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This study explored possible advantages conferred by the phase shift between leaf phenology and photosynthesis seasonality in a semi-arid Pinus halepensis forest system, not seen in temperate sites. Leaf-scale measurements of gas exchange, nitrogen and phenology were used on daily, seasonal and annual time-scales. Peak photosynthesis was in late winter,(More)
Tobacco (Nicotiana tabacum; C3) plants increase their water use efficiency (WUE) under abiotic stress and are suggested to show characteristics of C4 photosynthesis in stems, petioles, and transmitting tract cells. The tobacco stress-induced Aquaporin1 (NtAQP1) functions as both water and CO(2) channel. In tobacco plants, overexpression of NtAQP1 increases(More)
Co-localization of polyphenols and peroxidase activity was demonstrated in epidermal glands of the waterlily (Nymphaea) by histochemistry. Total phenols, tannins and peroxidase activity were determined quantitatively in plant extracts. Polyphenols were partially identified and were found to consist mainly of hydrolyzable tannins, gallic and tannic acid(More)
Numerous GAST-like genes have been identified in various plant species. All code for small proteins with a conserved C-terminal region in which 12 cysteines are located in exactly the same positions. We have previously identified five gibberellin (GA)-induced GAST1-like genes in petunia, GIP1-5. GIP2 is expressed in elongating zones, and its suppression in(More)
Hyperpolarization-activated K channels (KH channels) in the plasmalemma of guard cells operate at apoplastic pH range of 5 to over 7. Using patch clamp in a whole-cell mode, we characterized the effect of varying the external pH between 4.4-8.1 on the activity of the KH channels in isolated guard cell protoplasts from Vicia faba leaves. Acidification from(More)
Previous studies reveal that the pH of the apoplastic solution in the guard cell walls may vary between 7.2 and 5.1 in closed and open stomata, respectively. During these aperture and pH changes, massive K+ fluxes cross the cellular plasma membrane driving the osmotic turgor and volume changes of guard cells. Therefore, we examined the effect of(More)
The mechanism by which the mature leaf of certain plants reorients its lamina to face the sun throughout the day was studied in Lavatera cretica L. The photoreceptor for this response differs fundamentally from the one involved in the phototropic growth response, by sensing light as a vector, rather than as a difference in luminous flux. The photoreceptor(More)
An advanced non-invasive, field-suitable and inexpensive leaf patch clamp pressure probe for online-monitoring of the water relations of intact leaves is described. The probe measures the attenuated output patch clamp pressure, P(p), of a clamped leaf in response to an externally applied input pressure, P(clamp). P(clamp) is generated magnetically. P(p) is(More)
Guard cells of stomata are characterized by ordered bundles of microtubules radiating from the ventral side toward the dorsal side of the cylindrical cell. It was suggested that microtubules play a role in directing the radial arrangement of the cellulose micro-fibrils of guard cells. However, the role of microtubules in daily cycles of opening and closing(More)
Abscisic acid (ABA), a plant hormone whose production is stimulated by water stress, reduces the apertures of stomatal pores in the leaf surface, thereby lessening transpirational water loss. It has been thought that inhibition of stomatal opening and promotion of stomatal closure by ABA are initiated by the binding of extracellular ABA to a receptor(More)