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Abstract
The surface meshwork of tissue, commonly referred to as the “net,” of fruit of Cucumis melo L. cv. PMR-45 is an elaborate system of lenticels. Lenticellar tissue is derived from a subepidermal periderm. Cork cells, which comprise the complementary tissue of lenticels, protrude through the surface fissures which develop as the fruit enlarges. It is suggested that cork cells of the net and of the periderm contribute to resistance to mechanical injury of the fruit; that gaseous exchange is facilitated by lenticellar net development; and that resistance to disease is enhanced by the presence of a surface cuticle and by the development of cork cells with suberized walls.
The objective of this study was to measure effects of late-season water stress on fruit yield, size, quality, and color of an early-maturing navel orange cultivar, Citrus sinensis (L.) Osbeck ‘Beck-Earli’. Three irrigation regimes were initiated in August in the southern San Joaquin Valley of California in 2006, 2007, and 2008. Increasing levels of water stress resulted in decreasing midday shaded leaf water potential (SLWP) ranging from –1.4 MPa in early September to a minimum of –2.5 MPa at harvest. Generally, over the course of the 3 years, late-season water stress decreased fruit grade and increased soluble solids concentration (SSC), titratable acidity (TA), the BrimA index, and orange color. Fruit juiciness and SSC:TA ratios were unaffected by late-season water stress. The intensity of the water stress in 2007 decreased fruit yield by number and weight and decreased the percentage of large fruit. When trees exposed to 2 years of late-season water stress were fully irrigated the next year, fruit yield and quality were similar to trees that had not experienced late-season water stress for the 3 years of the study.
Abstract
(2-Chloroethyl)phosphonic acid (ethephon) at 250 ppm controlled bud and flower abscission but not young pod abscission of ‘Dark Red Kidney’ bean. Leaf abscission was unaffected, intemodal elongation was temporarily retarded, and the number of seeds but not the number of pods produced exceeded that of untreated plants but the difference in seed production was not significant. Treatment with 500 ppm ethephon resulted in a pattern of abscission similar to that of untreated plants. At higher concentrations (1000 and 2000 ppm) abscission of reproductive structures and of leaves was promoted. Seed production, seed maturity, and seed size were reduced. New leaves were pendant and were smaller than those of untreated plants.