ISHS Acta Horticulturae 387: III International Protea Research Symposium
EFFECT OF TWO IRRIGATION FREQUENCIES ON WATER STATUS, LEAF DIFFUSIVE CONDUCTANCE AND NET PHOTOSYNTHESIS IN PROTEA EXIMIA GROWN ON GRAVEL SUBSTRATE |
| Authors: | L. Urban, M. Huyghes, M. Montarone |
| Abstract:
Protea eximia seedlings were grown on porphyry substrate in soilless greenhouse culture to study the effect of irrigating 2 and 6 times daily in summer. In both treatments, stomatal regulation appeared very efficient in maintaining constant water content in leaves picked at noon. The highest leaf diffusive conductance, net photosynthesis and production of dry and fresh matter correlated with the highest watering frequency, and conversely. Nonetheless, even the highest watering frequency could not prevent a gradual decrease in leaf diffusive conductance throughout the day. This can be attributed to porphyry's low water retention capacity, or the insufficient frequency of irrigation. Several hypotheses are presented to explain low predawn water potential values (around -0.4 MPa). | |
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