Improving stomatal functioning at elevated growth air humidity: A review
by Fanourakis D., Bouranis D., Giday H., Carvalho D. R. A., Rezaei N. A., Ottosen C.-O. (2016)
Dimitrios Fanourakisa, Dimitrios Bouranisb, Habtamu Gidayc, Dália R. A. Carvalhoc, Abdolhossein Rezaei Nejadd, Carl-Otto Ottosene
a School of Agricultural Technology, Technological Educational Institute of Crete, GR 71004 Heraklio, Greece
b Plant Physiology and Morphology Laboratory, Crop Science Department, Agricultural University of Athens, Athens, Greece
c Horticulture and Product Physiology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
d Department of Horticultural Sciences, Faculty of Agriculture, Lorestan University, P.O. Box 465, Khorramabad, Iran
e Aarhus University, Department of Food Science, Kirstinebjergvej 10, DK-5792 Årslev, Denmark
In Journal of Plant Physiology 207: 51-60 – https://doi.org/10.1016/j.jplph.2016.10.003 –
• Poor stomatal functioning is the main driver for a deficient plant water status following growth at high RH.
• The reduction in stomatal regulation due to high RH can be ameliorated by manipulations in the rhizospheric or aerial environments.
• ABA mediates genotypic and phenotypic differences in stomatal functioning following cultivation at high RH.
Plants grown at high relative air humidity (RH ≥ 85%) are prone to lethal wilting upon transfer to conditions of high evaporative demand. The reduced survival of these plants is related to (i) increased cuticular permeability, (ii) changed anatomical features (i.e., longer pore length and higher stomatal density), (iii) reduced rehydration ability, (iv) impaired water potential sensitivity to leaf dehydration and, most importantly, (v) compromised stomatal closing ability. This review presents a critical analysis of the strategies which stimulate stomatal functioning during plant development at high RH. These include (a) breeding for tolerant cultivars, (b) interventions with respect to the belowground environment (i.e., water deficit, increased salinity, nutrient culture and grafting) as well as (c) manipulation of the aerial environment [i.e., increased proportion of blue light, increased air movement, temporal temperature rise, and spraying with abscisic acid (ABA)]. Root hypoxia, mechanical disturbance, as well as spraying with compounds mimicking ABA, lessening its inactivation or stimulating its within-leaf redistribution are also expected to improve stomatal functioning of leaves expanded in humid air. Available evidence leaves little doubt that genotypic and phenotypic differences in stomatal functioning following cultivation at high RH are realized through the intermediacy of ABA.