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Abstract
Plant Introduction (PI) accessions of spinach (Spinacia oleracea L.) were evaluated for curly top resistance in greenhouse tests at Pullman and in field tests in the Columbia Basin near Basin City, Washington. In greenhouse tests of 185 accessions, possible resistance was observed in 4 that produced single symptomless plants, in 3 that survived long enough to produce some nonviable seed, and in 56 that produced dwarf green plants in which symptom expression and death were delayed. Of the 178 accessions observed in the field, 13 produced 1 symptomless pistillate plant each, 1 produced a single tolerant pistillate plant, and 1 produced 11 symptomless pistillate plants.
Postharvest CaCl2 pressure infiltration improves firmness and storage quality of apples but is still in the experimental stages. Its effectiveness could be increased if we had a better understanding of how Ca affects the tissue at the cellular level. `Golden Delicious' fruit were harvested from a commercial orchard and were pressure-infiltrated with CaCl2 (0%, 2%, or 4% w/v), stored for 6 months at 0C, and then for 7 days at 20C. Between harvest and the end of storage at 20C, the net breakdown of galactolipids and phospholipids decreased with increasing CaCl2 in infiltration solutions. During 0C storage, CaCl2-infiltrated fruit maintained greater concentrations of conjugated sterol lipids, and these lipid classes are thought to be closely associated with the plasma membrane. As membrane lipid alterations are viewed as a central factor in the senescence of fruits, Ca (from postharvest infiltration) may serve a major role in regulating fruit quality losses through its interactions with cell membranes.
Rapid cycling Brassica rapa L. were grown for 7 days in the presence of 11 levels of zinc (Zn) in hydroponic solution culture and evaluated for changes in Zn and glucosinolate (GS) content. Zinc levels were 0.05, 1, 5, 10, 25, 50, 75, 100, 125, 150, and 200 mg·L-1 Zn. Plants grown in solutions with ≥50 mg·L-1 Zn displayed severe Zn toxicity symptoms, grew little, or died and were not subsequently evaluated for GS content. Shoot Zn concentrations increased linearly with increasing Zn treatment levels. Gluconapin, which accounted for nearly 90% of the aliphatic GSs present, was the only aliphatic GS influenced by Zn, and decreased linearly with increasing Zn levels. Accumulation of glucobrassicin and 4-methoxyglucosbrassicin, both indole GSs, responded with a linear increase and quadratically, respectively, to Zn fertility. An aromatic GS, gluconasturtiin, was also influenced by Zn levels in solution, and had a quadratic response to increasing Zn. This suggested that Zn fertility can influence changes in GS that may affect flavor (bitterness, etc.) or medicinal attributes associated with the GS and their breakdown products, as well as elevate the nutritional status of Zn in the leaves of Brassica.