I wanted to excerpt some of their review of the existing literature in the introduction because it really shows how plants respond to different environmental conditions by changing their growth enormously:
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A plant factory system is useful for medicinal plant cultivation because of the managed and optimized environmental conditions such as light intensity, air and root-zone temperature (RZT), humidity, CO2 concentration, and a nutrient solution [5,6,7]. Controlling environmental conditions significantly affected the plant’s synthetic pathways, plant metabolic, and secondary metabolites content [7,8]. Besides air temperature, root-zone temperature (RZT) is an important factor for plant growth and development, nutrient uptake, and accumulation and biosynthesis process of bioactive compounds [9,10]. For example, 10 °C RZT decreased plant growth but increased RA and luteolin concentrations and the contents of red perilla (Perilla frutescens, Labiatae) due to water stress [10]. Optimal RZT for nutrient uptake and plant growth of snapdragons (Antirrhinum majusL. “Peoria”) was 22 °C [11]. Root zone temperature at 26 °C significantly increased shoot growth; however, lower RZT (10 °C) significantly decreased shoot growth and increased soluble sugars in both roots and leaves of cucumber (Cucumis sativus L.) at 10 °C RZT in the hydroponic system after four weeks of RZT treatment [12].
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Mineral nutrient absorption and plant biomass were increased at higher RZT. In addition, the uptake of total N, P, and K of cucumber (Cucumis sativus L.) was decreased at low RZT (10 °C) compared with other treatments [13]. Phenols, anthocyanin, nitrate, antioxidant enzymes, and sugar concentrations at low RZT at 10 °C were increased in leaves of lettuce (Lactuca sativa L.) compared with higher RZT (20, 25, and 30 °C) [9]. Plant growth and water content were decreased at high RZT (33 °C); however, soluble-solid content and total phenolic compounds in carrots (Daucus carota L.) were increased at high RZT treatment compared with other treatments (20, 25, and 29 °C), because high RZT caused drought stress [14]. Plant fresh and dry weights of muskmelons (Cucumis melo L. “Gold Star”) were the highest and the lowest at 25 °C RZT and 35 °C RZT, respectively [15]. Biomass accumulation, antioxidant power, vitamin C, and sugar content of lettuce (Lactuca sativa L.) were affected by root-zone heating [16]. The concentration of N and P and total mineral accumulation K, NO3−, Ca, Fe, Cu, Mn, Mg, and Zn in plants at 20 °C RZT were higher than other treatments [17].
This is another paper I want to dig into soon it’s got some intense charts in the figures section that need studying for me to get them:
