Michiko Takagaki

Physiological and psychological effects of walking on young males in urban parks in winter

BackgroundInteraction with nature has a relaxing effect on humans. Increasing attention has been focused on the therapeutic effects of urban green space; however, there is a lack of evidence-based field research. This study provided scientific evidence supporting the physiological and psychological effects of walking on young males in urban parks in winter.FindingsSubjects (13 males aged 22.5 ± 3.1 years) were instructed to walk predetermined 15-minute courses in an urban park (test) and in the city area (control). Heart rate and heart rate variability (HRV) were measured to assess physiological responses. The semantic differential (SD) method, Profile of Mood States (POMS), and State-Trait Anxiety Inventory (STAI) were used to determine psychological responses.Heart rate was significantly lower and the natural logarithm of the high frequency component of HRV was significantly higher when walking through the urban park than through the city area. The results of three questionnaires indicated that walking in the urban park improved mood and decreased negative feelings and anxiety.ConclusionsPhysiological and psychological data from this field experiment provide important scientific evidence regarding the health benefits of walking in an urban park. The results support the premise that walking in an urban park has relaxing effects even in winter.

Physiological and Psychological Effects of a Walk in Urban Parks in Fall.

In recent times, attention has been focused on the role of urban green spaces in promoting human health and well-being. However, there is a lack of evidence-based research on the physiological effects of walking in urban green areas. This study aimed to clarify the physiological and psychological effects of walking in urban parks during fall. Twenty-three males (mean age 22.3 ± 1.2 years) were instructed to walk predetermined 15-min courses in an urban park and in a nearby city area (control). Heart rate and heart rate variability were measured to assess physiological responses, and the semantic differential method, Profile of Mood States, and State-Trait Anxiety Inventory were used to measure psychological responses. We observed that walking in an urban park resulted in a significantly lower heart rate, higher parasympathetic nerve activity, and lower sympathetic nerve activity than walking through the city area. In subjective evaluations, participants were more “comfortable,” “natural,” “relaxed,” and “vigorous” after a walk in the urban park. Furthermore, they exhibited significantly lower levels of negative emotions and anxiety. These findings provide scientific evidence for the physiological and psychological relaxation effects of walking in urban parks during fall.

Nighttime Supplemental LED Inter-lighting Improves Growth and Yield of Single-Truss Tomatoes by Enhancing Photosynthesis in Both Winter and Summer

Greenhouses with sophisticated environmental control systems, or so-called plant factories with solar light, enable growers to achieve high yields of produce with desirable qualities. In a greenhouse crop with high planting density, low photosynthetic photon flux density (PPFD) at the lower leaves tends to limit plant growth, especially in the winter when the solar altitude and PPFD at the canopy are low and day length is shorter than in summer. Therefore, providing supplemental lighting to the lower canopy can increase year-round productivity. However, supplemental lighting can be expensive. In some places, the cost of electricity is lower at night, but the effect of using supplemental light at night has not yet been examined. In this study, we examined the effects of supplemental LED inter-lighting (LED inter-lighting hereafter) during the daytime or nighttime on photosynthesis, growth, and yield of single-truss tomato plants both in winter and summer. We used LED inter-lighting modules with combined red and blue light to illuminate lower leaves right after the first anthesis. The PPFD of this light was 165 μmol m-2 s-1 measured at 10 cm from the LED module. LED inter-lighting was provided from 4:00 am to 4:00 pm for the daytime treatments and from 10:00 pm to 10:00 am for the nighttime treatments. Plants exposed only to solar light were used as controls. Daytime LED inter-lighting increased the photosynthetic capacity of middle and lower canopy leaves, which significantly increased yield by 27% in winter; however, photosynthetic capacity and yield were not significantly increased during summer. Nighttime LED inter-lighting increased photosynthetic capacity in both winter and summer, and yield increased by 24% in winter and 12% in summer. In addition, nighttime LED inter-lighting in winter significantly increased the total soluble solids and ascorbic acid content of the tomato fruits, by 20 and 25%, respectively. Use of nighttime LED inter-lighting was also more cost-effective than daytime inter-lighting. Thus, nighttime LED inter-lighting can effectively improve tomato plant growth and yield with lower energy cost compared with daytime both in summer and winter.

Growth and Accumulation of Secondary Metabolites in Perilla as Affected by Photosynthetic Photon Flux Density and Electrical Conductivity of the Nutrient Solution

The global demand for medicinal plants is increasing. The quality of plants grown outdoors, however, is difficult to control. Myriad environmental factors influence plant growth and directly impact biosynthetic pathways, thus affecting the secondary metabolism of bioactive compounds. Plant factories use artificial lighting to increase the quality of medicinal plants and stabilize production. Photosynthetic photon flux density (PPFD) and electrical conductivity (EC) of nutrient solutions are two important factors that substantially influence perilla (Perilla frutescens, Labiatae) plant growth and quality. To identify suitable levels of PPFD and EC for perilla plants grown in a plant factory, the growth, photosynthesis, and accumulation of secondary metabolites in red and green perilla plants were measured at PPFD values of 100, 200, and 300 μmol m-2 s-1 in nutrient solutions with EC values of 1.0, 2.0, and 3.0 dS m-1. The results showed significant interactive effects between PPFD and EC for both the fresh and dry weights of green perilla, but not for red perilla. The fresh and dry weights of shoots and leafy areas were affected more by EC than by PPFD in green perilla, whereas they were affected more by PPFD than by EC in red perilla. Leaf net photosynthetic rates were increased as PPFD increased in both perilla varieties, regardless of EC. The perillaldehyde concentration (mg g-1) in red perilla was unaffected by the treatments, but accumulation in plants (mg per plant) was significantly enhanced as the weight of dry leaves increased. Perillaldehyde concentrations in green perilla showed significant differences between combinations of the highest PPFD with the highest EC and the lowest PPFD with the lowest EC. Rosmarinic acid concentration (mg g-1) was increased in a combination of low EC and high PPFD conditions. Optimal cultivation conditions of red and green perilla in plant factory will be discussed in terms of plant growth and contents of medicinal ingredients.

