Effect of water bloom-forming cyanobacterial bio-substances on the growth of submerged macrophyte Ceratophyllum oryzetorum Kom
水华蓝藻生物质对沉水植物五刺金鱼藻生长的影响

The different forms of cyanobacterial bio-substances on the growth and photosynthetic activity of submerged macrophyte Ceratophyllum oryzetorum Kom was investigated in present study.Results showed that all kinds of cyanobacterial bio-substances ould enhance the growth of C.oryzetorum Kom.differently.Compared with the control,the plant length of C.oryzetorum could be increased by all forms of bio-substances,in which the dry algal material has the strongest effect,while the decomposed material has the lowest.The fresh weight of C.oryzetorum also could be promoted by all kinds of algal bio-substances,in which the dry algal material and the fresh algal material almost have the same obvious effect,and the decomposed algal material has the lowest,while in control,the fresh weight firstly increased,and then decreased.All forms of cyanobacerial material could promote the increase of branches in C.oryzetorum,in which the fresh algal material has the strongest effect and the dry and decomposed materials lower,while in control,the branches increased also less than the algal material treated groups.The photosynthetic activity expressed by chlorophyll fluorescence suggested that the dry algal material treated C.oryzetorum had the highest activity,and the fresh algae treated one lower,and the decomposed algae and the control treated ones were the lowest.In conclusion,the different forms of cyanobacterial bio-substances could supply nutrients or growth promoters for C.oryzetorum to grow,and at the same time, other growth inhibiters might exist to inhibit the growth of C.oryzetorum.Factors of promoting and inhibiting worked together,thus resulted in the different promoting effects by different forms of cyanobacterial bio-substances to the growth in C.oryzetorum.