Oligomer-based DNA Affymetrix GeneChips representing about one-third of Arabidopsis (Arabidopsis thaliana) genes were used to profile global gene expression in a single cell type, guard cells, identifying 1309 guard cell-expressed genes. Highly pure preparations of guard cells and mesophyll cells were isolated in the presence of transcription inhibitors that prevented induction of stress-induci...

High resolution chlorophyll a fluorescence imaging was used to compare the photosynthetic efficiency of PSII electron transport (estimated by Fq'/Fm') in guard cell chloroplasts and the underlying mesophyll in intact leaves of six different species: Commelina communis, Vicia faba, Amaranthus caudatus, Polypodium vulgare, Nicotiana tabacum, and Tradescantia albifora. While photosynthetic efficie...

Water is the major factor limiting the growth and development of many land plants, and stomata, composed of two guard cells, are the chief gates controlling plants’ water loss. Many environmental and physiological stimuli control stomatal opening, but they all do so through the regulation of guard-cell osmolarity. Increased guard-cell osmolarity leads to the opening of the stomata and decreased...

5-aminolevulinic acid (ALA), a new plant growth regulator, can inhibit stomatal closure by reducing H2O2 accumulation in guard cells. Flavonols are a main kind of flavonoids and have been proposed as H2O2 scavengers in guard cells. 5-aminolevulinic acid can significantly improve flavonoids accumulation in plants. However, whether ALA increases flavonols content in guard cells and the role of fl...

Fructose 2,6-bisphosphate (Fru2,6P(2)) appears to function as a regulator metabolite in glycolysis and gluconeogenesis in animal tissues, yeast, and the photosynthetic cells of leaves. We have investigated the role of Fru2,6P(2) in guard-cell protoplasts from Vicia faba L. and Pisum sativum L. (Argenteum mutant), and in epidermal strips purified by sonication from all cells except for the guard...

We recently showed that treatment with actin antagonists perturbed stomatal behavior in Commelina communis L. leaf epidermis and therefore suggested that dynamic changes in actin are necessary for signal responses in guard cells (M. Kim, P.K. Hepler, S.O. Eun, K.-S. Ha, Y. Lee [1995] Plant Physiol 109: 1077-1084). Here we show that actin filaments of guard cells, visualized by immunofluorescenc...

Microarray analysis was performed on RNA isolated from guard cells that were manually dissected from leaves of Arabidopsis. By pooling our data with those of two earlier studies on Arabidopsis guard cell protoplasts, we provide a robust view of the guard-cell transcriptome, which is rich in transcripts for transcription factors, signaling proteins, transporters, and carbohydrate-modifying enzym...

In this paper, we consider the call admission problem in cellular network with two classes of voice users. In the first part of paper, we introduce a two-threshold guard channel policy and study its limiting behavior under the stationary traffic. Then we give an algorithm for finding the optimal number of guard channels. In the second part of this paper, we give an algorithm, which minimizes th...