Compensatory responses in growth and fecundity traits of Sinapis alba L. following release from wind and density stress

Plant responses to short-term stress are usually extrapolated to long-term effects, neglecting examination of the capacity of plants to compensate for stress. We examined the capacity of Sinapis alba plants to compensate for wind and density stress through responses in growth and fecundity traits. Plants were grown under three wind speeds and two densities for three periods (11, 17, or 24 d). During these periods, there were significant losses in growth, thus confirming that plants were stressed. The plants were then allowed to recover in the absence of wind and at reduced density. Following this recovery, measurements of growth, allocation, and reproductive parts were taken. Biomass had been regained in wind-stressed plants relative to control plants, and reproductive attributes were no different, except that flowering time was delayed until 4 d with increased wind. Plants compensated less effectively for density stress with respect to growth and reproduction, but root : shoot allocation was greater in the control plants. Plants were unable to fully compensate for the longest exposure times. We conclude that the effects of short-term stress cannot be extrapolated to long-term effects and that under favorable environmental conditions, the compensatory capacity of Sinapis depends on the severity and duration of the stress.