External color, length, diameter, fresh weight, C02 production, internal C2HA concentration, flesh firmness, soluble solids concentration (SSC), flesh color, and seed cavity diameter were measured during fruit growth and maturation of seven melon cultivars (Cucumis melo L., Inodorus Group, Naud. cv. `Amarelo', `Golden Beauty Casaba', `Honey Dew', `Honey Loupe', `Juan Canary', `Paceco', and `Santa Claus Casaba') of known age. There was no increase in C02 production either during ripening (e.g., loss of firmness and increased SSC) or with increasing C2H4 levels in fruit from any of the seven cultivars. There was a significant decline in respiration only at the second sampling date, which ranged from 14 to 18 days after anthesis. Respiration measured 1 week later was substantially higher and was followed by a general decline. This post 14- to 18-day rise in respiration was not a climacteric since it occurred well in advance of other ripening characteristics, e.g., loss of firmness, increase in SSC, or rise in internal C2H4. The increase in internal C2H4. coincided with or followed attainment of full fruit size, while flesh softening and the rapid rise in SSC preceded the rise in internal C2H4, concentration. Respiration declined from 67 to 18 ml CO2/kg per hour by day 43 in all cultivars, except `Honey Dew' and `Honey Loupe'. Respiration in `Honey Loupe' remained above 23 ml CO2/kg per hour and showed a rise to 32 ml/kg per hour on day 53. Respiration in `Honey Dew' did not fall below 18 ml CO2/kg per hour until day 53. As with internal C2H4 levels, there was no correlation between changes in and any marked change in the other signs of ripening that were measured.
Trends in chlorophyll fluorescence for `Starking Delicious', `Golden Delicious' and `Law Rome' apple (Malus ×domestica Borkh.) fruit were examined during the harvest season, during refrigerated-air (RA) storage at 0 °C, following RA and controlled-atmosphere (CA) storage, and during a poststorage holding period at 22 °C. Fluorescence parameters of minimal fluorescence (Fo), maximal fluorescence (Fm), and quantum yield [(Fm-Fo)/Fm, otherwise denoted as Fv/Fm] were measured. During `Starking Delicious' fruit maturation and ripening, Fv/Fm declined with time, with the rate of decline increasing after the ethylene climacteric. During RA storage, all fluorescence parameters remained constant for approximately 2 weeks, then steadily declined with time for `Starking Delicious' fruit. Superficial scald was detected after Fv/Fm had declined from an initial value of 0.78 to ≈0.7. Fv/Fm was consistently higher for CA-stored fruits than for RA-stored fruits. We were able to resegregate combined populations of “high-quality” (CA) and “low-quality” (RA) `Law Rome' fruit with 75% accuracy using a threshold Fv/Fm value of 0.685, with only 5% RA-stored fruit incorrectly identified as being of high quality. During a poststorage holding period, Fo, Fm, and Fv/Fm correlated well with firmness for `Starking Delicious', but not for `Golden Delicious' fruit, which were already soft. Fo and Fm were linearly correlated with hue angle for 'Golden Delicious' fruit, decreasing as yellowness increased. The accuracy, speed of assessment, and light-based nature of fluorescence suggests that it may have some practical use as a criterion to assist in sorting apple or other chlorophyll-containing fruit or vegetables on commercial packing lines.
Apple fruit abscission shortly before harvest is a frequent, recurring problem, thereby reducing potential yield. The synthetic auxin 2 (2,4-dichlorophenoxy) propionic acid (2,4-DP) was evaluated for its effect on reducing fruit drop and influencing ripening of `Braeburn' apples, in the High Valley region of Río Negro, Argentina (38°56'S, 67°59'W). Thirteen-year-old apple trees grafted on MM 111 rootstock were sprayed on 4 Mar. 2005, at 162 days after full bloom (DAFB) with 2,4-DP at doses of 0.05% and 0.10% (v/v), applied with an airblast sprayer, until runoff. Each tree was trained to palmette and planted in a single row from north to south with spacing of 2.3–4.0 m. The following measurements were performed: a) accumulated fruit drop, twice per week and b) maturity indices, weekly. Samples of uniform-size fruits were assessed for maturity (n = 20 per date and treatment), from 167 (commercial harvest) to 195 DAFB. On 23 Mar. (at 181 DAFB), cumulative fruit drop for control treatment was 19.9%, whereas 2,4-DP significantly reduced it to 4.90% and 2.94% at 0.05% and 0.10% (v/v), respectively. Reduction in the drop was also significant later, and 2,4-DP at both doses controlled drop comparably. The synthetic auxin did not affect fruit quality and maturation, based upon flesh firmness, starch degradation, and soluble solids concentration. We conclude that 2,4-DP is an effective drop control compound and it is useful as a management tool to increase yield by reducing fruit abscission and to extend the harvesting window of `Braeburn' apples, since it does not affect ripening. Delaying harvest may provide flexibility for scheduling of labor, fruit processing and packaging, cold storage, and marketing.
