The control of leaf water loss by coconut plants cultured in vitro depends on the type of membrane used for ventilation

SummaryThe physiological responses to vessel ventilation of coconut plants cultured in vitro varied with the type of membrane used for ventilation. Plants cultured in vessels ventilated with one of three types of membranes, polypropylene (PP), polyvinyl chloride (PVC) or Whatman filter paper (W) were compared with plants cultured in conventional sealed (S) vessels. Vessel gas exchange, water loss and medium osmolality were greater in vessels ventilated with W compared with vessels ventilated with PP, PVC or S. Plants cultured in W vessels exhibited lower rates of leaf water loss, narrower stomatal apertures and higher leaf abscisic acid (ABA) concentrations than plants cultured in PP, PVC or S vessels. Plants in PP and PVC vessels showed an intermediate behaviour in all these parameters while plants cultured in S vessels exhibited comparatively high rates of leaf water loss, wide stomatal apertures and low leaf ABA concentrations. The results from the plants cultured in W vessels suggest that dehydration ...