Leaf conductance and gas exchange through adaxial and abaxial surfaces in water stressed primary bean leaves

Solárová J., Václavík J., Pospíšilová J.
BIOLOGIA PLANTARUM 19: 59-64, 1977

Klíčová slova: abaxial and adaxial epidermes, stomatal conductance, porometer, water potential
Abstrakt: Abstract. Epidermal conductances for water vapour transfer (g~o), water vapour efflux (E), and net photosynthetic CO2 uptake (Px)through adaxial and abaxial leaf surfaces were estimated simultaneously during the development of water stress in primary leaves of Pt~c~seob, s v~dgaris L. Hydration level was characterized by water saturation deficit (A W.~at), water potential (Tw), osmotic potential (~s) and pressure potential (~rJ). The conductance of the abaxial epidermis was consistently greater than that of the adaxial epidermis, but the response of both surfaces to the increase in water stress corresponded: with increasing water stress epidermal conductances slightly increased, reached a plateau and then sharply decreased (at a rate of about 1.10• l0 -6 cm s -1 Pa -1 and 1.55• 10 -6 ems -1 Pa -1 of ~w for adaxial and abaxial epidermcs, respectively) to very low value. The curves expressing relationship between epidermal conduetances and z] Went, ~w, (/is, as well as t/] were of a similar character. E and P.v through adaxial ~nd abaxial surfaces were practically not affected until water stress reached the "critical" value (~w from --8.2 to --9.2 • l05 Pa). With further increase in water defcit, ho~vever, they sharply decreased. The "critical" value of ~/J,v was the same for both leaf surfaces.
DOI: 10.1007/BF02922488
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