不同气孔密度水稻剑叶光合特性及蔗糖代谢研究

以叶片不同气孔密度(高、中和低气孔密度)水稻品系为试验材料,在齐穗期研究水稻剑叶光合特性、糖分含量和蔗糖代谢酶活性。结果表明,水稻叶片中蔗糖含量、蔗糖磷酸合成酶活性与气孔密度呈极显著正相关;蔗糖合成酶活性与气孔密度呈显著正相关。高气孔密度水稻叶片Rubisco活性、净光合速率、蔗糖含量、蔗糖磷酸合成酶和蔗糖合成酶活性显著高于低气孔密度水稻;不同叶片气孔密度与中性转化酶呈显著负相关。研究认为,气孔密度增加提高了水稻叶片光合效率,促进了蔗糖积累及蔗糖代谢酶活性提高,有利于更多光合产物——蔗糖向籽粒转运。

Photosynthetic Characteristics and Sucrose Metabolism of Rice Flag Leaf with Different Stomatal Densities

Three rice lines with different leaf stomatal densities(high, medium and low) were used to study photosynthetic characteristics, sucrose content and the activities of sucrose metabolizing enzymes in flag leaf at full heading stage. The results showed that the content of sucrose and the activity of sucrose phosphate synthase (SPS) in rice flag leaves were extremely significantly and positively correlated with stomatal density, and the activity of sucrose synthase (SS) was significantly positively correlated with stomatal density. Rubisco activity,net photosynthetic rate,sucrose content,SPS and SS in rice leaves with high stomatal density were significantly higher than those in rice leaves with low stomatal density, while negatively correlated with the activity of neutral invertase (NI). These results showed that increased stomatal density improved the photosynthetic efficiency, the sucrose accumulation and the activities of SPS and SS, which contributed to photosynthate(sucrose) transport to grains.