pOsNAR2.1:OsNAR2.1 expression enhances nitrogen uptake efficiency and grain yield in transgenic rice plantspOsNAR2.1:OsNAR2.1表达提高转基因水稻植株的氮吸收效率和籽粒产量PLANT BIOTECHNOLOGY JOURNALIF10.52017-03-2982OAAI