The germination and seedling growth responses of wheat and maize to drought and low temperature

Spring drought and low temperature in northeast China are the main climate stresses influencing crop growth.In this paper,we selected two crops,wheat and maize,to simulate the effects of single and combined stresses of spring drought and low temperature on germination and early seedlings growth of the two crops.The results showed that,both single and their interaction would significantly influence the germination and early seedlings growth of wheat and maize.Wheat seeds maintained a higher germination percentage of 63.3%-87.3% with PEG under 15-25 ℃ and 0-20%,but sharply reduced by 30% with PEG under 10 ℃,respectively.The germination percentages with different levels of PEG under 10 ℃ and 30% PEG under different temperature levels were 0-64.7% and 0-18%,respectively.The germination percentage of maize seeds was 2.22%-100% with 0-20% PEG under 15-25 ℃,but the germination percentage was zero with 30% PEG under 10 ℃.The wheat length and biomass of early seedling changed in a similar trend to germination with increased drought and decreased temperature,and the peak value was obtained with 10% PEG under 20℃.The changes of maize seedling length and biomass were consistent with the germination change,and the peak value was obtained without PEG under 25℃.Root/shoot ratio of wheat was higher than that of corn,which indicated that wheat would germinate and grow better than corn under lower temperature and stronger drought.More root biomass and higher root/shoot ratio would be adaptive strategies for wheat seedlings to low temperature and drought stresses.