Today, the stems of edible Opuntia are consumed as vegetables, cattle food, and processed food, in addition to being used for raw materials in cosmetics and medical supplies in various countries, including the Mediterranean, South America, the Middle East, North Africa and Asia, showing their wide adaptability to various climate zones ranging from arid, semiarid to temperate zones. In a time when global warming and population growth requires an urgent response, there is intense demands in crops like edible Opuntia, which are stress-resistant to extreme environments (e.g., high temperature, dryness) and can be grown in large volumes. Thus, Edible Opuntia have promising potential not only to become general crop consumed globally but also to serve as a model plant for deciphering the mechanisms of their special properties. However, their existence and their traits as crop are not well-known at the global level compared with other global crops. This review explains the physiological features, uses and cultivation technologies including soil and hydroponic culture of edible Opuntia with recent researches.
To elucidate effects of climate change on growth and yield of crop plants, we developed a new growth chamber with an air-curtain shed roof. The chamber space was divided into two: one side followed outdoor temperature and the other side was several degrees higher than the outdoor temperature. Furthermore, we tried to assess the real temperature effect by achieving the same vapor pressure deficit (VPD) in two divided spaces and grew rice plants from seedling to maturity stages as an experimental material. For the high temperature (HT) plot, we adopted +4℃ of the outdoor-temperature-following (control; CONT) plot because, in a preliminary experiment, +5℃ of CONT induced sterility in most grains. The HT conditions advanced the day to flowering of rice, but its grain yield was lower than those obtained under CONT conditions. Trial of the same VPD under HT and CONT conditions suggested that the effect of VPD on rice growth and yield was not large during the June―October growth season.
A plant factory with artificial lighting is a closed plant production system designed to produce high yield with good quality. At the high plant densities used in plant factories, outer leaves beneath the dense canopy get insufficient light and senesce fast, resulting in poor yield. Methods that retard the senescence of outer leaves would improve yield and profitability. Here, we examined the effect of supplemental upward lighting with different wavelengths (blue, green, red, and white) and intensities on the retardation of outer leaf senescence, photosynthesis, and plant growth in lettuce (Lactuca sativa L. var romana). Supplemental upward lighting of any type retarded senescence and decreased waste, improving the marketable shoot biomass. Blue and red were most effective, as both are efficiently absorbed by chlorophyll. White, blue, and red, but not green, significantly increased the ascorbic acid content in the outer leaves. These results indicate that supplemental upward lighting with blue, red, or white light-emitting diodes (LEDs) can achieve high yields of lettuce with low waste and a high ascorbic acid content.
Hydroponic Takana (Brassica juncea var. integrifolia) was cultivated with a culture solution adjusted to electrical conductivity (EC) of 0.7 or 1.4 dS m-1, and the culture solution was changed before harvesting. The largest mature leaves of Takana were harvested on day 1, 3, 5, 7 and 10 after changing the culture solution, and the leaf size, fresh weight, nitrate nitrogen content and ascorbic acid content were measured. Using the culture solution adjusted to EC of 0.7 dS m-1 from the beginning of growth showed significantly lower leaf size and fresh weight, and is inappropriate for agricultural production. In addition, the nitrate nitrogen content was rapidly reduced by changing the culture solution to non-fertilizer before harvesting. The increase of ascorbic acid in hydroponic Takana required more than 7 days after nutrient interruption. In conclusion, the yield may decrease on day 10 after changing the culture solution to no fertilizer. Ascorbic acid was negatively correlated with nitrate nitrogen. Moreover, ascorbic acid increased rapidly when nitrate nitrogen was less than 10 mg/100g FW.
To explain the phytohormone profiles of the strawberry fruit, fruits at three stages (green stage, small green; breaker stage, red only at the apex; turning stage, red excluding the apex) were collected, and divided into achenes and receptacles. Indole-3-acetic acid (IAA), abscisic acid (ABA), trans zeatin (Z), isopentenyl adenine (iP), gibberellin1 (GA1), and gibberellin4 (GA4) of the achenes and receptacles are quantified with liquid chromatograph-mass spectrometers. (LC-MS). In the achenes, the IAA concentration was higher at the green stage, but decreased rapidly at the breaker stage. In the achenes, Z concentration was low at the green stage, but increased sharply at the breaker stage. The iP concentration was almost the same in the achene and the receptacle, and increased as the stage progressed. The GA1 concentration was similar in the achenes and receptacles, and was high at the green stage, but decreased rapidly at the breaker stage. The ABA concentration in the achenes and receptacles increased with the stage progressed.