Abstract
Seeds of freshly harvested American ginseng (Panax quinquefolius L.) were stratified at 5°, 10°, 15°, 20°, or 25°C for 6, 8, 10, 12, 14, or 16 weeks. Regardless of the duration of stratification, respiration was usually lowest at 5° and highest at 20°. For temperatures ≥15°, respiration increased with time, reaching a maximum at week 14 and decreasing thereafter. Measurable embryo growth was not detected at 5° and 10°, but at temperatures ≥15°, growth was observed beginning at week 10. By week 16, the greatest embryo growth was attained at 15°, while the greatest percentage of actively growing embryos occurred at 20°. Changes in embryo length closely paralleled those for the embryo: endosperm length ratio. Delaying the initiation of stratification after seed extraction by as little as 10 days reduced embryo growth.
Abstract
Firmness, soluble solids concentration (SSC), starch index, and internal ethylene concentration were measured in the ‘Starkrimson’, ‘Oregon Spur’, ‘Redchief, ‘Royal Red’, and ‘Topred’ strains of ‘Red Delicious’ apple (Malus domestica Borkh) between 130 and 150 days after full bloom (DAFB). Firmness was significantly correlated with DAFB, although there were increases and decreases between 130 and 144 DAFB. SSC increased and was correlated with DAFB. The starch index increased linearly most of the time. There were differences in starch index between the 1983 and 1984 seasons, but no consistent differences among strains. Internal ethylene concentration began to change later than the other characteristics, but was correlated with DAFB in 90% of the comparisons. Fruit attributes that were significantly correlated in 80% or more of the comparisons were firmness with starch index, SSC with starch index, and starch index with internal ethylene. Firmness was correlated with starch index in 90% of the comparisons, SSC in 85%, and internal ethylene in 60%. Superficial scald was consistently correlated only with DAFB. Changes in firmness during storage were not correlated with any of the characteristics measured.
Abstract
Abscisic acid (ABA) levels in seeds of tomato (Lycopersicon esculentum Mill.) fell about 10-fold during fermentation to remove mucilaginous tissue. Imbibing seeds in 20 µg/ml ABA prevented germination and increased ABA content of the seed 15-fold. Subsequent germination in water averaged greater than 90%.
Abstract
As the pistachio (Pistacia vera L. cv. Kerman) nut matured, kernel moisture, respiration rate, and total protein content decreased, while kernel dry weight increased. At optimum maturity, ether-extractable fat and total sugar contents reached a peak. Either or both of these constituents may be useful as a maturity index, in addition to ease of hull separation, to determine optimum harvest date for pistachio nuts. Nut quality was acceptable for harvest during a 2- to 3-week period bracketing the time when the hull separates easily from the shell. Compositional analyses of hulls indicated some limitations on their potential use as animal feed.
Abstract
The effect of pollen of 4 different male palms belonging to Phoenix dactylifera, L. upon the time of maturity and the quality of ‘Zehdi’ date fruit was studied. It was found that pollen from both ‘Ghannami’ and ‘Werdi’ shortened the yellowing time of the Khalal stage and increased the percentage of matured fruit of the ‘Zehdi’ palms. Pollen from both ‘Rissasi’ and ‘Werdi’ resulted in increased fruit setting compared with the other two males. Fruit pollinated with ‘Werdi’ had the lowest percentage of seed weight (the highest edible portion). Fruit pollinated with ‘Ghannami’ pollen had the highest percentage of soluble solids. According to the results obtained in this experiment, it is possible to consider both ‘Ghannami’ and ‘Werdi’ as better male varieties than ‘Rissasi’ and ‘Simsimi’.
Abstract
Olive oil application during an approximate 10-day period following the time at which all drupelets within ‘Mission’ fig fruits had turned red was effective in stimulating fruit growth and maturity. Olive oil was found to yield ethylene, particularly when exposed to solar irradiation, and it is this degradation product that undoubtedly is the stimulative agent.
