Development of a semi-open chamber system for the gas exchange measurement of whole-canopy under steady and unsteady states in cucumber seedlings.

BACKGROUND: Large-scale data on the photosynthetic characteristics of whole crop canopy is crucial for improving yield. However, current data collection methods remain challenging, and the time constraints associated with photosynthetic data collection further complicate matters. Developing a practical yet easy-to-use tool for collecting whole-canopy data is essential to address these challenges. Furthermore, it is necessary to obtain instantaneous measurements of photosynthetic rate over a wide range of CO2 concentrations under an unsteady state to enable faster data collection and obtain reliable biochemical limits of carbon assimilation. This study developed a semi-open chamber system with steady and unsteady state measurement techniques to collect biochemical photosynthetic data from an entire cucumber canopy, emphasizing the correction procedures for CO2 concentration of unsteady state measurements applicable regardless of chamber scale. RESULTS: After constructing a semi-open chamber system, we described how to correct measurement errors according to chamber volume. In order to assess the accuracy of the newly developed system, an analysis was conducted to determine the overall measurement error resulting from variations in the reference, sample CO2 concentration, and leakage flow rate. The total measurement error was accurate to no more than 10%. Furthermore, the difference between the photosynthetic rate of the single leaf and that of the whole-canopy was not significant in Rubisco activity-limited carboxylation range. In addition, the Farquhar-von Caemmerer-Berry (FvCB) model parameters and the photosynthetic rate estimation values were compared to evaluate the steady- and unsteady state measurement methods between the cucumber seedlings' single-leaf and whole-canopy. The average root mean square error of the FvCB model in the steady (standard A-Ci response) and unsteady states (800 to 400 ramp) of the chambers was 1.4 and 2.3, respectively. Results show that the developed system is suitable for measuring the gas exchange rate of the cucumber canopy. CONCLUSIONS: We demonstrate the correction method for measurement errors to enable the gas exchange rate of the whole-canopy even in an unsteady state. The correction method of the measurement system of the gas exchange rate for the whole- canopy can be applied regardless of the volume of the chamber, and it can be applied simply to other chamber systems. In addition, an unsteady state measurement method for fast data collection was also applicable. However, it was deemed necessary to identify a more optimal measurement range by conducting measurements across a broader range of values.

Estimating the impact of environmental management on strawberry yield using publicly available agricultural data in South Korea.

Advanced information and communication technologies (ICTs) have made data collection more efficient for agricultural studies. Using publicly available database in South Korea, we estimated the relationship between the management of air temperature and relative humidity and the strawberry yield during two harvest seasons. Longitudinal data of multiple greenhouses were merged and processed, and mixed-effects models were applied to account both observed and unobserved factors across the greenhouses. The averages of air temperature and relative humidity inside each greenhouse do not take volatility of the time-varying variables into consideration, so we assessed the management of each greenhouse by the percent of time that air temperature between 15 °C and 20 °C (denoted as T%) and the percent of time that relative humidity between 0% and 50% (denoted by H%). The statistical models estimated that the strawberry yield decreases with respect to the number of days since harvest began and the rate of decrease is slower when T% and H% are higher. This study used large-scale multilocation data to provide the practical suggestion that air temperature and relative humidity should be maintained within the optimal ranges to mitigate the loss of strawberry yield especially at the later phase of a harvest season.

Prediction of strawberry yield based on receptacle detection and Bayesian inference.

The receptacle of strawberry is a more direct part than the flower for predicting yield as they eventually become fruits. Thus, we tried to predict the yield by combining an AI technique for receptacle detection in images and statistical analysis on the relationship between the number of receptacles detected and the strawberry yield over a period of time. Five major cultivars were cultivated to consider the cultivar characteristics and environmental factors for two years were collected to consider the climate difference. Faster R-CNN based object detector was used to estimate the number of receptacles per strawberry plant in given two-dimensional images, which achieved a mAP of 0.6587 for our dataset. However, not all receptacles appear on the two-dimensional images, and Bayesian analysis was used to model the uncertainty associated with the number of receptacles missed by the AI. After estimating the probability of fruiting per receptacle, prediction models for the total strawberry yield at the end of harvest season were evaluated. Even though the detection accuracy was not perfect, the results indicated that counting the receptacles by object detection and estimating the probability of fruiting per receptacle by Bayesian modeling are more useful for predicting the total yield per plant than knowing its cumulative yield during the first month.

