Faculty of Agriculture, Chiengmai University, Chiengmai, Thailand.
Responses of apple leaf stomata to environmental factors
Article first published online: 28 APR 2006
Plant, Cell & Environment
Volume 3, Issue 1, pages 13–22, February 1980
How to Cite
WARRIT, B., LANDSBERG, J. J. and THORPE, M. R. (1980), Responses of apple leaf stomata to environmental factors. Plant, Cell & Environment, 3: 13–22. doi: 10.1111/1365-3040.ep11580397
Physics and Engineering Lab., DSIR, Lower Hutt, New Zealand.
- Issue published online: 28 APR 2006
- Article first published online: 28 APR 2006
- Received 20 May 1979; accepted for publication 6 July 1979
Abstract. Stomatal conductances (gs) were measured on the leaves of 3–4 year old Golden Delicious trees and of seedlings of two other cultivars. Measurements were made on container grown trees in the field with a diffusion porometer in 1975 and 1976, and in controlled conditions in a leaf chamber in the laboratory in 1976. Stomatal densities in the Golden Delicious leaves were assessed from scanning electron micrographs. Stomatal density on extension shoot leaves was higher than on other leaf types after June.
The response to irradiance shown by both the porometer and the leaf chamber results could be described by a rectangular hyperbola:
where gmax is maximum conductance and β indicates the sensitivity of gs to photon influx density (Qp). The values of β were in the range 60–90 μmol m−2 s−1.
There was no evidence that apple stomata are sensitive to temperature per se, but gs was reduced by increasing leaf to air vapour pressure deficits (D). There was a linear relationship between gs and D which was not attributable to feed-back to leaf water potential (ψL) as the latter did not affect gs until a threshold of about −2.0 to −2.5 MPa was reached. Conductance generally declined with increasing ambient CO2 concentration.