核桃油脂转化期树下光环境的时空变化研究

Spatiotemporal Variation of Light Environment under Walnut Trees During Oil Synthesis Period

以太行山南簏低丘山区5年生和10年生核桃为研究对象,利用ASD便携式光谱仪对核桃油脂转化期树下不同空间光强、光质及消减率进行测算,结果显示:①5、10 a核桃树下的光合有效辐射均在中午12:00达到最大值,在空间上表现为在距树2.5 m(树行中间)处最大,树行内西侧各处消减率均高于对应的东侧各处;5、10 a核桃树下光合有效辐射相对CK分别减少了60.12%和77.68%.②两种林龄核桃树下红外波段内各光质在时间和空间上均表现为远红外光比例>近红外光比例;光合有效辐射波段内各光质在日内不同时刻均表现为黄绿光比例>蓝紫光比例>红橙光比例,空间上5 a核桃树下各测点均表现为黄绿光比例>蓝紫光比例>红橙光比例,10 a核桃树下各测点黄绿光比例最大,距树1.5~2.5 m范围内表现为蓝紫光比例>红橙光比例,其余为红橙光比例>蓝紫光比例.其中蓝紫光在5 a和10 a均表现为消减率最大,且两种林龄核桃树下差异显著(P<0.05).不同林龄核桃树下不同时间、空间处的光环境各不相同,因此在生产实践中可根据树下光环境的差异选择适宜树下种植的作物.

Taking 5-year-old and 10-year-old walnut trees in the southern part of Taihang Mountain as experiment materials,the temporal and spatial variation characteristics of light intensity,light quality and reduction rate under different age walnut trees during oil synthesis period were measured by the ASD portable spectrometer. The results were as follows:①Photosynthetically active radiation under the 5-year-old and 10-year-old walnut trees both reached maximum at 12:00,and their peak values in space distribution appeared at 2.5 m from the trees(the middle of the tree row. The reduction rates on the west side of the tree line were higher than those on the east side;Photosynthetically active radiation under the 5-year-old and 10-year-old walnut trees decreased by 60.12% and77.68%,respectively,compared with CK. ②The light quality of infrared ray under two ages’ walnut trees showed as far infrared ray ratio> near infrared ray ratio at different time and space. The yellow-green light ratio> blue-violet light ratio> red-orange light ratio of photosynthetically active radiation under two ages’ walnut trees at different moments in the day. In the space,all points show that yellow-green light ratio> blue-violet light ratio> red-orange light ratio under 5-year-old walnut trees,yellow-green light ratio is greatest under 10-year-old walnut trees,while red-orange light ratio> Blue-violet light ratio except the distance 1.5-2.5 m under 10-year-old walnut trees. The reduction rate of blue-violet light was the largest in 5-year-old and 10-year-old walnut trees,and the difference of blue-violet light ratio was the largest under two ages’ walnut trees. The light quality under two ages’ walnut trees,showed variation due to time,and space,which could provide some evidence for selecting suitable plants in the undergrowth economy model.