Plant Response to Cold Stress: Cold Stress Changes Antioxidant Metabolism in Heading Type Kimchi Cabbage (Brassica rapa L. ssp. Pekinensis).

Cold stress is known as the important yield-limiting factor of heading type Kimchi cabbage (HtKc, Brassica rapa L. ssp. pekinensis), which is an economically important crop worldwide. However, the biochemical and molecular responses to cold stress in HtKc are largely unknown. In this study, we conducted transcriptome analyses on HtKc grown under normal versus cold conditions to investigate the molecular mechanism underlying HtKc responses to cold stress. A total of 2131 genes (936 up-regulated and 1195 down-regulated) were identified as differentially expressed genes and were significantly annotated in the category of "response to stimulus". In addition, cold stress caused the accumulation of polyphenolic compounds, including p-coumaric, ferulic, and sinapic acids, in HtKc by inducing the phenylpropanoid pathway. The results of the chemical-based antioxidant assay indicated that the cold-induced polyphenolic compounds improved the free-radical scavenging activity and antioxidant capacity, suggesting that the phenylpropanoid pathway induced by cold stress contributes to resistance to cold-induced reactive oxygen species in HtKc. Taken together, our results will serve as an important base to improve the cold tolerance in plants via enhancing the antioxidant machinery.

Effects of exercise training on health capabilities and life satisfaction among overweight and obese African American women.

More importance has been placed on exercise training due to increase in the overweight and obese population. However, few studies have researched the effects of exercise training on the health capabilities and life satisfaction levels of overweight and obese African American women. This study sought to determine the effect of a 12-week exercise training on health capabilities and life satisfaction levels of overweight and obese African American women. Participants, who passed an initial screening and pre-assessment, were measured current health capabilities and life satisfaction levels both prior to, and following, the 12-week exercise training. The results from this study indicated an improvement in health capabilities, although with no significant differences following exercise training, while a significantly higher life satisfaction levels was observed among the overweight and obese African American women. The findings suggest that exercise training can be beneficial to enhance overweight and obese African American women's health capabilities and life satisfaction levels. Exercise professionals should provide the appropriate exercise trainings so that overweight and obese African American women can optimize life satisfaction levels.

Influence of drought stress on bioactive compounds, antioxidant enzymes and glucosinolate contents of Chinese cabbage (Brassica rapa).

This study investigated the effects of drought stress on Chinese cabbage (Chcab) by measuring plant growth responses, total antioxidant enzyme activities, the contents of bioactive compounds including glucosinolates (GLS, aliphatic and indolic), and binding with human serum albumin (HSA). Forty-day-old Chinese cabbage (Brassica rapa L. ssp. pekinensis) seedlings were transplanted into pots and maintained for three weeks at 10% (drought-treated, D-T) and 30% (control, C) soil water. The total leaf number, leaf area, and fresh and dry weights were significantly lower in D-T Chcab than in controls. Total GLSs and catalase activities were found to be significantly higher in D-T Chcab than in controls. Indolic GLSs were significantly higher than aliphatic GLSs in D-T Chcab. These results show that D-T Chcab reduced growth parameters and binding properties with HSA and influenced total contents of GLSs, polyphenols, flavonoids, total antioxidant enzyme activities, catalase and peroxidase.

Impact of moderate and extreme climate change scenarios on growth, morphological features, photosynthesis, and fruit production of hot pepper.

