A SURVEY OF PREHARVEST CONDITIONS AFFECTING THE REGULATION OF WATER LOSS DURING VASE LIFE

Vase life (VL) tests on cut roses obtained from commercial sources were conducted at FloraHolland. Water stress symptoms were the most important criterion terminating VL in 46 out of 50 assessed cultivars. These symptoms appear when water loss exceeds water uptake. Inadequate control of water loss during postharvest period, therefore, limits VL. Here we review the link between preharvest conditions and the control of water loss in the postharvest phase, and discuss how the VL evaluation protocol may affect the outcome. Key cultivation-related environmental factors affecting the stomatal functionality are a low evaporative demand, as a result of either high air humidity or low air velocity, and continuous light (CL). Low evaporative demand weakens stomatal functionality considerably more than CL; the combination of both factors is detrimental. Reduced foliar abscisic acid concentration underlies the attenuated stomatal responsiveness following cultivation under either condition. For a given batch of roses the incidence of water stress symptoms during the VL may be either accelerated or delayed depending on the evaluation protocol. For instance, assessing the effect of high humidity during growth by using long stems with several leaves leads to short VL, but when e.g., short stem roses are evaluated VL may not be affected. This resulting shift in both the phenotype and the relationship between phenotype and preharvest conditions highlights the necessity for common standards in VL analysis. Although our understanding of how preharvest conditions induce adverse water relations during VL has developed significantly, the gap between phenotype and genotype remains particularly large.