Reiteration in the short lived root-sprouting herb Rorippa palustris: does the origin of buds matter?

Abstract

Regrowth of injured plants occurs from dormant meristems. Its success is known to be dependent on extrinsic factors, such as the severity of an injury and nutrient availability, although little is known about the effect of intrinsic factors. We conducted a growth-chamber experiment with the short-lived root-sprouting herb Rorippa palustris (L.) Besser, where we evaluated the role of bud origin on plant regrowth after disturbance. In particular, we investigated whether shoots sprouting from either axillary or adventitious buds differ in compensatory growth and architecture. We triggered resprouting from axillary versus adventitious buds by two levels of disturbance: (i) removal of the whole aboveground biomass, with axillary buds on the stem base and adventitious buds on roots left intact; and (ii) removal of whole aboveground biomass including axillary buds on the stem base, and only adventitious buds left intact. Despite the fact that the adventitious buds were larger and contained more leaf primordia than axillary buds at the time of disturbance, the latter preferentially resprouted when both types of buds were present. Both axillary and adventitious shoots compensated for lost aboveground biomass; nevertheless, only axillary shoots compensated for fruit production. Shoot reiteration after injury was only partial in both types of shoot; however, adventitious shoots in differed more in their architectural characteristics than axillary shoots did. We confirmed that the output of plant regeneration after disturbance depends also on intrinsic factors such as the origin of the buds.