Growth and maturation of `Pink Lady' (Malus domestica Borkh.) apples with special emphasis on ethylene biosynthesis and color development were monitored in Western Australia during 2002-2003. Changes in fruit growth, respiration rate, ethylene production, anthocyanin accumulation and development of red blush were evaluated between 60 days after full bloom (DAFB) and commercial harvest (191DAFB). Fruit diameter, length and fresh weight showed the typical single sigmoid growth curve, with linear increases until 158 DAFB. High respiration rate and ethylene production were recorded 60 DAFB followed by rapid decrease until 144 DAFB and then a steady increase, which peaked between 172 and 179 DAFB. Red blush on the fruit surface showed steady increase from 167 DAFB and corresponded to concomitant decrease in hue angle. Total anthocyanin increased from 167 DAFB till harvest and synchronized with increasing ethylene and maturity of apples. There were significant (P ≤ 0.001), direct linear relationships between ethylene production and total anthocyanin (r = 0.63, y = 7.6032x + 2.4756), total anthocyanin and red blush (r = 0.74, y = 0.5082x -1.54). Significant (P ≤ 0.001) negative direct linear relationships between total anthocyanin and hue angle (r = -0.89, y = -0.5973x + 110.14), and ethylene and hue angle (r = -0.69, y = -5.37x + 109.60) were recorded. Increasing anthocyanin content and red blush also coincided with decreasing daily temperatures in the orchard. Reduction in fruit firmness and acidity and increase in TSS from 167DAFB were good indicators of advancing maturity of apples. Our experimental results indicate that red blush in `Pink Lady' apples develops a few weeks before harvest and is regulated by ethylene biosynthesis and temperature.
Succinic-acid-2,2-dimethylhydrazide (SADH) applications hastened the maturity of peach fruit when trees were sprayed during fruit growth stages I, II and III. The greatest hastening of fruit maturity was evident with high concn of SADH (4000 and 8000 ppm) applied between the mid-point and the end of stage I. The optimum concn during stage II for hastening maturity was 1000 ppm. Applications of SADH in stage III hastened fruit color development but had little effect on other indices of maturation. Five of 6 SADH analogues were effective in hastening fruit maturation when applied in the first half of stage II. The growth retardants Amo 1618 and £CC did not hasten peach fruit maturation.
During this study, we divided the developmental growth pattern of buttercup squash into three phases: 1) early growth, from flowering up to 30 days after flowering; 2) maturation, from 30 days until 60 days after flowering (or harvest); and 3) ripening, from 60 days (or harvest) until ≈100 days after flowering. Harvest occurred at 48 days after flowering. Fruit growth (expansion), starch, and dry matter accumulation were largely completed during early growth, and there was a progressive decline in the respiration rate. Extractable activities of acid and alkaline invertases, sucrose synthase, alkaline α-galactosidase, and sucrose phosphate synthase (assayed with saturating substrates) were high initially but declined markedly during this phase. Glucose, fructose, and low concentrations of raffinose saccharides were present, but no sucrose was detected. During maturation, starch and dry matter remained nearly constant and sucrose began to accumulate. During ripening, starch was degraded, sucrose synthase activity was significant but relatively constant, sucrose phosphate synthase activity increased, and sucrose continued to accumulate.
