Germination responses and boron accumulation in germplasm from Chile and the United States grown with boron-enriched water

Boron (B) is toxic to most plant species when accumulated in high concentra tions. Differences in a plant's ability to adapt to high concentrations of B may depend on the origin of the germplasm. Chilean and domestic (U.S.)ger mplasm, corn (Zea mays L.), carrots (Daucus carotas), tomato (Lycopersicum esculentum L,), and alfalfa (Medicago sativa L.) were evaluated for germina tion, emergence of cotyledonary leaves, and tissue B accumulation under hig h-is conditions in both an environmental growth chamber and a greenhouse. I ncreasing B levels (20-40 mg B liter(-1)) inhibited the percentage germinat ion for both the Chilean and domestic germplasm. Chilean germplasm exhibite d generally a greater percentage of healthy cotyledonary leaves at the 20 m g B liter(-1) treatment than the domestic germplasm. Comparing B concentrat ions between both germplasm grown and irrigated with B-enriched water (10-2 0 mg B liter(-1)) under greenhouse conditions, leaves from domestic germpla sm contained more B. Moreover, B troxicity symptoms were more severe for th e tested plant species from the domestic germplasm. Apparent B tolerance by germplasm of different origin should be further tested under field conditi ons. (C) 1999 Academic Press.