苋菜的光合特性

宽菜Amaranthus cruentus cv.生长在调控的温室条件。在光强0至800μmol.m~(-2)S~(-1),光合速率(PN,μmol.CO_2m~(-2)、s~(-1))随光强(PFD,μmol、m~(-2)、s~(-1))增高而增大,其关系为PN=56.82 PFD×10~(-3)—2.13。光补偿点为60μmol.m~(-2)、s~(-1)。叶片在1400 μmol.m~(-2)、s~(-1)达到光合光饱和点。在叶温35℃,叶片/空气水蒸汽压陡度20 m Pa、Pa~(-1)和外界CO_2浓度340μ1、1~(-1),光饱和光合速率为51.63±4.90μ mol.CO_2、m~(-2)、S~(-1)。在光强0至600μmol.m~(-2)、s~(-1),气孔传道率随光强增高而增大。光强高于600μmol.m~(-2)、s~(-1),气孔传道率变化较小。细胞间CO_2浓度为120μ1.1~(-1)由于细胞间CO_2浓度在光合速率——CO_2关系曲线的转折点,可能表明光合作用不受气孔限制。结果表明,苋菜适于高光强环境生长,在干旱条件下具有高的光合速率。

PHOTOSYNTHETIC CHARACTERISTICS OF AMARANTHUS CRUENTUS CV.PHOTOSYNTHETIC CHARACTERISTICS OF AMARANTHUS CRUENTUS CV.

Plants of Amananthus cruentus cv.were grown under greenhouse condition that was controlled to mimic natural environmental condition.At incident quantum flux of 0 to 800μmol.m-2.s-1,photosynthetic rate increased as light intensity enhanced.The relationship between photosynthetic rate(PN,umol.CO2 m-2 s-1)and light intensity(PFD,μmol.m-2.s-1)was PN=56.82.PFD.10-3-2.13 and light compensation point occurred at 60μmol.m-2.s-1 A photosynthetic rate of 51.63±4.90μmol.CO2.m-2.s-1 was measured at the temperature optimum(35℃).At incident photon flux 0 to 600μmol.m-2.s-1,leaf conductance increased as light.intensity increased,but there was a small dependence of leaf conductance on light intensity beyond 600μmol.m-2.s-1.The intercellular CO2 concentration was typical for C4 plant(120μ.1.1-1).Photosynthetic rate in Amaranthus cruentus was not sensitive to the change of the leaf/air water vapor gradient and in this case leaf conductance decreased slightly.The results suggest that Amaranthus cruentus can adapt the higher light condition and has high photosynthesis in dry environment.Plants of Amananthus cruentus cv.were grown under greenhouse condition that was controlled to mimic natural environmental condition.At incident quantum flux of 0 to 800μmol.m-2.s-1,photosynthetic rate increased as light intensity enhanced.The relationship between photosynthetic rate(PN,umol.CO2 m-2 s-1)and light intensity(PFD,μmol.m-2.s-1)was PN=56.82.PFD.10-3-2.13 and light compensation point occurred at 60μmol.m-2.s-1 A photosynthetic rate of 51.63±4.90μmol.CO2.m-2.s-1 was measured at the temperature optimum(35℃).At incident photon flux 0 to 600μmol.m-2.s-1,leaf conductance increased as light.intensity increased,but there was a small dependence of leaf conductance on light intensity beyond 600μmol.m-2.s-1.The intercellular CO2 concentration was typical for C4 plant(120μ.1.1-1).Photosynthetic rate in Amaranthus cruentus was not sensitive to the change of the leaf/air water vapor gradient and in this case leaf conductance decreased slightly.The results suggest that Amaranthus cruentus can adapt the higher light condition and has high photosynthesis in dry environment.