Research Projects

Under salinity, plants optimize nutrient and water uptake by roots at the expense of excess salt in the soil. Halophytes like Avicennia marina secrete sodium through leaves, compartmentalize it in special subcellular structures, and accumulate osmotic counteracting ions to balance excess sodium ions. Mangrove species like A. marina have complex root systems, investing substantial carbon below ground to provide anchorage, slow incoming tidal waters, and accumulate organic/inorganic sediment. Understanding how roots of A. marina sense and respond to salinity is crucial to understanding how much of their carbon gain is invested in roots to absorb nutrients, minerals, and oxygen optimally. Seedling establishment in A. marina is vital for anchorage and nutrient absorption. A. marina seeds are large, recalcitrant, and fleshy, with a hypocotyl that elongates during germination and a supporting root arising from multiple root primordia at the distal end. The emergence of the next two or three roots is spatially and temporally determined, with a triangulation/tripod of the first three roots being crucial for overall balance and anchorage. This proposal examines the diversity in root traits for seedling establishment in A. marina using physiological, morpho-anatomical, ionomic, and transcriptomic approaches. Split root systems (SRS) suggest that A. marina responds to transient freshwater patches by increasing water uptake from areas where the salinity is better for growth. The second component of the proposal examines how heterogeneous salinity application affects root traits and function in A. marina, following seedling establishment.