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- Author or Editor: T. H. Lee x
Lemons (Citrus limon (L.) Burm. f.) were stored for up to 27 weeks at 10°C in air and in an atmosphere of 3 to 5% O2 and 0.1 to 0.2% CO2, with and without an ethylene absorbent. Mold incidence was high in controlled atmosphere (CA) storage where ethylene accumulated, but removal of ethylene reduced its development. CA storage improved retention of green color in lemons.
Ethylene dibromide (EDB) fumigation of fruit of tomato (Lycopersicon esculentum Mill.) reduced red color development in the outer pericarp, although the inner tissues remained unaffected at EDB doses as high as 35 g/m3. Carotene accumulation was enhanced by EDB at 4 g/m3, but at higher doses the carotene content of the tomato pericarp was reduced. Skin puncture force was reduced in green fruit fumigated at 4 g/m3, but not in breaker or pink fruit; higher skin puncture forces were recorded at higher doses for the three fruit maturities tested, EDB stimulated the respiration of preclimacteric fruit, but fruit fumigated just prior to the climacteric showed a normal respiration peak, although a 4 g/m3 treatment resulted in partial climacteric respiratory rise.
Green ‘Valencia’ oranges grafted singly onto seedling trees were placed in a lathhouse to lose chlorophyll and then transferred back to the higher temperatures of the greenhouse where the peel commenced to regreen. The peel carotenoid content of the regreened fruit declined rapidly during the first 4 weeks - a concomitant rise in peel chlorophyll content was recorded. Similar peel pigment changes were measured in regreening orchard-grown ‘Valencia’ oranges. The pulp composition of regreened fruit as measured by soluble solids and acidity showed similar trends to that of the orchard-grown fruit. The data indicate that the grafted fruit provide a convenient system for further studies of the regreening process.
Growth, respiration, and ethylene production patterns of ‘Crenshaw’ and ‘Persian’ cultivars of muskmelon (Cucumis melo L.) were similar to patterns previously established for cantaloupe (‘PMR 45’). From 3 weeks after anthesis the carotenoid content of the pulp of all 3 cultivars steadily increased from the low level characteristic of green tissue. Chlorophyll content decreased throughout the development of the fruits, but in the cantaloupe and ‘Crenshaw’ there was a final loss of chlorophyll during ripening.
Cucumis sativus L. (cvs. Poinsett and Ashley) plants were grown from seed in a growth chamber at a +10C (28/18) or a -10C (18/28) difference (DIF) between day temperature (DT) and night temperature (NT) on a 12-hour photoperiod for 24 days prior to ozone (O3) fumigation (3 hours at 0.5 umol·mol-1). Negative DIF, compared to +DIF, reduced plant height, node count, fresh weight, dry weight, and leaf area in both cultivars. Photosynthetic rate (Pn), chlorophyll concentration, and variable chlorophyll fluorescence (Fv) were lower and O3 injury and polyamine concentrations were higher at -DIF than at +DIF. Ozone fumigation generally increased leaf concentration of polyamines and reduced Pn, stomatal conductance, and chlorophyll fluorescence. `Poinsett' generally had a higher specific leaf mass and higher concentrations of chlorophyll a and polyamines than did `Ashley', but there was no cultivar difference in O3 injury, growth response, Pn, or stomatal conductance.
Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] has the potential for increased use as a turfgrass species due to its low maintenance and water conservation characteristics. This study was conducted to estimate diversity and relationships among naturally occurring buffalograss genotypes based on the nuclear genome, using sequence-related amplified polymorphism (SRAP) markers. The 56 genotypes studied represented five ploidy levels collected from diverse geographic locations in the North American Great Plains. In addition, blue grama [Bouteloua gracilis (H.B.K.) Lag. Ex Steud.] and perennial ryegrass (Lolium perenne L.) were included as outgroups. Twenty-five combinations of forward and reverse primers were used. Ninety-five intensively amplified markers were scored and used to infer diversity and relationships among the genotypes. All buffalograss genotypes were discriminated from each other with similarity values ranging from 0.70 to 0.95. Principal component analysis (PCA) suggested that the 56 genotypes could be reduced to 50 due to high similarity levels among some of the genotypes. The distance between buffalograsses, blue grama, and perennial ryegrass were consistent with current taxonomical distances. This research indicates that SRAP markers can be used to estimate genetic diversity and relationships among naturally occurring buffalograss genotypes.