Growth, root respiration and photosynthesis of a root-sprouting short-lived herb after severe biomass removal
Abstract
The predominance of short-lived species in disturbed habitats supports the view that generative regeneration is an advantageous strategy under these conditions. However, there are short-lived species that survive the destruction of aboveground biomass and resprout from roots.
Yet, there is only limited knowledge on the effect of injury on the plant growth of individuals regrowing from roots, and nearly no research has been conducted on the physiological regulation of root-sprouting. We experimentally tested the effect of total shoot biomass removal on the growth, root respiration and photosynthesis of the short-lived, root-sprouting herb Barbarea vulgaris (Brassicaceae) to assess the efficiency and importance of the root sprouting ability.
Regenerating plants compensated for the loss of photosynthetic area by producing a higher number of leaves with higher SLA, but we did not observe compensatory photosynthesis, which could potentially counterbalance the loss of photosynthetic area and allow accelerated growth. The root respiration rate significantly decreased immediately after injury and then slightly and consequentially increased.
The belowground biomass of the injured plants decreased by more than four times a month after the injury comparing to the biomass measured immediately after the disturbance. This result suggests the intensive consumption of reserves located in roots, although the root respiration values did not indicate it.
Although we found physiological constraints that limited more vigorous resprouting, we conclude that the root-sprouting ability of short-lived species represents a useful strategy for population persistence in frequently disturbed habitats, in places lacking seed banks or when disturbances occur during less-than-suitable germination conditions.