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

Abstract

The purpose of this study was to clarify the plant growth and fruit quality of blueberry in a controlled room under artificial light. Cultivars used were a northern highbush 'Blueray', and two southern highbush, 'Misty' and 'Sharpblue'. A comparative study was carried out of growth characteristics, photosynthetic potential and fruit quality analysis in different growing environments, in particular focusing on plants growing in a glasshouse under natural sunlight and plants in a controlled room under artificial light. Environmental conditions of the controlled room under artificial light were 15 to 25°C, 50 to 70% humidity, 150 to 350 μmol·m −2 ·s −1 light intensity, and a 10-hour photoperiod from the primary experiment. In these growing environments, normal fruits developed from all the tested cultivars by successful growth without decreasing plant vigor and leaf photosynthetic ability until fruit harvesting time compared to the cultivars grown in the glasshouse under natural sunlight condition. Moreover, it was confirmed that high-quality fruits could be harvested in a controlled environment to increase fruit production with high SSC % and high anthocyanin content but low acid % in 'Blueray' and 'Misty', but not 'Sharpblue'. Finally, this report presents the possibility of high-quality blueberry production in a controlled environment under artificial light conditions with some cultivars.

A Review for Southern Highbush Blueberry Alternative Production Systems

“…Artificial lighting can be used to supplement sunlight in order to extend the photoperiod in the greenhouse or as an exclusive light source for a plant factory. Different cultivars had varying reactions to natural sunlight and artificial light, but photosynthetic rates under artificial light were found to be more constant [30]. Although photosynthetic rates increase with light intensity from 0 to 1000 µmol.m −2 .s −1 , temperature also increases with light intensity, and thus, more energy is consumed [30].…”

“…In the current literature, most SHB research in greenhouse or plant factory conditions is focused on investigating plant growth, photosynthetic ability, and fruit quality by adjusting the photoperiod, temperature, humidity, and other environmental factors [29][30][31][32]. Studies exploring the potential yield in greenhouse production is limited to a study conducted by Motomura et al [33] in Volcano, Hawaii.…”

“…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].…”

Effect of organic acids on the alteration of black rice anthocyanins by Enterobacter aerogenes NBRC 13534

“…However, since anthocyanins are natural plant pigments, a multi-step process, including crop production, extraction, filtration, and purification, is necessary (Adachi and Yoshitama, 2004). Yields are also dependent on factors such as weather during crop cultivation (Aung et al, 2014). Therefore, in vitro approaches to the production of anthocyanins, where weather is not a factor, are being studied.…”