氮素对楸树无性系幼苗的生长影响研究

用沙培法培养楸树无性系I-4幼苗,进行4种供氮量（1 mmol/L、4 mmol/L、8 mmol/L、16 mmol/L）处理,对幼苗生长和部分生理性状进行试验。结果表明,对不同供氮量下苗木生长相比较,随着供氮量的增大,苗高呈先升高后降低的趋势,地径、叶片数、叶面积、茎、叶的生物量呈增大的趋势,而根冠比不断降低;叶绿素a、叶绿素b及类胡萝卜素含量升高,但蛋白质含量却不断降低。通过综合分析苗高、地径和生物量3个性状,确定楸树无性系I-4幼苗生长的最适氮浓度为16 mmol/L。

Growth Responses of Catalpa bungeito Nitrogen

Pot culture experiments were conducted to test the response of one year old Catalpa bungei C.A.Mey clone（I-4） to nitrogen application.Four tested nitrogen concentrations were 1 mmol/L,4 mmol/L,8 mmol/L and 16 mmol/L respectively.The experimental results with the increase of nitrogen application,the height growth showed the tendency of increase and then decrease,basal diameter,leaf number,leaf area and biomass increased with the increase of nitrogen application,whereas the root-top ratio decreased.Refers to the physical parameters,as the nitrogen applied increased,the contents of chlorophyll a,chlorophyll b and carotene increased,the contents of protein decreased on the contrary.Based on comprehensive analysis of height,basal diameter and biomass,it was concluded that the optimal nitrogen concentrations for one year old Catalpa bungei C.A.Mey clone（I-4） was 16 mmol/L.