Potato (Solanum tuberosum L.) periderm forms a barrier at the surface of the tuber that protects it from infection and dehydration. Immature periderm is susceptible to excoriation (skinning injury), which results in costly storage loses and market quality defects. The periderm consists of three different cell types: phellem (skin), phellogen (cork cambium), and phelloderm (parenchyma-like cells). The phellogen serves as a lateral meristem for the periderm and is characterized by thin radial walls that are labile to fracture while the periderm is immature and the phellogen is actively dividing, thus rendering the tuber susceptible to excoriation. As the periderm matures the phellogen becomes inactive, its cell walls thicken and become resistant to fracture, and thus the tuber becomes resistant to excoriation. Little is known about the changes in cell wall polymers that are associated with tuber periderm maturation and the concurrent development of resistance to excoriation. Various changes in pectins (galacturonans and rhamnogalacturonans) and extensin may be involved in this maturational process. The objectives of this research were to compare immunolabeling of homogalacturonan (HG) epitopes to labeling of rhamnogalacturonan I (RG-I) and extensin epitopes to better understand the depositional patterns of these polymers in periderm cell walls and their involvement in tuber periderm maturation. Immunolabeling with the monoclonal antibodies JIM5 and JIM7 (recognizing a broad range of esterified HG) confirmed that HG epitopes are lacking in phellogen walls of immature periderm, but increased greatly upon maturation of the periderm. Labeling of a (1,4)-β-galactan epitope found in RG-I and recognized by the monoclonal antibody LM5 was abundant in phelloderm cell walls, but sparse in most phellem cell walls. LM5 labeling was very sparse in the walls of meristematically active phellogen cells of immature periderm, but increased dramatically upon periderm maturation. Deposition of a (1,5)-α-l-arabinan epitope found in RG-I and recognized by LM6 was abundant in phelloderm and phellogen cell walls, but was sparse in phellem cell walls. LM6 labeling of phellogen walls did not change upon periderm maturation, indicating that different RG-1 epitopes are regulated independently during maturation of the periderm. Labeling with the monoclonal antibody LM1 for an extensin epitope implied that extensin is lacking in phellem cell walls, but is abundant in phelloderm cell walls. Phellogen cell walls did not label with LM1 in immature periderm, but were abundantly labeled with LM1 in mature periderm. These immunolabeling studies identify pectin and extensin depositions as likely biochemical processes involved in the thickening and related strengthening of phellogen walls upon inactivation of the phellogen layer as a lateral meristem and maturation of the periderm in potato tuber. These results provide unique and new insight into the identities of some of the biological processes that may be targeted in the development of new technologies to enhance resistance to tuber skinning injury for improved harvest, handling and storage properties.
-1033.1990.tb19321.x Brummell, D.A. Dal Cin, V. Crisosto, C.H. Labavitch, J.M. 2004 Cell wall metabolism during maturation, ripening and senescence of peach fruit J. Expt. Bot. 55 2029 2039 10.1093/jxb/erh227 Brummell, D.A. Harpster, M.H. 2001 Cell wall
‘Carlos’ muscadine grapes (Vitis rotundifolia Michx.) were sorted into 5 density grades using 4 brine solutions of 8, 9, 10 and 11% NaCl. Soluble solids and berry weight increased, color improved, and acidity decreased with grape maturity and brine concentration. Panelist’s sensory preference increased with increasing density (maturity). Berries that floated and sank in 11% NaCl (density grades 4 and 5) had acceptable ratings for flavor, aroma, and color. Density separation was used to monitor the rates of maturation of the cultivars ‘Carlos’ and ‘Noble’. The technique was useful in characterizing the changes in berry population during the last month of ripening.
Our objectives were to characterize the quality and maturity changes of peach [Prunus persica (L.) Batsch.] fruit cvs. O'Henry and Nos 21 during maturation and ripening and to identify harvest maturity indices by relating nondestructive and destructive variables. After fruit set, 400 fruit of similar diameter and tree position were tagged to follow maturation and ripening on the tree. During commercial harvest, 48 fruit were ramdomly harvested every 4 to 6 days. Ethylene evolution rate (EER) at 20 °C, fresh weight, and peel ground and cover color (L*, a*, b*, C* and Hue value) were measured to all 48 fruit. Flesh color, firmness at several fruit points, soluble solids (SS), pH, titratable acidity (TA), and SS/TA ratio were measured only to 24 fruit, and the rest were held for up to 7 days at 20 °C as a ripening period to measure the same characteristics previously mentioned. Pearson correlation coefficients were determined between variables to explore possible harvest maturity indices. The most significant changes occurred in EER and ground color (a* value) for both varieties and fresh weight only for cv. O'Henry. For `O'Henry' peaches the highest correlation (P < 0.001) was obtained between EER-suture firmness (r = -0.61). For cv. Nos 21 the highest correlation was between EER-shoulder firmness (r = -0.69). It was also found that fruit softening occurred mainly in the fruit shoulder for both cultivars. Therefore, no harvest maturity indices could be established for these cultivars.