Spatial and temporal characteristics of photosynthetic capacity and nutrient concentrations in different canopy layers of poplar Ⅰ-69
Microclimate,photosynthetic characteristics,photosynthetic area and nutrient concentrations in different canopy layers were measured to make a comprehensive evaluation of leaves growth for poplar Ⅰ-69(Populus deltoides Bartr.cv.‘Lux’).The results showed that the photosynthetic characteristics were better in July and August than in May and September.The net photosynthetic rate,average area of single leaf and leaf area of single layer were in the order of canopy layer Ⅲ＞ canopy layer Ⅱ ＞canopy layer Ⅰ.Foliar nutrient concentrations in the different canopy layers varied with the month.Nitrogen and phosphorus concentrations appeared an overall downward trend from June to October.Potassium concentration increased before August and after then decreased gradually.Calcium concentration showed the upward trend from June to October.The relative approach degree calculated by TOPSIS for canopy layer Ⅰ,Ⅱ,Ⅲ were 0.163,0.625 and 0.785,respectively,indicating that the leaves growth condition of the different canopy layers were significantly different.The growth condition of leaves in canopy layer Ⅱ and Ⅲ were obviously better than that in canopy layer Ⅰ.
Populus deltoides Bartr.cv.‘Lux’canopy layerphotosynthetic capacitynutrient concentrations
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