Citizens AND HYdrology (CANDHY): conceptualizing a transdisciplinary framework for citizen science addressing hydrological challenges

Widely available digital technologies are empowering citizens who are increasingly well informed and involved in numerous water, climate, and environmental challenges. Citizen science can serve many different purposes, from the "pleasure of doing science" to complementing observations, increasing scientific literacy, and supporting collaborative behaviour to solve specific water management problems. Still, procedures on how to incorporate citizens' knowledge effectively to inform policy and decision-making are lagging behind. Moreover, general conceptual frameworks are unavailable, preventing the widespread uptake of citizen science approaches for more participatory cross-sectorial water governance. In this work, we identify the shared constituents, interfaces, and interlinkages between hydrological sciences and other academic and non-academic disciplines in addressing water issues. Our goal is to conceptualize a transdisciplinary framework for valuing citizen science and advancing the hydrological sciences. Joint efforts between hydrological, computer, and social sciences are envisaged for integrating human sensing and behavioural mechanisms into the framework. Expanding opportunities of online communities complement the fundamental value of on-site surveying and indigenous knowledge. This work is promoted by the Citizens AND HYdrology (CANDHY) Working Group established by the International Association of Hydrological Sciences (IAHS)

Role of dehydrodiconiferyl alcohol glucosides in cytokinin-induced plant cell division

Cytokinins are a group of plant hormones which are essential for the division of cultured plant cells. They have a wide range of biological activities, but the biochemical bases for their control of cell division are not known and little is known about the potential signal transduction pathways that are utilized. In the late 1960s, a fraction was isolated from crown gall tumor cells of Vinca rosea which could substitute for cytokinins in plant cell culture systems. The structure of the compounds responsible for this activity were identified recently as six different isomers of dehydrodiconiferyl alcohol glucosides (DCGs). The biologically active isomers A and B were chemically synthesized and their biological activities examined. In cell division assays, the synthetic DCGs mimicked the plant-derived isomers, stimulating dose-dependent growth of tobacco leaf callus at concentrations ranging from 10 $\mu$M through the highest concentrations tested. The synthetic DCGs directly induced cell division of tobacco leaf callus. The DCGs were tested for their activity in other cytokinin bioassays, but were unable to induce shoot organogenesis of tobacco leaf explants nor stimulate betacyanin production in amaranth seedlings, even at concentrations up to 100 $\mu$M. Therefore, the DCGs seemed only to be able to replace the cytokinins in inducing cell division. To determine whether the DCGs have a role in endogenous cell division, DCG A + B levels were measured during cytokinin-induced growth of tobacco pith tissue. It was found that the cells began to divide after 3 to 4 days of cytokinin treatment, which is the same time the DCGs A + B began to accumulate. A block to DCG biosynthesis also correlated with an inhibition of growth suggesting that the DCGs are required for cell division to occur. Taking the pattern of DCG accumulation together with the fact that DCGs A/B can stimulate cell division when applied exogenously to cultured plant cells, it is possible to propose that the DCGs are one signal in the pathway of cytokinin-induced cell division