Photosynthetic Characteristics of Highbush Blueberry and Rabbiteye Blueberry in Phytotron

Abstract

Photosynthetic characteristics measured with the leaves of 'Weymouth' highbush blueberry (Vaccinium corymbosum L.) and 'Tifblue' rabbiteye blueberry (V. ashei Reade) in phytotron were compared with regard to their responses to light intensity (0-2,000 µmol・m −2 ・s −1 ) and temperature (15-35°C). As temperature increased, photosynthetic rates of both cultivars increased.Photosynthetic rates of 'Weymouth' were higher than those of 'Tifblue' under low temperature conditions (15-20°C). However, there was no difference in photosynthetic rates measured under high temperature conditions (25-35°C), but 'Weymouth' showed higher transpiration rates and lower water use efficiencies (WUE) than 'Tifblue'. Furthermore, photosynthetic characteristics of 'Blueray' highbush blueberry under high temperature conditions (28 and 35°C) were similar to those of 'Weymouth' under high temperature conditions. These findings show that photosynthetic characteristics of leaves could be related to the suitability of highbush blueberries to cool conditions, and to the heat tolerance and drought resistance of rabbiteye blueberries. WUE values measured at high temperature >35°C and high light intensity >1,000 µmol・m −2 ・s −1 could be helpful as indices for evaluating and selecting blueberry plants with heat tolerance. Transpiration rates increased at high temperature and high light intensity, which suggested that shading in summer to control light intensity under 1,000 µmol ・m

A Review for Southern Highbush Blueberry Alternative Production Systems

“…Hence, there is a lack of research on optimizing management practices to maximize SHB yield in greenhouse or plant factory production. Controlling temperature is more feasible in plant factories than in greenhouses [29,30,34,35]. Spann et al [35] compared plant growth under 28 and 21 • C and discovered that flower bud initiation and whole-plant carbohydrate concentration was significantly reduced at 28 • C. Aung et al [30] found that the optimal temperature for SHB cultivars 'Misty' and 'Sharpeblue' should be around 15 • C during dark periods and 25 • C in light periods, which agrees with Kameari et al [34] and Cho et al [29].…”

“…Controlling temperature is more feasible in plant factories than in greenhouses [29,30,34,35]. Spann et al [35] compared plant growth under 28 and 21 • C and discovered that flower bud initiation and whole-plant carbohydrate concentration was significantly reduced at 28 • C. Aung et al [30] found that the optimal temperature for SHB cultivars 'Misty' and 'Sharpeblue' should be around 15 • C during dark periods and 25 • C in light periods, which agrees with Kameari et al [34] and Cho et al [29]. The experiments on SHB cultivars 'Misty' and 'Sharpeblue' showed that relative humidity above 40% can avoid stomatal closure under low humidity and below 80% can reduce disease pressure under high humidity [29,30].…”

Plant Growth and Fruit Quality of Blueberry in a Controlled Room under Artificial Light

“…Furthermore, through research on the responses of plants, the optimal temperature was set at 15°C (dark period) and 25°C (lighting period) in the controlled room. Although the saturated point of Pn was reached under a PPFD value of 800-1000 μmol·m −2 ·s −1 (Kameari et al, 2010), the temperature increased if PPFD was set at 1000 μmol·m at the top of the plants and the photoperiod was set at 10 hours. Low humidity might cause stomatal closure directly by causing water stress in the epidermal tissue and guard cells due to excessive loss of water by a high rate of transpiration (Dai et al, 1992;Loreto and Sharkey, 1990;Rawson and Begg, 1977).…”

“…The study group performed some preliminary tests on various settings of temperature, daylength and photoperiod in order to understand the plant response under different conditions in the controlled room. Kameari et al (2010) suggested that the most suitable temperature for maximum Pn on blueberry plants grown in a phytotron was 25°C. Furthermore, through research on the responses of plants, the optimal temperature was set at 15°C (dark period) and 25°C (lighting period) in the controlled room.…”