INFLUENCE OF LEAF AGE, SOIL-MOISTURE, VPD AND TIME OF DAY ON LEAF CONDUCTANCE OF VARIOUS MUSA GENOTYPES IN A HUMID FOREST MOIST SAVANNA TRANSITION SITE
Ij. Ekanayake et al., INFLUENCE OF LEAF AGE, SOIL-MOISTURE, VPD AND TIME OF DAY ON LEAF CONDUCTANCE OF VARIOUS MUSA GENOTYPES IN A HUMID FOREST MOIST SAVANNA TRANSITION SITE, Annals of botany, 74(2), 1994, pp. 173-178
Leaf age effects on the leaf conductance to water vapour diffusion of
the adaxial and abaxial leaf surfaces were measured in the morning and
in the afternoon on 17 different plantain and banana (Musa spp.) geno
types. The irradiance levels increased three-fold while leaf to air va
pour pressure deficit levels increased two- to four-fold from morning
to afternoon during the sampling period in a field site located in the
humid forest-moist savanna transition zone of Nigeria. Conductance va
lues were reduced in older, and senescing leaves relative to the young
and mature leaves both in the morning and in the afternoon. Conductan
ces were higher for the abaxial leaf surfaces than the adaxial surface
and higher in the afternoon than in the morning, with some genotypic
differences. Lower values of leaf conductance to water vapour in the a
fternoon under a short dry spell was sufficiently variable (P greater-
than-or-equal-to 0.05) among the test genotypes to indicate potential
adaptation to transient dry conditions. Differential and relative leaf
conductance adjustments were noted among genotypes experiencing a sho
rt dry spell versus non-limiting soil moisture conditions. Significant
genotypic differences were observed for leaf conductance among the 17
genotypes during the afternoon on the lower leaf surface of younger l
eaves. ABB cooking banana cultivars 'Fougamou' and 'Bluggoe' might be
potentially promising cultivars for transient dry conditions while AAB
plantain 'Bobby Tannap' and one of its hybrids TMPx 582-4 could be ve
ry sensitive to short dry spells according to this evaluation.