连作苎麻的部分生理生态特征及细胞学观察

采用盆栽试验,以中苎一号苎麻为材料,于2010、2011年研究不同连作年限(连作8～10年,A处理;连作4～5年,B处理;未种植过苎麻,对照)土壤栽植苎麻的生理生态及细胞学变化。结果表明:2010年不同处理苎麻的株高、茎粗、地上部和地下部干重差异不明显;2011年A处理二麻、三麻株高显著低于对照,茎粗、地上部干重极显著低于对照,连作障碍明显,障碍始于二麻,三麻收获期连作障碍加重,苎麻地下根系基本腐烂,麻株长到40 cm左右生长基本停滞;不同处理SOD活性和MDA含量在头麻、二麻差异不明显,A处理三麻SOD活性明显低于对照,MDA含量高于对照,植株细胞膜质过氧化作用明显,膜的正常结构和功能受到损伤,从而表现出障碍效应。连作4~5年土壤种植苎麻未表现出明显连作障碍。显微观察发现,连作引起麻根横切面内细胞密度降低,细胞排列疏松,并有细胞缺失,影响根系发育,苎麻从土壤中吸收养分和水分的能力降低,植株生长受阻。

Physio-ecological and cytological features of ramie from continuous cropping system

Variation of physio-ecological and cytological features in continuous cropping ramie soil for 8?10,4?5,1 years in Zhongzhu No.1 as material was studied by pot experiments for 2 years.The results showed that the plant height,stem diameter,shoot and root dry weight difference are not obvious in different treatments in 2010;but in the 2011 year,the plant height of A,B and C treatments are respectively to 50.2 cm,104.6 cm,112.6 cm in the secondly cropping period,A treatment was significantly lower than B,C,the stem diameter also showed the same laws;the shoot and root dry weight,A treatment was basically decay;the SOD activity and MDA content of three deal were no obvious differences in the firstly cropping and secondly cropping period of ramie,during the thirdly cropping period,the SOD activity of A treatment was significantly lower than B,C,the content of MDA is higher than that of B,C deal.in the 2010 and 2011years culture experiment,the continuous cropping obstacle effect in 8?10 years soil was significantly more than that of other tested soil,the continuous cropping obstacle on ramie occurred at seedling stage of the secondly cropping,the thirdly cropping stage are the most serious,root rot and retarded growth of the plants at 40 cm.Cytomorphological studies indicated that cell density reduced,cell arrangement loosely in the transverse section of ramie root caused by continuous cropping,and consequently affected root growth,reduced the absorb ability of nutrients and water from soil,retarded growth of the ramie plants.The plasamembrane lipid peroxidation of the plants led to impaired structure and function of plant cells under continuous cropping,it was suggested that there was a more inharmonious sink-source relation of ramie at the stressful condition of continuous cropping for 8?10 years,the so-called continuous cropping obstacle effect.