Osmotic priming increases seed germination of Amaranthus caudatus L. at low temperature

Seeds of Amaranthus caudatus L. were primed with four media at various concentrations [1, 2 or 3% (wv(-1)) of KNO3, NaCl, or boric acid]; or, 100, 200 or 300 gL(-1) poly-ethylene glycol (PEG 6000, for 4, 7 or 10 days) at 20 degrees C. Four replicates of 100 seeds were incubated in darkness at 15oC. Priming treatments improved differently final germination percentage, germination rate and uniformity of Amaranthus caudatus L. at low temperature. The highest final germination percentage was obtained from seeds primed with 3% (wv(-1)) NaCl for 4 days while seeds primed with 2% (wv(-1)) NaCl for either 7 or 10 days had the fastest germination. This study revealed that priming seeds in 3% (wv(-1)) boric acid significantly improved germination rate and uniformity of A. caudatus at 15 degrees C.