Ecophysiological responses to drought followed by re-watering of two native Chilean swamp forest plants: Myrceugenia exsucca (DC.) O. Berg and Luma chequen (Molina) A. Gray

Abstract

Myrceugenia exsucca (DC.) O. Berg and Luma chequen (Molina) A. Gray are two predominant species of Myrtaceae
from the swamp forest which are strongly threatened by destruction of their habitat. Conservation programs include the
creation of new protected areas which often have different environmental conditions respect their natural habitat. The
drought tolerance and the capability to restore their physiological performance after stress relief are characteristic of great
importance for the successful conservation programs on these kinds of plants. Understanding how these plants respond
to episodic drought and watering pulse was the principal aim of this work. In this sense, water relations, soluble sugars,
pigments and photosystem II (PSII) performance were studied. In general the water relationships were less affected by
drought in L. chequen than in M. exsucca which was consistent with a higher maintenance of photochemical quenching
(qP) in the first one. In addition, L. chequen exhibited complete recovery of water potential and maximum PSII efficiency
and increasing the proportion of photochemical processes and soluble sugars related with a higher photosynthetic recovery.
Contrastingly, M. exsucca was unable to recover its water potential and the proportion of open reaction centers of PSII
under re-watering indicating a lower capacity of recovery. These results shown different capabilities to cope and reestablish
physiological performance after water scarcity episode between these two native chilean swamp forest plants. We hope that
these results will be important for conservation and re-vegetation managements programs.