Root morphology, productivity, and photosynthesis of aeroponically grown ice plants (Mesembryanthemum crystallinum) with different nutrient spraying intervals

Title : Root morphology, productivity, and photosynthesis of aeroponically grown ice plants (Mesembryanthemum crystallinum) with different nutrient spraying intervals

Abstract:

Mesembryanthemum crystallinum (common name: ice plant) is a succulent plant native to South Africa. It has high nutritional values and has been successfully grown in the greenhouse in Japan and Taiwan undercooling temperature. Recently we have also grown this plant successfully in a  tropical greenhouse by cooling the root-zone only or indoor at cooling temperature under different combinations of LED-lighting.  Our results also showed that this facultative CAM (crassulacean acid metabolism) plant performed C₃ photosynthesis when supplied with adequate water. Although it is drought- and salt-tolerant species, there is very little work done on the effects of water and nutrient supply on this vegetable crop. This project aimed to investigate the impacts of nutrient spraying intervals on root morphology, productivity, and photosynthesis. In this project, all seedlings were grown for 4 weeks in small trays before transferring to aeroponic systems with different nutrient spraying intervals. In terms of root morphology and productivity, the longer nutrient spraying intervals such as 30, 60 and 240 min resulted in reductions of total root length, total root surface area and the total number of root tips, and a smaller mass of root and shoot compared to a shorter interval of 5 min. A decline in photosynthetic light use efficiency measured by chlorophyll fluorescence parameters demonstrated that plants grown under longer nutrient spraying intervals utilized lesser light energy and did not dissipate heat as effectively as those sprayed with nutrient solution for 5 min interval. Photosynthetic CO₂ assimilation rate (A_sat), stomatal conductance and internal CO₂ concentration were significantly reduced for plants grown under 240 min nutrient spraying interval, indicating signs of drought stress. All other plants had similar values of saturated photosynthetic O₂ evolution rate (P_max), A_sat, total reduced nitrogen and Rubisco concentrations. However, higher total chlorophyll concentration in plants grown under 240 min nutrient spraying interval imply that chlorophyll could be a mean of storing nitrogen.

Take Away Notes:
• The talk will illustrate how data produced by a research team or facilities, can be managed for long term use and reuse.
• It will present an example of data produced at large scale, such as genotyping data and how the tool is able to manage the different categories of genotyping technologies (Arrays, GBS).
• It will present a software based on the framework Django and python language, that is simple to learn for young bioinformaticians and a web software that is easy to use for scientists to fill it with data in autonomy and to query it.. • For research purpose, it will show how this tool can be useful either i) to make dashboards and inventories of data, or ii) to store different experiments coming from several technologies and different levels of data (raw and elaborated data) and how iii) to extract data useful for analysis software and for new experimental designs.
• To conclude, it will present a use case for plant breeding and diversity analysis, based on maize data, that allows to combine results coming from genotyping and phenotyping experiments, to help to find in plant germplasm collections, alleles, markers for traits of agronomical interest, to face for example, to challenges such as climatic changes.

Biography:

Dr. He Jie obtained her Ph.D. from Macquarie University, Australia in 1991. She is currently an Associate Professor at Nanyang Technological University, Singapore. She has more than 30 years of research experience in plant physiology. She has been actively involved in the research on responses of plants to environmental stresses (temperature, drought, light, UVB radiation). Her research interests are 1) photosynthesis (chlorophyll fluorescence, Rubisco protein); 2) shoot-root communication (C partitioning, nutrient uptake and N metabolism; 3) effects of root-zone temperature on aeroponically grown temperate crops in the tropics; 4) impacts of LED quality and quantity on photosynthesis and vegetable production.