[Effects of different accumulated temperature on photosynthetic performances of spring maize varieties during grain-filling period].

Taking cold-resistant maize variety Fengdan 3 and cold-sensitive maize variety Zhengdan 958 as test materials, field experiments were conducted in I, II, and III accumulated temperature zones in Heilongjiang Province of Northeast China to study the effects of different accumulated temperature on the photosynthetic performances of different types of cold-resistant spring maize varieties during their grain-filling period. In the three accumulated temperature zones, the tasseling and maturing periods of Fengdan 3 and Zhengdan 958 were prolonged in the order of I > II > and III, and the grain bulk density decreased in the same order. The RuBPCase and PEPCase activities of Fengdan 3 and Zhengdan 958 leaves had different temperature sensitivity.

[Effects of PASP-KT-NAA on the grain-filling of maize in different accumulated temperature zones of Hilongjiang Province, Norheast China].

Taking the two maize varieties Zhengdan 958 and Fengdan 3 grown on the three accumulated temperature zones (I, II and III) in Heilongjiang Provice as test materials, a field investigation was made in 2010 and 2011 to study the effects of PASP-KT-NAA (PKN), a compound of exogenous plant growth regulators, on the grain filling and yield of the varieties under different environmental temperatures. From zone I to III, the air temperature at the grain filling stage had a decreasing trend, with the average minimum temperature being 12.16, 11.