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Kevin M. Folta and Kayla Shea Childers

laboratory plant ( Arabidopsis thaliana ) and applied plant biology. It was presumed that these sensory pathways were conserved among plants and that translation of arabi-centered paradigms would translate cleanly to other plants. Certainly, shining examples

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T. Casey Barickman, Dean A. Kopsell, and Carl E. Sams

. Because ABA is a product of the carotenoid biosynthetic pathway, we hypothesized that applications of ABA treatments would have a positive impact on leaf chlorophylls and carotenoids. Therefore, applications of ABA treatments may also have a positive

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Morris Lieberman and Alice Kunishi

Abstract

Ethylene, a “broad spectrum” physiological agent in plant metabolism, has excited new interest in recent years following accumulation of evidence which places it in the category of a plant hormone. Every plant tissue produces ethylene and is influenced by ethylene at some stage in its life cycle; yet the origin of ethylene in plants and the pathways of its biosynthesis are for the most part still unknown. There has been much activity in this field in the past 6 years, and a great advance has been made in the discovery of a precursor of ethylene in metabolism (10). A number of ethylene-forming model systems were developed and these have led to proposals of enzymes, intermediates and pathways for ethylene biosynthesis in vivo. In this discussion I am going to consider these model systems and suggested pathways and evaluate their pertinance to ethylene biosynthesis in tissues.

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Naoki Yamauchi and Alley E. Watada

Degradation of chlorophyll in spinach (Spinacia olearacea L. cv. Hybrid 612) appeared to be regulated through the peroxidase-hydrogen peroxide pathway, which opens the porphyrin ring, thus resulting in a colorless compound. This conclusion was arrived at from the analysis of chlorophylls (Chls) and their metabolizes by HPLC and of enzyme activities catalyzing the degradative reactions. Chls decreased at 25C but not at 1C. The chlorophyll oxidase pathway was not active, as noted by the lack of accumulation of a reaction product named Chl a-1. Lipid peroxidation increased with storage, but the products of the reaction. did not degrade chlorophyll, as noted by the lack of increase in Chl a-1. Chlorophyllase activity increased, but chlorophyllide, the expected product of the reaction, changed minimally during senescence. Ethylene at 10 ppm did not alter the pathway that degraded chlorophyll in spinach.

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Arthur A. Schaffer, Marina Petreikov, Daphne Miron, Miriam Fogelman, Moshe Spiegelman, Zecharia Bnei-Moshe, Shmuel Shen, David Granot, Rivka Hadas, Nir Dai, Moshe Bar, Michael Friedman, Meir Pilowsky, Nehama Gilboa, and Leah Chen

The carbohydrate economy of developing tomato fruit is determined by wholeplant source–sink relationships. However, the fate of the imported photoassimilate partitioned to the fruit sink is controlled by the carbohydrate metabolism of the fruit tissue. Within the Lycopersicon spp. there exists a broad range of genetic variability for fruit carbohydrate metabolism, such as sucrose accumulation and modified ratios of fructose to glucose in the mature fruit and increased starch synthesis in the immature fruit. Metabolic pathways of carbohydrate metabolism in tomatoes, as well as natural genetic variation in the metabolic pathways, will be described. The impact of sink carbohydrate metabolism on fruit non-structural carbohydrate economy will be discussed.

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John C. Majsztrik, Elizabeth W. Price, and Dennis M. King

and vegetable production, especially crops that are susceptible to fluctuating soil moisture levels, such as tomato ( Solanum lycopersicum ), peach ( Prunus persica ), and grape ( Vitis vinifera ). Nonagricultural benefit pathways. As part of our

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Matthew L. Richardson, Catherine J. Westbrook, David G. Hall, Ed Stover, Yong Ping Duan, and Richard F. Lee

pathway for infection by the bacterium Xanthomonas citri subsp. citri , which causes Asiatic citrus canker and reduces the quality and quantity of fruit ( Chagas et al., 2001 ; Christiano et al., 2007 ; Hall et al., 2010 ). Current management of the

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Jessica G. Barb, Dennis J. Werner, and Robert J. Griesbach

, 1991 ; Fick, 1976 ; Hawkins and Dane, 2001 ; Pahlavani et al., 2004 ; Tyrach and Horn, 1997 ) because several key enzymes in the flavonoid biosynthetic pathway have multiple precursors. The genus Stokesia (J. Hill) Greene is a member of the

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Ying Ma, Xinduo Li, Zhanying Gu, and Jian’an Li

. Combining TiO 2 application with nutrient supplementation may strengthen the stress tolerance in plants. Cultivation conditions, secondary metabolism, and pigment synthesis pathways could be manipulated to improve the expression of genes related to

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Nanqing Liu, Shaoyan Lin, and Bingru Huang

on CAT. This study demonstrated that GB and Spd differentially affected OA and activated different antioxidant defense pathways, protecting plants from drought damages in creeping bentgrass. The underlying molecular mechanisms of how GB and Spd