Horticultural crop production and changes in physiological aspects during the growing season may be affected by climate change factors (CC), which include increased temperature and the associated doubling or tripling of atmospheric CO2 concentrations. However, the potential effects are complex and many parameters might impact on the observed effects. To evaluate the effects of CC, the growth, yield, fruit characteristics, photosynthetic traits, and morphological characteristics of hot peppers were investigated. The hot peppers were grown under two CC scenarios, with the Representative Concentration Pathway (RCP) of 4.5 (Temp.; +3.4°C, CO2 conc.; 540 µmol/mol, Precipitation +17.3%) and RCP 8.5 (Temp.; +6.0°C and CO2 conc.; 940 µmol/mol, Precipitation +20.3%), respectively, using extreme weather simulators. This was compared with existing weather conditions occurring in Jeonju, South Korea in terms of air temperature, relative humidity, radiation, and precipitation. Overall, the plant height showed the highest under moderate CC conditions (RCP 4.5) among all the treatments tested. The number of leaves in the RCP 8.5 condition showed 7,739/plants, which was 2.2 times higher than that of the control. In addition, fruit shape was shortened and percentage dry matter was also the highest. The yield of hot pepper in the CC RCP 4.5 and 8.5 conditions were decreased by 21.5% and 89.2% when compared with that of the control, respectively. The days to harvest in the condition of CC scenarios were shortened from 5 to 13 compared with that of control, predominantly due to the increased air temperature. The results indicated that the severe RCP CC scenarios made reduction in the yields and negative affection on the fruit qualities. Overall, hot pepper was tolerant of mild CC scenarios of temperature × CO2 but was significantly affected by more extreme CC interacting parameter concentrations (or similar).

Comparison of passive and active leisure activities and life satisfaction with aging.

AIM: Many older adults face limitations to participating in active leisure activities as a result of their physical constraints from aging. Passive leisure activities become alternative leisure activities for older adults as a result of limited physical capacity. The present study sought to determine whether there exists a difference in the frequency of participation in passive and active leisure activities, and the effect of participation in passive and active leisure activities on the life satisfaction level of old adults. METHODS: A total of 460 participants aged 60-95 years were randomly selected from 21 sites in the USA. The Life Satisfaction Index - Z and the Meaningful Activity Participation Assessment were analyzed to examine older adults' life satisfaction and frequency of active or passive activities. RESULTS: The results showed that participation in passive leisure activities, such reading, talking on the telephone and watching TV/listening to the radio, is more frequent among older adults (P = 0.000). The regression coefficient found that club/organization or volunteering (P = 0.008), homemaking/maintenance (P = 0.017) and traveling (P = 0.017) for active leisure activities were statistically significant predictors of Life Satisfaction Index - Z for older adults. CONCLUSIONS: The current study shows that older adults spent much more times participating in passive leisure activities, such as radio/watching TV, talking on the phone and reading. The result also showed that active leisure activities, such as club/organization or volunteering, home making/maintenance and traveling, were significant predictors of life satisfaction for older adults controlling for covariates. The current study suggests marketing and programming plans to overcome the constraints that influence older adults' life satisfaction. Geriatr Gerontol Int 2018; 18: 380-386.

Variation of bioactive compounds content of 14 oriental strawberry cultivars.

Variation in bioactive compounds content was assessed in antioxidant rich June-bearing strawberry cultivars. Ascorbic acid, anthocyanin, and ellagic acid content were analyzed in ripe fruits of 14 cultivars. The bioactive content in strawberry fruit was found to vary significantly among cultivars and from year to year. The highest ascorbic acid content was found in 'Sugyeong'. The 'Red Pearl' and 'Sachinoka' had three to fourfold higher amounts of pelargonidin 3-glucoside than other cultivars. For cyanidin 3-glucoide and pelargonidin 3-rutinoside, two other characterized anthocyanins, 'Dahong' and 'Keumhyang' had the highest contents among all the tested cultivars. The ellagic acid content of 'Dahong' was generally all within the upper ranges. These results can be used for the validation of fruit antioxidant capacity and in addition, provide useful information for breeding programs looking to enhance the antioxidant capacity in strawberry fruit.