High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing...High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing.One of the important ways to improve the quality of cucumber seedlings is to improve the light environment by using artificial light source.In this study,three cucumber seedlings(cv.Jintong,cv.Yunv and cv.Xiazhiguang)were grown for 23 d under eight levels of daily light integral(DLI)at 4.3 mol/(m^(2)·d),8.6 mol/(m^(2)·d),10.1 mol/(m^(2)·d),13.0 mol/(m^(2)·d),5.8 mol/(m^(2)·d),11.5 mol/(m^(2)·d),14.4 mol/(m^(2)·d)and 17.3 mol/(m^(2)·d),respectively.The results showed that when DLI was 14.4 mol/(m^(2)·d),the seedling height,stem diameter,total leaf area and shoot dry/fresh weight of all three cucumber cultivars reached the maximum,while hypocotyl length decreased with the increase of light intensity.When DLI was 14.4 mol/(m^(2)·d),Jintong and Xiazhiguang had the highest health index,which were 49.29 and 28.56,respectively,while that of Yunv was 81.59(DLI=14.4 mol/(m^(2)·d)).With the increase of DLI,the photosynthetic capacity of cucumber increases gradually.The highest net photosynthetic rate was shown at DLI of 14.4 mol/(m^(2)·d),while the chlorophyll content of cucumber seedlings of all three cultivars were less affected by DLI.Jintong and Yunv had the highest chlorophyll content when DLI was 8.6 mol/(m^(2)·d)because they were adapted to low-light environment.In conclusion,the DLI of 14.4 mol/(m^(2)·d)for Jintong and Xiazhiguang,while that of 17.3 mol/(m^(2)·d)for Yunv are suggested for the light environment design of factory-cultivated seedling for cucumber.展开更多
Hydroponic farming is a viable and economical farming method,which can produce safe and healthy greens and vegetables conveniently and at a relatively low cost.It is essential to provide supplemental lighting for crop...Hydroponic farming is a viable and economical farming method,which can produce safe and healthy greens and vegetables conveniently and at a relatively low cost.It is essential to provide supplemental lighting for crops grown in greenhouses to meet the daily light requirement,Daily Light Integral(DLI).The present paper investigates how effectively and efficiently LEDs can be used as a light source in hydroponics.It is important for a hydroponic grower to assess the requirement of photo synthetically active radiation(PAR)or the Photosynthetic Photon Flux Density(PPFD),in a greenhouse,and adjust the quality and quantity of supplemental lighting accordingly.A Quantum sensor(or PAR sensor)can measure PAR more accurately than a digital light meter,which measures the light intensity or illuminance in the SI unit Lux,but a PAR sensor is relatively expensive and normally not affordable by an ordinary farmer.Therefore,based on the present investigation and experimental results,a very simple way to convert light intensity measured with a Lux meter into PAR is proposed,using a simple conversion factor(41.75 according to the present work).This allows a small-scale hydroponic farmer to use a simple and inexpensive technique to assess the day to day DLI values of PAR in a greenhouse accurately using just an inexpensive light meter.The present paper also proposes a more efficient way of using LED light panels in a hydroponic system.By moving the LED light panels closer to the crop,LED light source can use a fewer number of LEDs to produce the same required daily light requirement and can increase the efficiency of the power usage to more than 80%.Specifically,the present work has determined that it is important to design more efficient vertically movable LED light panels with capabilities of switching individual LEDs on and off,for the use in greenhouses.This allows a user to control the number of LEDs that can be lit at a particular time,as required.By doing so it is possible to increase the efficiency of a LED lighting system 展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFB0403901).
文摘High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing.One of the important ways to improve the quality of cucumber seedlings is to improve the light environment by using artificial light source.In this study,three cucumber seedlings(cv.Jintong,cv.Yunv and cv.Xiazhiguang)were grown for 23 d under eight levels of daily light integral(DLI)at 4.3 mol/(m^(2)·d),8.6 mol/(m^(2)·d),10.1 mol/(m^(2)·d),13.0 mol/(m^(2)·d),5.8 mol/(m^(2)·d),11.5 mol/(m^(2)·d),14.4 mol/(m^(2)·d)and 17.3 mol/(m^(2)·d),respectively.The results showed that when DLI was 14.4 mol/(m^(2)·d),the seedling height,stem diameter,total leaf area and shoot dry/fresh weight of all three cucumber cultivars reached the maximum,while hypocotyl length decreased with the increase of light intensity.When DLI was 14.4 mol/(m^(2)·d),Jintong and Xiazhiguang had the highest health index,which were 49.29 and 28.56,respectively,while that of Yunv was 81.59(DLI=14.4 mol/(m^(2)·d)).With the increase of DLI,the photosynthetic capacity of cucumber increases gradually.The highest net photosynthetic rate was shown at DLI of 14.4 mol/(m^(2)·d),while the chlorophyll content of cucumber seedlings of all three cultivars were less affected by DLI.Jintong and Yunv had the highest chlorophyll content when DLI was 8.6 mol/(m^(2)·d)because they were adapted to low-light environment.In conclusion,the DLI of 14.4 mol/(m^(2)·d)for Jintong and Xiazhiguang,while that of 17.3 mol/(m^(2)·d)for Yunv are suggested for the light environment design of factory-cultivated seedling for cucumber.
文摘Hydroponic farming is a viable and economical farming method,which can produce safe and healthy greens and vegetables conveniently and at a relatively low cost.It is essential to provide supplemental lighting for crops grown in greenhouses to meet the daily light requirement,Daily Light Integral(DLI).The present paper investigates how effectively and efficiently LEDs can be used as a light source in hydroponics.It is important for a hydroponic grower to assess the requirement of photo synthetically active radiation(PAR)or the Photosynthetic Photon Flux Density(PPFD),in a greenhouse,and adjust the quality and quantity of supplemental lighting accordingly.A Quantum sensor(or PAR sensor)can measure PAR more accurately than a digital light meter,which measures the light intensity or illuminance in the SI unit Lux,but a PAR sensor is relatively expensive and normally not affordable by an ordinary farmer.Therefore,based on the present investigation and experimental results,a very simple way to convert light intensity measured with a Lux meter into PAR is proposed,using a simple conversion factor(41.75 according to the present work).This allows a small-scale hydroponic farmer to use a simple and inexpensive technique to assess the day to day DLI values of PAR in a greenhouse accurately using just an inexpensive light meter.The present paper also proposes a more efficient way of using LED light panels in a hydroponic system.By moving the LED light panels closer to the crop,LED light source can use a fewer number of LEDs to produce the same required daily light requirement and can increase the efficiency of the power usage to more than 80%.Specifically,the present work has determined that it is important to design more efficient vertically movable LED light panels with capabilities of switching individual LEDs on and off,for the use in greenhouses.This allows a user to control the number of LEDs that can be lit at a particular time,as required.By doing so it is possible to increase the efficiency of a LED lighting system