Yield and Growth of Sweetpotato Using Plug Transplants as Affected by Their Ages and Planting Depths

The yield and growth of sweetpotato using plug transplants with roots and 3–6 unfolded leaves were compared with those of sweetpotato using conventional cuttings without roots and with 7–8 unfolded leaves (Control). The plug transplants were produced under artificial light using single node cuttings each with one unfolded leaf. The plug transplants of 11- and 15-day old were planted with 1 and 3 nodes inside the soil ridges (called 1- and 3-node depth, respectively, hereafter) to find out the optimum age of transplants and optimum depth of planting for higher yield of sweetpotato. The yield of storage roots 115 days after planting in the field was 40 ton ha-1 when using 15-day old transplants planted with 3-node depth and was 17 ton ha-1 greater than that in the Control. The number of storage roots per plant was 4.7 when using 11-day old transplants planted with 3-node depth and was 1.6 greater than that in the Control. The percent harvest index on day 115 was 81% when using 15-day old transplants planted with 3-node depth. The overall performance of the plug transplants was significantly higher than that of the conventional cuttings. The plug transplants planted with 3-node depth showed higher overall performance than did the plug transplants planted with 1-node depth.

Micro- and Mini-PFALs for Improving the Quality of Life in Urban Areas

Some residents living in urban areas with little chance to grow plants outdoors have recently started enjoying indoor farming using a household plant factory with artificial light (PFAL) or micro-PFAL in Japan, Taiwan, and China and a few other Asian countries. In addition, mini-PFALs have been set up for various purposes at restaurants, cafes, shopping centers, schools, community centers, hospitals, etc. Such micro- and mini-PFALs and their networks could help bring new lifestyles related to local production for local consumption, food, health, ecology, the environment and the Internet to people living in urban areas. This chapter describes the characteristics, functions, and examples of micro- and mini-PFALs.

A Quantitative Analysis of Nutrient Requirements for Hydroponic Spinach (Spinacia oleracea L.) Production Under Artificial Light in a Plant Factory

Surplus absorption of elements that contribute little to crop productivity and quality can be avoided, and fertilizer consumption costs minimized, by applying elements quantitatively to the nutrient solution fed to the plants. The aim of this study was to determine the minimum macronutrient requirements of spinach (Spinacia oleracea L.) with a desired plant size, so that fertilizer management in plant factories can be maximized. Spinach plants were grown in a plant factory (20°C/17°C day/night temperature, photosynthetic photon flux (PPF) of 350 μmol·m-2·s-1 for 12 hours per day using cool-white fluorescent lamps, 1,000 μmol·mol-1 CO2). Spinach grew and developed rapidly, and reached its desired marketable size in only 12–15 days after being transplanted to the study conditions. At day 15 of cultivation under the treatment conditions, the required quantities of macronutrients per plant (90 grams in fresh weight) were determined as follows: 191 mg N, 31 mg P, 345 mg K, 34 mg Ca, 38 mg Mg, and 13 mg S. In conclusion, a quantitative nutrient managing method with low nutrient concentrations is feasible and resource-saving for hydroponic vegetable production in plant factories.

Lettuce production using a commercial scale recirculated capillary hydroponic system

Three experiments were carried out sequentially in spring, summer and fall to study the possibility of producing butterhead lettuce (Lactuca sativa L.) using a capillary hydroponic system (CHS) on a commercial scale under tropical environmental conditions. In all the experiments, two temperature regimes combined with two flow rates of nutrient solution were applied. The air temperature was controlled in the ranges of 25-30•Ž and 30-35•Ž and the solution flow rates were 50 or 80 ml•Emin-1•Em-1. For all the three growing seasons, better plant growth was associated with the lower temperature regime. Higher water flow rate stimulated plant growth only in the summer growing period under the higher temperature regime, due to the larger amount of dissolved oxygen in the nutrient solution. Although the plant quality parameters and leaf color remained unaffected under most of the temperature regimes and flow rates, they differed according to the seasons. In general, higher SPAD values and nitrate concentrations were observed in the spring and fall growing seasons as well. Lower SPAD values and higher vitamin C concentrations were recorded in the summer growing season. The estimated cost of the required-materials for constructing a 1000m2 CHS in Paraguay and Thailand amounted to \665,950 and \659,100 respectively, based on the price of the materials in each country. Estimated cost of the materials in Japan was threefold higher than that in the tropical countries. All the year round lettuce production under tropical conditions using CHS was considered to be fairly possible, since the microclimatic conditions in the greenhouses were similar to those of outdoor tropical conditions.

Effective Storage Conditions for Subsequent Growth Enhancement of Ficus Carica L. Cuttings

For fig plants propagation in Japan, cultural environments require harvested branches as primary cuttings to be stored from February until late March or early April to avoid low temperature and moisture in the ground. Although it has been known that environmental conditions during the storage period of cuttings affect subsequent growth of seedlings after planting secondary cuttings to the field, the relationship between the storage conditions and the growth is still unclear. Thus in the present study, the effects of different storage conditions and planting date of hardwood cutting on the growth of fig (Ficus carica L. cv. Masui Dauphin) seedlings were investigated. Storage conditions were controlled in the environmentally controlled chamber. The results indicated that longer the storage period in the chamber increased shoot dry weight and number, length and dry weight of root. The cuttings moved from field condition to environmentally controlled chamber within two weeks after the harvest had the highest values in the number of root, root dry weight and shoot length in both planting dates.