Drought-acclimated cotton does not show heterogeneities in stomatal aperture. [Gossypium hirsutum L]
- Univ. of Illinois, Urbana (United States)
The presence of heterogeneities in stomatal aperture distribution has been demonstrated by others using either hormone-treated leaves or chamber grown plants droughted for the first time. The authors sought to determine if such patches' existed in droughted, field-grown plants or in plants that had been acclimated to low leaf water potentials. Cotton (Gossypium hirsutum L.) was grown in the field and subjected to drought by withholding irrigation and rain from 20 days after planting. Stomatal distribution was assayed by briefly exposing attached leaves of 3.5 month-old plants to {sup 14}CO{sub 2} and performing subsequent autoradiography. Stomatal distribution was homogeneous even at the lowest leaf water potentials ({Psi}leaf) of {minus}1.34 MPa. Stomatal patchiness could, however, be induced by uprooting the plant and allowing the shoot to air dry for 6-8 mins. Growth chamber grown plants were acclimated to drought by withholding irrigation for three 5-day cycles. This drought acclimation reduced the {Psi} leaf at which control rates of photosynthesis (measured as CO{sub 2} exchange with an IRGA) could be sustained by {approximately}07 MPa and was accompanied by a similar decline in the {Psi} leaf at which patchiness first appeared. This demonstration that the presence of patches can be altered by treatments causing an acclimation of photosynthesis and that patches do not exist in droughted, field grown cotton leads them to conclude that stomatal heterogeneities do not significantly influence the determination of accurate photosynthetic rates in plants allowed to fully acclimate to drought stress.
- OSTI ID:
- 5517214
- Report Number(s):
- CONF-9107184-; CODEN: PPYSA
- Journal Information:
- Plant Physiology, Supplement; (United States), Vol. 96:1; Conference: Annual meeting of the American Society of Plant Physiology, Albuquerque, NM (United States), 28 Jul - 1 Aug 1991; ISSN 0079-2241
- Country of Publication:
- United States
- Language:
- English
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