4种木瓜品种的呼吸作用以及其耐荫性研究

Respiration and Shade-tolerance of the Four New Carica papaya Linn Genotypes

对4种木瓜Carica papaya Linn新品种台农2号(TL2)、台农6号(TL6)、龙珠(LZ)和夏威夷(H)的呼吸作用进行了观测,结果表明:①净光合速率高的呼吸速率也强。净光合速率(A_n)4个品种高低排列依次为H≥TL2≥TL6≥LZ,而暗呼吸速率(R_d)为H≥TL6≥TL2≥LZ。R_d/A_n从高到低依次排列为LZ≥TL6≥H≥TL6。②通过网室内4种木瓜的光合量子产量比较LZ≥H≥TL6≥TL2,结合其暗呼吸速率光合速率,说明LZ的耐荫性最好,而H则应该较为喜阳。其它种则差异不显著。③呼吸速率与光强呈显著正相关,而光强过高时则下降,呼吸速率与气温呈显著负相关(P≤0.05)。④网室栽培有助于木瓜避开华南地区中午高温、强光以及高湿的胁迫,避免“午休”,减少呼吸损失,积累更多碳同化产物。

The respiration of the four new genotypes of Carica papaya Linn (TL2, TL6, H and LZ) was measured, the results showed that: (1)The dark respiration rate (Rd) increased coupled with the photosynthetic rate (An). The values of An arranged in this sequence: H≥TL2≥TL6≥LZ, (Rd) H≥TL6≥TL2≥LZ and Rd/An LZ ≥ TL6 3≥H ≥ TL6. (2)The quantum yield efficiency of the four genotypes arranged in the sequence of LZ>H>TL6>TL2, combined with their Rd and An, it could infer that LZ was the most shade-tolerant genotype and H was a sunny genotype, but the other two genotypes had no significant differences (P<0.05). (3)Rd had the positive relationship with PFD, but PFD increased to more than 1500 μmol-m-2·s-1 , Rd reduced, Rd also significantly related positively with 0 (P<0.05). (4) Network will be helpful for C.papaya escape from high temperature, PFD and high humidity, release from 'noon break', reduce the damage by respiration, increase the carbon fixation and the production.