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Effects of water stress and high temperature on photosynthetic rates of two species of Prosopis

Paper ID Volume ID Publish Year Pages File Format Full-Text
30553 44486 2008 10 PDF Available
Title
Effects of water stress and high temperature on photosynthetic rates of two species of Prosopis
Abstract

The main aim of this research was to compare the photosynthetic responses of two species of Prosopis, Prosopis chilensis (algarrobo) and Prosopis tamarugo (tamarugo) subjected to heat and water stress, to determine how heat shock or water deficit, either individually or combined, affect the photosynthesis of these two species. The photosynthetic rates expressed as a function of photon flow density (PFD) were determined by the O2 liberated, in seedlings of tamarugo and algarrobo subjected to two water potentials: −0.3 MPa and −2.5 MPa and to three temperatures: 25 °C, 35 °C and 40 °C. Light response curves were constructed to obtain light compensation and light saturation points, maximum photosynthetic rates, quantum yields and dark respiration rates. The photochemical efficiency as the Fv/Fm ratio and the amount of RUBISCO were also determined under heat shock, water deficit, and under the combined action of both stress. Photosynthetic rates at a light intensity higher than 500 μmole photons m−2 s−1 were not significantly different (P > 0.05) between species when measured at 25 °C under the same water potential. The maximum photosynthetic rates decreased with temperature in both species and with water deficit in algarrobo. At 40 °C and −2.5 MPa, the photosynthetic rate of algarrobo fell to 72% of that of tamarugo. The quantum yield decreased in algarrobo with temperature and water deficit and it was reduced by 50% when the conditions were 40 °C and −2.5 MPa. Dark respiration increased by 62% respect to the control at 40 °C in tamarugo while remained unchanged in algarrobo. The photochemical efficiency decreased with both, high temperature and water deficit, without differences between species. RUBISCO content increased in algarrobo 35 °C. Water deficit reduced the amount of RUBISCO in both species. The results of this work support the conclusion that in both Prosopis species, the interaction between high temperature and water deficit affects photosynthesis responses greater than each individual stress, and that the interactive effect is more pronounce in algarrobo than in tamarugo.

Keywords
Prosopis; Photosynthesis; Quantum yield; Water stress; High temperature
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Effects of water stress and high temperature on photosynthetic rates of two species of Prosopis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 92, Issue 2, 21 August 2008, Pages 67–76
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us