Abstract
In a 2-year field study, direct-seeded and transplanted tomato cvs. (Heinz 1350, Heinz 1439, Manalucie, Roma) were treated with (2-chloroethyl)phosphonic acid (ethephon) when 10% of the fruit was pink. Ethephon promoted ripening when it was applied to the leaves only, to the fruit only or to the entire plant. Ethephon induced yellowing of the leaves, accelerated ripening 10 days, and concentrated the bulk of the total yield into this harvest. Ethephon induced smaller immature fruit to mature and ripen and thus reduced the average individual fruit weight of harvestable fruit from the large fruited ‘Manalucie’ but not other cultivars.
Abstract
Application of ethephon at 200 to 2,000 ppm was made to the grape cvs. ‘Tokay’ and ‘Emperor’, and at 1,000 ppm to ‘Thompson Seedless’ and ‘Carignane’. The soluble solids were significantly increased in some fruits of ‘Carignane’ but not in the other cultivars. Ethephon treatment resulted in reductions in acidity in some fruits of all cultivars. This increased soluble solids to acidity ratios in some ethephon-treated fruits. An increase in anthocyanin content of the colored berries occurred, but not significantly so in ‘Tokay’. Optimum time for treatment was about 2 weeks after initiation of coloring.
Abstract
When applied to individual greenhouse tomato fruit at ages from 15 to 35 days after anthesis, 2-chloroethylphosphonic acid (Ethrel) at 500 ppm reduced the number of days between anthesis and breaker stage by 7 days. As a result, the early yield from treated fruit was increased considerably with the total yield reaching the same level as the control fruit. No difference in pH and only slight differences in titratable acid or soluble solids between treated and control fruit were observed when compared at the same stage of ripeness. This was also true with respect to respiration and ethylene production of fruit harvested at the breaker stage and stored at 23°C.
Muskmelon [Cucumis melo L. (Reticulatus Group)] fruit sugar content is the single most important consumer preference attribute. During fruit ripening, sucrose accumulates when soluble acid invertase (AI) activity is less then sucrose phosphate synthase (SPS) activity. To genetically heighten fruit sugar content, knowledge of sugar accumulation during fruit development in conjunction with AI and SPS enzyme activities and their peptide immunodetection profiles is needed. Two netted muskmelon cultivars [`Valley Gold' (VG), a high sugar accumulator, and `North Star' (NS), a low sugar accumulator] with similar maturity indices were assayed for fruit sugars, AI, and SPS activity and immunodetection of AI and SPS polypeptides following 2, 5, 10, 15, 20, 25, 30, 35, and 40 (abscission) days after anthesis (DAA). Both cultivars, grown in spring and fall, showed similar total sugar accumulation profiles. Total sugars increased 1.5 fold, from 2 through 5 DAA and then remained unchanged until 30 DAA. From 30 DAA until abscission, total sugar content increased, with VG accumulating significantly more sugar then NS. In both cultivars, during both seasons, sucrose was detected at 2 DAA, which coincided with higher SPS activity than AI activity. At 5 through 25 DAA, SPS activity was less then AI activity resulting in little or no sucrose detection. It was not until 30 DAA that SPS activity was greater than AI activity resulting in increased sucrose accumulation. VG at abscission had higher total sugar content and SPS activity and lower AI activity than NS. Total polypeptides from both cultivars 2 through 40 DAA, were immunodetected with antibodies: anti-AI and anti-SPS. NS had Al isoforms bands at 75, 52, 38, and 25 kDa that generally decreased wtih DAA. One isoform at 52 kDa remained detectable up to anthesis (40 DAA) VG had the same four Al isoforms, all decreased with DAA and became undetectable by 20 DAA. It is unclear if one or all AI isoforms correspond with detected enzyme activity. VG and NS had one SPS band at 58 kDa that increased with DAA and concomitantly with SPS activity. VG had a more intense SPS polypeptide band at abscission then did NS. Thus, netted muskmelon sugar accumulation may be increased by selecting for cultivars with a specific number of AI isoforms, which are down-regulated, and with high SPS activity during fruit ripening.