My overall research goal is to improve crop yield, quality, and resource use efficiency in field and in greenhouse production systems by exploiting plant adaptation mechanisms to environmental perturbations in a future warmer, drier and CO2-enriched climate.
Past research focuses and achievements
My research during the last 20 years had been focused on the physiological and biochemical regulation of growth and functioning of crop plants subjected to major abiotic stresses including drought, heat, cold and salinity, individually or in combination. I have given much attention to the relative importance of hydraulic and chemical influences on crop vegetative and reproductive physiology under drought/heat/cold stresses. My post-doctoral research (2004-2007) financed by the Danish Research Council (SJVF, 23-03-0208, 2004-2007) and by the European Commission (SAFIR, EU, INCO-CT-2004-509163, 2005-2009) was on exploiting the physiological mechanisms for enhancing crop water use efficiency in both horticultural and field crops during deficit irrigation strategies. The research ideas were latterly tested in projects of my Ph.D. students from 2008 to 2015. By integrating the knowledge of crop physiology, agronomy and soil science, my research aimed to understand the processes occurring at the interfaces between crops and their environments; and to develop mechanistic models in order to optimize water-saving deficit irrigation strategies to enhance crop yield/quality and simultaneously improve resource use efficiency. The scientific publications (see publication list) based on my research findings have made significant contribution to the literature and which have increased our knowledge about:
- The role of abscisic acid (ABA) based root-to-shoot signaling in regulating stomatal conductance and its exploitation to enhance water use efficiency during deficit irrigation
- The effects of soil water dynamics under the partial root-zone drying (PRD) irrigation on C, N and P dynamics in the soil-plant systems
- Plasticity of stomatal morphology to irrigation and N and P fertilization regimes and its implication in optimizing water use efficiency
- The underlying mechanisms for enhancing fruit calcium (Ca) content and fruit quality of tomato under PRD
- The role of biochar amendment in enhancing crop salt tolerance and water use efficiency
Current research focuses
Currently, my research lies at investigating the effect of biochar amendment on soil P bioavailability and root to shoot signalling of plants during soil drying. Focus has also been on exploring physiological and biochemical mechanisms of crop plants response to major abiotic stresses in future climate change scenarios. These comprise the following four aspects:
- Illustrated how biochar and soil properties jointly affect P bioavailability and plant nutrients uptake. Our research illustrated the specific effect of different biochars on the chemical and biological P processes in varied soils by affecting P sorption processes, increasing the available P content, and affecting P mineralization and solubilization processes. We have also shown, for the first time in literature, that biochar addition could influence the stoichiometry of plants due to its modification of mineral nutrients supply and influence on minerals uptake.
- Priming-mediated stress tolerance and cross-stress tolerance in crop plants. At molecular, biochemical and physiological levels, we demonstrated, among the first researchers in the world, that drought, low temperature, and high temperature priming at earlier growth stages of wheat plants could enhance tolerance or cross-tolerance to subsequent stresses at reproductive stages. I elucidated the role of melatonin in stress memory and cold tolerance in barley and wheat.
- CO2 elevation modulates the response of crop plants to drought, cold, heat and salinity stress. For the first time in literature, we reported that stomata of tomato become less sensitive to ABA signaling when grown at elevated CO2, and there is a shift from chemical towards hydraulic in stomatal control of the plants grown at ambient vs. elevated CO2 during soil drying. In addition, using an ABA-deficient mutant, we revealed that tomato plants grown at elevated CO2 had significantly lower leaf and root hydraulic conductance, which was associated with down-regulation of gene expression for aquaporin (i.e., PIPs) and this process, is ABA-dependent. Besides, we showed that grown at elevated CO2 could enhance tolerant to drought, salinity, cold and heat stresses across different crop species.
- Multi-generational effect of CO2 elevation on crop water relations and grain quality. For the first time in literature, we revealed that after four generations continuously grown at elevated CO2, the WUE and shoot biomass and grain yield of wheat plants were enhanced while the grain quality attributes (e.g., minerals and protein) were declined along with the progress of the generations. Our findings highlighted the risk of potential ‘hidden hunger’ in future CO2-enriched climate.
Future research plan
My research vision is to reveal and exploit the physiological and genotypic resilience mechanisms of major crop plants in response to climate changes scenarios, e.g., co-occurrence of multiple abiotic stresses (drought, heat, and salinity) at elevated CO2. My core hypothesis is that physiological and genetic responses to multiple abiotic stresses are integrated by complex regulatory network that influence the processes important for yield and quality formation, and which can be revealed by combing modern genotyping and advanced phenotyping technologies. Thus, I will pursue an interdisciplinary approach to:
- Identify the complex crosstalk between physiological and genetic responses to elevated CO2 and multiple abiotic stresses. The main processes to be investigated are the root-shoot communication and coordination in the regulation of plant water balance, the source and sink dynamics of C and N metabolism, and the rhizosphere process of N, P transformation and acquisition.
- Reveal the epigenetic mechanisms of intra/intergenerational stress priming and memory for enhanced stress tolerance.
- Investigate the role of plant growth promoting rhizobacteria (PGPR) on stress resilience and nutrient uptake in a CO2-enriched environment.
- Develop novel irrigation and fertilization strategies to enhance resilience of crops (in terms of both yield and quality) to multiple abiotic stresses as well as under elevated CO2 growth conditions.
- Establish a Robust Crops Centre as a spearhead breakthrough research by imposing realistic multi-stress conditions using state-of-the-art climate-controlled growth chambers, semi-field greenhouses and instrumented field trials.