Aeroponics is a relatively new soilless culture technology which may produce food in space-limited cities or on non-arable land with high water-use efficiency. The shoot and root growth, root characteristics, and mineral content of two lettuce cultivars were measured in aeroponics, and compared with hydroponics and substrate culture. The results showed that aeroponics remarkably improved root growth with a significantly greater root biomass, root/shoot ratio, and greater total root length, root area, and root volume. However, the greater root growth did not lead to greater shoot growth compared with hydroponics, due to the limited availability of nutrients and water. It was concluded that aeroponics systems may be better for high value true root crop production. Further research is necessary to determine the suitable pressure, droplet size, and misting interval in order to improve the continuous availability of nutrients and water in aeroponics, if it is to be used to grow crops such as lettuce for harvesting above-ground parts.

Aeroponics is a relatively new soilless culture technology, which may produce food in space limited cities or non-arable land with high water use efficiency. The shoot and root growth, root characteristics, mineral contents of two lettuce cultivars were measured in aeroponics, as compared with hydroponics and substrate culture. The results showed that aeroponics remarkably improved the root growth with a significant greater root biomass, root/shoot ratio, and several times higher total root length, root area and root volume. However, the greater root growth did not lead to a better shoot growth compared with hydroponics, due to the limited availability of nutrients and water. It can be concluded that aeroponics systems may be better for high value true root crops production. Further research is necessary to figure out the suitable pressure, droplet size, and misting interval in order to improve the continuously availability of nutrients and water in aeroponics, if it is used to grow crops like lettuce for harvesting above-ground parts.

Aeschynanthus longicaulisplants are understory plants in the forest, adapting to low light conditions in their native habitats. To observe the effects of the high irradiance on growth and physiology, plants were grown under two different light levels, PPFD 650 μmol·m^–2·s^–1and 150 μmol·m^–2·s^–1for 6 months. Plants under high irradiance had significantly thicker leaves with smaller leaf area, length, width, and perimeter compared to the plants grown under low irradiance. Under high irradiance, the leaf color turned yellowish and the total chlorophyll decreased from 5.081 mg·dm⁻²to 3.367 mg·dm⁻². The anthocyanin content of high irradiance leaves was double that of those under low irradiance. The plants under high irradiance had significantly lower A_max(5.69 μmol·m^–2·s^–1) and LSP (367 μmol·m^–2·s^–1) and higher LCP (21.9 μmol·m^–2·s^–1). The chlorophyll fluorescence parameterFv/Fmwas significantly lower and NPQ was significantly higher in high irradiance plants. RLCs showed significantly lowerETRmax⁡andEkin plants under high irradiance. It can be concluded that the maximum PPFD of 650 μmol·m^–2·s^–1led to significant light stress and photoinhibition ofA. longicaulis.

A simple and effective method for quantification of leaf variegation was developed. Using a digital camera or a scanner, the image of a variegated leaf was imported into a computer and saved to a file. Total pixels of the entire leaf area and total pixels of each color within the leaf were determined using an Adobe Photoshop graphics editor. Thus, the percentage of each color's total pixel count in relation to the total pixel count of the entire leaf was obtained. Total leaf area was measured through a leaf area meter; the exact area of this color was calculated in reference to the pixel percentage obtained from Photoshop. Using this method, variegated leaves of ‘Mary Ann’ aglaonema ( Aglaonema x), ‘Ornate’ calathea ( Calathea ornate ), ‘Yellow Petra’ codiaeum ( Codiaeum variegatum ), ‘Florida Beauty’ dracaena ( Dracaena surculosa ), ‘Camille’ dieffenbachia ( Dieffenbachia maculata ), and ‘Triostar’ stromanthe ( Stromanthe sanguinea ) were quantified. After a brief training period, this method was used by five randomly selected individuals to quantify the variegation of the same set of leaves. The results were highly reproducible no matter who performed the quantification. This method, which the authors have chosen to call the quantification of leaf variegation (QLV) method, can be used for monitoring changes in colors and variegation patterns incited by abiotic and biotic stresses as well as quantifying differences in variegation patterns of plants developed in breeding programs.