Nutrient Solution Temperature Affects Growth and °Brix Parameters of Seventeen Lettuce Cultivars Grown in an NFT Hydroponic System

Abstract

Nutrient solution temperature in a hydroponic system affects °Brix and yield of lettuce; thus, it is important to maintain the water temperature within an appropriate range. Nutrient-film technique (NFT) trials were conducted to investigate the effects of different water temperatures (18.3 °C, 21.1 °C, and ambient) on growth and °Brix of 17 cultivars from five different types (Loose leaf, Romaine, Butterhead, Salanova, and Batavian) of lettuce. The average daily water temperature for ambient treatment was recorded to be 20 to 26.5 °C. The study was conducted in a split-plot design with three replications over time. Results indicated that water temperature affected root and shoot fresh and dry weight, plant width, and °Brix for lettuce. Lettuce grown at 21.1 °C were 15% greater for shoot fresh weight than plants grown at ambient conditions. All the growth and quality parameters of lettuce were found to be affected by cultivars, with “Coastal Star” showing the best results in both growth and °Brix parameters. All the cultivars of the Romaine type showed greater growth and °Brix, while Salanova lettuce did not perform well in all treatments compared to other lettuce types. For CO2 assimilation, the interaction between water temperature and cultivars was significant, with “Parris Island” having the greatest rate at ambient water temperature. These results suggested that maintaining water temperature at 21.1 °C produced lettuce with greater growth and biomass but had 26% lower °Brix than lettuce grown at 18.3 °C.

Effects of Hydrogen Peroxide Products on Basil, Lettuce, and Algae in an Ebb and Flow Hydroponic System

“…Hydrogen peroxide products often combine hydrogen peroxide with peracetic acid to provide stability and high reactivity on both inorganic and organic compounds [41]. Rates and timing of application have been found to be largely dependent on crop, algal species and density, water chemistry and environment, and specific system [19,42,43]. Rates as low as 12.3 mg L −1 hydrogen peroxide combined with 8 mg L −1 peracetic acid to control algae to 185 mg L −1 hydrogen peroxide plus 120 mg L −1 peracetic acid with 1 min contact time are recommended to control some pathogens [38].…”

“…As environmental runoff is a concern, hydrogen peroxide degrades rapidly into two byproducts: oxygen and water [16,17]. Both byproducts are relatively harmless in the environment and may even increase the DO content in the remaining water [18,19]. Internally in the plant, hydrogen peroxide exists as a signaling molecule for abiotic stresses and is thought to protect organelle membranes and increase the stress resistance [20][21][22].…”

Ảnh hưởng của công thức dung dịch dinh dưỡng đến sinh trưởng và năng suất dưa hấu (Citrullus lanatus) trồng bằng kỹ thuật thủy canh ngâm rễ

“…Ở điều kiện nhiệt độ cao kéo dài, vùng rễ bị thiếu oxy có thể dẫn đến năng suất cây trồng kém và tăng tỷ lệ bệnh (Chun & Takakura, 1994). Theo Thakulla et al (2021), nhiệt độ dung dịch dinh dưỡng thủy canh có ảnh hưởng đến rễ, khối lượng tươi, khối lượng khô và độ Brix trên cây trồng. Để rễ và chồi phát triển tối đa, tốc độ phát triển chồi và hút nước cao nhất, nhiệt độ rễ tối ưu là khoảng 25°C (Tindall et al, 1990)…”

Effects of Foliar Amino Acid and Vitamin Applications on Heat Stress, Production, and Quality of Lettuce Head Improvements

“…Specifically, it is also called controlled environment agriculture because raising plants hydroponically requires controlling environmental factors (e.g., water temperature, light intensity and duration, humidity, pH of the solution, and mineral nutrients). Hydroponics offers advantages compared to soilbased systems because of the more efficient use of fertilizers and water, more control of the growing climate, and better pest control (Thakulla et al 2021). However, the efficiency of this plant-growing method has not been examined in some crops.…”