每两个月一次的

Plants were hydroponically grown in solutions containing 3 mM Ca(NO3)2 or 3 mM NH4NO3 as nitrogen source. Mature plants were harvested eight times in one day at a 3 hr. interval from 8:00PM Aug. 12 to 5:00PM Aug. 13. Diurnal variations of the shoot nitrate content were observed in either Ca(NO3)2 or NH4NO3 treatment. Shoot nitrate content of Ca(NO3)2 treated plants were higher than those treated with NH4NO3 at every harvest. The average shoot nitrate content of lettuce with Ca(NO3)2 was 0.68% of the dry weight, and it was 0.29% for the NH4NO3 treated lettuce. The fresh weight of the NH4NO3 treated lettuce were 1.43 or 1.2 fold heavier than those with Ca(NO3)2 treatment for shoot or root respectively.

R36品种以3mM硝酸钙(6mM N)或3mM硝酸铵(6mM N)处理，於8月12日下午8点开始采收，每隔3小时采收一次，采收至8月13日下午5点。3mM硝酸钙与3硝酸铵两种养液处理的地上部硝态氮含量皆有日变化，而且在8个采收时间，3mM硝酸钙养液处理的地上部硝态含量皆高於3mM硝酸铵处理。8个采收时间的硝态氮含量平均，3mM硝酸钙养液为乾物含量的0.68%，而3mM硝酸铵处理为0.29%。3mM硝酸铵养液处理的地上部与根部鲜重分别为3mM硝酸钙处理的1.43倍及1.2倍。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。