HK studies the immediate molecular switches by which plants sense changes in the environment, such as responses to elevated CO2, drought (VPD), and air pollutant ozone. Within past years he has been applying this knowledge for creating plants that would consume less water and display improved tolerance to abiotic stress. He is leading Estonian Research Infrastructure Roadmap project to develop installations that foster experimental work with agricultural species in Estonian research institutions. He is also developing technologies for measuring plant gas exchange in various growth conditions in the frames of spin-off company PlantInvent.