schlecht. # ANVCR], and velvetleaf (Abutilon theophrastiMedik. # ABUTH) were grown in controlled-environment chambers at 29/23 C day/night temperature and 1000 μE·m–2·s–1photosynthetic photon flux density (PPFD). Groups of plants were subjected to water stress by withholding water for 8 days, beginning at 27 days after planting. Cotton reached a lower leaf water potential than spurred anoda and velvetleaf following 8 days of withholding water. Following the drought, plants were rewatered for a 6-day recovery period. Water stress reduced plant height, leaf number, leaf area, total dry weight, stomatal conductance, transpiration, net assimilation rate, and leaf area duration in all species, in comparison with well-watered controls. Water stress decreased partitioning of plant biomass into leaves and increased partitioning into roots. Following rewatering, stomatal conductance and transpiration rates of previously stressed plants recovered to control levels within 28 h. Net assimilation rates of previously stressed spurred anoda also recovered to control levels. After 6 days of recovery, total dry weights and leaf areas of previously stressed plants of all three species remained below those of control plants. The overall effect of the drought and water stress was to delay the time at which spurred anoda and velvetleaf equaled or surpassed cotton in dry weight and leaf area, suggesting that drought early in the growing season under field conditions might increase the competitiveness of cotton relative to the two weeds.