黑藻与苦草在不同水深下光合作用的比较研究

以沉水植物较为丰富的洪湖凹沟子作为采样区域，利用水下调制荧光仪研究洪湖常见的2种高耐污、高吸污水鳖科沉水植物黑藻（ Hydrilla verticillata（ L. f.）Royle）与苦草（ vallisneria natans（ Lour.）Hara）分别在100 cm及50 cm水深条件下光合作用的差异.结果表明:在100 cm水深条件下，当PAr值稳定为342μmol·m-2·s-1时，黑藻（Hydrilla verticillata）的ETr值趋近25.10μmol·m-2·s-1，而苦草（vallis-neria natans）的ETr值趋近10.10μmol·m-2·s-1；当PAR渐强时，黑藻在PAr值为219μmol·m-2· s-1时其ETr达到峰值21.76μmol·m-2·s-1，苦草在PAr值为515μmol·m-2·s-1时其ETR达到峰值12.65μmol·m-2·s-1；在50 cm水深条件下，当PAr值稳定为342μmol·m-2·s-1时，黑藻的ETr值趋近26.20μmol·m-2·s-1，而苦草的ETr值趋近11.90μmol·m-2·s-1；当PAr渐强时，黑藻在PAr值为219μmol·m-2·s-1时其ETr达到峰值25.27μmol·m-2·s-1，苦草在PAr值为1042μmol· m-2·s-1时其ETr达到峰值4.80μmol·m-2·s-1.综上所述，在100 cm或50 cm水深条件下，黑藻的光合作用强度皆强于苦草.

The Comparative Study on Photosynthesis of Hydrilla verticillata and Vallisneria natans in the Different Depth

Chosen the Wagouzi site with abundant submerged population in the Honghu Lake as a sampling region, the difference of photosynthesis of submerged macrophytes Hydrilla verticillata( L. f. )Royle and vallisneria natans ( Lour. )Hara which are high resistance and obsorption to the dirty water in Honghu Lake was designed to research their response in the 100 cm and 50 cm water depth by Diving-PAM apparatus. The results showed that the value of External Transfer Rate(ETR)of Hydrilla verticillata and vallisneria natans separately approached to 25. 1 μmol· m-2 · s-1 and 10 . 1 μmol · m-2 · s-1 when the value of Photosynthetic Active Radiation( PAR )was stable for 342 μmol·m-2 · s-1 under the condition of 100 cm water depth. With the PAr intensity gradually becoming strong,ETr of Hydrilla verticillata reached its peak 21. 76 μmol·m-2 ·s-1 when the PAr value was 219 μmol· m-2 ·s-1 ,as well as ETr of vallisneria natans reached its peak 12. 65 μmol·m-2 ·s-1 when the PAr value was 515 μmol·m-2 ·s-1 . On the other hand,the value of ETr of Hydrilla verticillata and vallisneria natans separately approached to 26. 2 μmol·m-2 ·s-1 and 11. 9 μmol·m-2 ·s-1 when the value of PAr was stable for 515 μmol· m-2 ·s-1 under the condition of 50 cm water depth. With the PAr intensity gradually becoming strong,ETr of Hydrilla verticillata reached its peak 25. 27 μmol·m-2 ·s-1 when the PAr value was 219 μmol·m-2 ·s-1 ,as well as ETr of vallisneria natans reached its peak 4. 80 μmol·m-2 ·s-1 when the PAr value was 1 042 μmol· m-2 ·s-1 . In summary,no matter in 100 cm or 50 cm water depth condition,photosynthesis intensity of Hydrilla verticillata is stronger than that of vallisneria natans.