C0<sub>2</sub> assimilation and photorespiration of grapevine leaves: Responses to light and drought

Authors

  • H. Düring

DOI:

https://doi.org/10.5073/vitis.1988.27.199-208

Keywords:

leaf, stoma, photosynthesis, respiration, transpiration, light, water, drought, resistance, variety of vine

Abstract

The effects of light intensity (photon flux density, PFD) and water stress on ihe gas exchange of grape vine varieties grown under field and glasshouse conditions were studied:
  1. The light compensation point of leaves of field-grown Riesling was determined at 9 μmol quanta · m-2 · s-1, the light saturation of CO2 assimilation (A) was reached at 0.55 mmol quanta · m-2 · s-1. At higher PFD (0.55-2.25 mmol quanta· m-2 · s-1) A increased slightly; this increase is assumed tobe due to the increasing inte r cellular CO2 concentration (ci) at high PFD. Photon yield (A/PFD) decreased with increasing PFD. The rate of photorespiration (RL) ranged from 13.7 to 16.1 % of A (exceptatPFD < 0.17mmolquanta · m-2 . s-1).
  2. Irrigated vines grown in a shaded glasshouse (maximum PFD 400 μmol quanta · m-2 · s-1) exerted lower rates of A, A/PFD and carboxylation efficiency (A/c1) compared to field-grown plants. At high PFD the rate of A of these plants was slightly decreased. The water use efficiency (A/E) was highest in Trollinger (4.7) followed by Riesling (4.6) and Phoenix (3.5 μmol CO2 · mmol H2O-1). Compared to fieldgrown vines RL (% of A) of glasshouse-grown vines increased to 20 %.
  3. Glasshouse-grown vines subjected to water stress (Ψpd = -7.5 bar) showed reduced maximum rates of A ( Amax)· PFD at  Amax was lowered in stressed vines from 725 to 520 ~tmol quanta · m-2 · s-1. At water stress, the A/E ratio was increased in all varieties. The rate of RL was reduced under stress conditions, but to a smaller extent than A. Therefore RL (as % of A) increased to 35-52 %.
  4. 3 d after rewatering stressed vines, stomatal conductance for CO2 (gCO2) and A had not fully recovered from stress; a complete recovery was observed only 5 d after rewatering in Riesling and Phoenix but not in Trollinger.

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Published

2015-12-16

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