"SSC had a variable response, with no difference detected in some instances (at P ≤ 0.05) even when all other indicators showed significant differences in maturity indices between treatment groups (Table 5). Overall, our results are in contrast with those obtained by Tromp (1997) as fruit in our study continued to expand until harvest and we determined an opposite response of soluble solids concentration to temperature. Early termination of fruit growth coupled with a more restricted root growth volume, low fruit numbers per tree, and a lower PPF in the controlled temperature treatments, may have had an impact on the carbohydrate balance in the fruit used in Tromp's (1997) study and could account for these differences. "
[Show abstract][Hide abstract] ABSTRACT: Container-grown 'Delicious', 'Golden Delicious', 'Braeburn', 'Fuji' and 'Royal Gala' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] trees, on Mailing 9 (M.9) rootstock, were subjected to a range of different maximum/minimum air temperature regimes for up to 80 days after full bloom (DAFB) in controlled environments to investigate the efforts of temperature on fruit expansion, final fruit weight, and fruit maturation. Fruit expansion rates were highly responsive to temperature with those at a mean of 20 °C being ≃10 times greater than those at a mean of 6 °C. All cultivars exhibited the same general response although 'Braeburn' consistently showed higher expansion rates at all temperatures compared with lowest rates for 'Golden Delicious' and intermediate rates for both 'Delicious' and 'Fuji'. The duration of cell division, assessed indirectly by measuring expansion rate, appeared to be inversely related to mean temperature (i.e., prolonged under cooler conditions). Subsequently, fruit on trees from the coolest controlled temperature treatment showed greater expansion rates when transferred to the field arid smaller differences in fruit size at harvest than would have been expected from the measured expansion rates under the cool treatment. Nonetheless, mean fruit weight from warm postbloom treatments was up to four times greater at harvest maturity than that from cool temperature treatments. Postbloom temperature also markedly affected fruit maturation. Fruit from warm postbloom temperature conditions had a higher soluble solids concentration, more yellow background color, lower flesh firmness, and greater starch hydrolysis than fruit from cooler temperatures.
Journal of the American Society for Horticultural Science. American Society for Horticultural Science 09/1999; 124(5):468. · 1.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Plant phenology is strongly controlled by climate and has consequently become one of the most reliable bioindicators of ongoing climate change. We used a dataset of more than 200 000 records for six phenological events of 29 perennial plant species monitored from 1943 to 2003 for a comprehensive assessment of plant phenological responses to climate change in the Mediterranean region. Temperature, precipitation and North Atlantic Oscillation (NAO) were studied together during a complete annual cycle before phenological events to determine their relative importance and potential seasonal carry-over effects. Warm and dry springs under a positive phase of NAO advance flowering, leaf unfolding and fruiting dates and lengthen the growing season. Spatial variability of dates (range among sites) was also reduced during warm and dry years, especially for spring events. Climate during previous weeks to phenophases occurrence had the greatest impact on plants, although all events were also affected by climate conditions several months before. Immediate along with delayed climate effects suggest dual triggers in plant phenology. Climatic models accounted for more than 80% of variability in flowering and leaf unfolding dates, and in length of the growing season, but for lower proportions in fruiting and leaf falling. Most part of year-to-year changes in dates was accounted for temperature, while precipitation and NAO accounted for <10% of dates' variability. In the case of flowering, insect-pollinated species were better modelled by climate than wind-pollinated species. Differences in temporal responses of plant phenology to recent climate change are due to differences in the sensitivity to climate among events and species. Spring events are changing more than autumn events as they are more sensitive to climate and are also undergoing the greatest alterations of climate relative to other seasons. In conclusion, climate change has shifted plant phenology in the Mediterranean region.
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