Preliminary Study On The Invade Plasticity Of Cenchrus Calyculatus Cav.

Cenchrus calyculatus Cav.belongs to Gramineae,Cenchrus L.,is an annual herb.It was found in kezuohouqi of Tongliao in Inner Mongolia in the 1970 s,spreading widely in the surrounding areas and causing great harm to local agriculture and animal husbandry.According to some earlier surveys,the range of diffusion was increasing year by year,the degree of harm became heavier.However,few studies had been done on adaptability of the invasion.For this reason,this paper studied the phenotypic characters,the ultrastructure of seeds and photosynthetic characteristics of C.calyculatus Cav.in different distribution areas of Tongliao in Inner Mongolia.The results were as follows:1.There were differences in plant height,leaves length,leaves width and the leaves length-width ratio of Cenchrus calyculatus Cav.at seedl-ing stage,heading stage and mature stage in different distribution areas,and showed significant variability.The coefficient of variation of plant height and leaves length-width ratio all showed change rules in seedling stage>mature stage>heading stage.The variation coefficient of plant height was 4.97%~18.61%,and leaves length-width ratio was 7.12% ~ 21.52% at seedling stage.2.C.calyculatus Cav.seeds were significant differences on the length,width and length-width ratio in different distribution areas.The variation coefficient of length width ratio reached 35.71%-68.75%,and the largest was Ganqika Town of Kezuohouqi,reached 68.75%.At anatomical lens,the seeds colour were yellow and brown.Observed under the scanning electron microscopy that:At 30×magnification,the seeds surface were rough of Baxian Town of Naimanqi;At 100× magnification,the seeds were abnormity reticulate pattern in Kulun Town of Kulunqi and Baxian Town of Naimanqi,were strations in Dong mandou of Kezuohouqi and Ganqika Town of Kezuohouqi,were meridian and collaterals in Daolaodai three country of Daqingtala in Naimanqi;At 200× magnification,the seeds appeared clear gully in Baxian Town of Naimanqi and Daolaodai three country of Daqingtala in Naimanqi,appeared chewing the seeds of in Kulun Town of Kulunqi and Dong mandou of Kezuohouqi,appeared reticulation in Ganqika Town of Kezuohouqi.At 600× magnification,A ravine,a false hole between the seed stripes in Ganqika Town of Kezuohouqi and Dong mandou of Kezuohouqi,and paraffin protuberances of the tumor of Daolaodai three country of Daqingtala in Naimanqi.The difference of seed surface characteristics of C.calyculatus Cav.may be different invasion adaptability to different habitats.3.there were significant or even more significant difference of chlorophyll content of C.calyculatus Cav.at seedling stage,heading stage and mature stage in different distribution areas.The chlorophyll content was high and stable in Daolaodai three country of Daqingtala in Naimanqi and Tongliao district.There were differences in net photosynthetic rate,light compensation point,light saturation point and dark respiration rate at different growth stages.The net photosynthetic rate was large,the light saturation point was high,and the light compensation point was low in Daolaodai three country of Daqingtala in Naimanqi and Tongliao district.It showed that they had strong photosynthetic characteristics and could make use of light energy more efficiently in the seedling stage and the heading stage.They had strong phenotypic plasticity and could adapte to the invading habitat.