A method has been developed for rapid and non invasive determination of chlorophyll content of leaves of micropropagated potato plants using RGB based image analysis. Among the trichomatic colors, R and G negatively correlated with the chlorophyll content, while a positive correlation was observed with B chromate. Compared to mean brightness value, the use of mean brightness ratio considerably improved the relationship of the tricolors with chlorophyll content. The brightness values and ratios of the primary colors are modeled as linear correlation functions for chlorophyll content. A significant correlation was observed between the model predicted chlorophyll content with the chlorophyll content measured by chlorophyll content meter. Spectral properties such as luminosity and saturation were also found to be negatively correlated with the chlorophyll content. The relationship was improved by combining the mean brightness ratio at B band region with luminosity. The potential of the imaging system in micropropagation has been discussed.

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Grey mould (Botrytis cinerea) is a very successful necrotroph, causing serious losses in more than 200 crop hosts. This study investigated the antifungal effect of 405-nm light on this pathogen. Our results suggest that the excitation of endogenous porphyrins and subsequent accumulation of singlet oxygen contribute to the 405-nm light-mediated photoinactivation of grey mould. The development of symptoms in detached tomato leaves inoculated with B. cinerea spores was significantly inhibited by irradiation with 405-nm light, indicating that this wavelength of light has a potential use in controlling plant diseases caused by B. cinerea.

Drought, the result of regional climatic variability is one of the dominant threats to environment. This study focuses on the biophysical, environmental and health issues concerning drought occurrence in northwest region of Bangladesh. Using both primary and secondary data, the analysis revealed that, during the drought period, rainfall as the dominant factor of supplying surface water and normalizing the dryness of the nature was almost 46% lower than the previous (normal) years. Similarly, average monthly sunshine hours in the drought year was about 7% higher compared to that of the normal year. On an average, groundwater level declined more than one meter compared to the previous years. Thus, many of the tubewells turned dry or failed to supply the required quantity of water for household and irrigation purposes. A significant number of surface water bodies including ponds, ditches, canals and streams had little volume of low quality water. In normal years, almost all households used hand tubewells (HTWs) as the major source of drinking water, while in the drought period only 90% households could use HTW water since substantial proportion of the HTWs turned dry. People had to collect drinking and domestic water from far distance to meet the basic requirements. Increase in temperature and prevalence of severe dust during drought periods compared to the normal years caused different health hazards including dysentery and diarrhoea due to unsafe drinking water.

An increasing population and limited arable land area endanger sufficient and variegated food supplies worldwide. Greenhouse cultivation enables highly intensive plant production and thereby enables the production of abundant fresh vegetables and fruits. The salient benefits of greenhouse cultivation are supported by ingenious management of crop environments, assisted by fossil fuel and grid electricity supplies. To reduce dependence on traditional energy resources, various studies have investigated exploitation of renewable energies for greenhouse environment management. Among them, solar photovoltaic (PV) technologies are anticipated to feed electrical energy to greenhouse appliances for microclimate control. This study proposes a venetian-blind-type shading system consisting of semi-transparent PV modules as blind blades based on micro-spherical solar cell technology to achieve greenhouse shading and electricity production concurrently. In response to the solar irradiance level, the PV blind inclination was altered automatically using a direct current (DC) motor driven by electrical energy generated by the PV blind itself. The PV blind was operated continuously during a five-month test period without outage. Moreover, the PV blind generated surplus electrical energy of 2125 kJ for blind system operations during the test period. The annual surplus energy calculated under the present experimental condition was 7.8 kWh m −2 year −1 , suggesting that application of the PV blind to a greenhouse roof enables sunlight level control and electrical appliance operations in the greenhouse with a diminished fuel and grid electricity supply, particularly in high-insolation regions.Energies 2018, 11, 1681 2 of 23 produces carbon dioxide emissions, the amounts of which should be reduced in the agricultural sector [2]. Under these circumstances, various studies have been conducted to use renewable energy for managing greenhouse crop environments [3,4]. Among them, solar photovoltaics (PVs) are expected to feed electricity to appliances that are used for greenhouse environment management [5].Deploying PV arrays on the sunny ground beside a greenhouse is the simplest and most effective mode of electrical energy generation. For instance, fan and pad cooling systems in Saudi Arabia [6] and in Arizona [7], a fog cooling system in Malaysia [8], and heat pump systems in Italy [9,10] were operated with power from ground-mounted PV arrays. Nevertheless, installing PV arrays partially on a greenhouse roof might be preferred if the PV panels are intended as shading materials. Shading is a fundamentally important practice for greenhouse cultivation in high-insolation regions, such as Spain [11] or Saudi Arabia [12]. Previous studies conducted in Japan [13] and in the Mediterranean region [14,15] demonstrated that an adequate level of shading mitigates excessive temperature rises in greenhouses in summer, improving crop growth and quality [16,17]. Conventionally, nets [14,15,18] and reflective coatings [18,19] have been used as practical ...