烤烟光氮空间分布、光合特性及干物质积累对增密的响应OACSTPCD

To explore the effects of densification on the distribution of light andnitrogen,photosynthetic characteristics,dry matter accumulation and output value of flue-cured tobacco canopy in Shaoguan tobacco-growing area,four densities(M1:10500 plants/hm2,M2:13500 plants/hm2,M3:16500 plants/hm2,M4:19500 plants/hm2)of'Yueyan 97'were set to determine the light resources and nitrogen distribution,pigment content,dry matter accumulation and economic properties of different canopy.The results showed that with the increase of density,the light transmittal rate of different canopy decreased and the chlorophyll content was increased.Compared with M1 treatment,the upper leaf chlorophyll of M4 treatment increased by 26.31%at 80d,and the increase of Chlb was greater than that of Chla.Photosynthetic characteristics and nitrogen are important indexes of crop carbon and nitrogen metabolism.As density increased,photosynthetic rate of tobacco plant decreased,compared with M1 treatment,the upper leaves of M4 treatment decreased by 32.16%to 35.83%.The Ci,Tr and Gs increased first and then decreased,while nitrogen concentration showed a decreasing trend,but there was no significant difference between middle and upper leaves of M4,M3 and M2 treatment at different periods.When the density was 16500 plants/hm2,the dry matter accumulation in leaf organs of'Yueyan 97'reached the maximum,and the highest yield and economic benefit were obtained.Compared with the density of 10500 plants/hm2,the yield and output value were significantly increased.Reasonable dense planting of'Yueyan 97'could resist the decline of photosynthetic rate under weak light stress by reducing chlorophyll degradation and improving nitrogen distribution in middle and upper leaves,promoted the dry matter accumulation ability of tobacco plant population,and obtained higher tobacco yield and output value.