短期根际不同CO2处理对番茄叶片光合日变化及植株生物量的影响

Effects of Short-term Different Root-zone CO_2 Concentrations on Diurnal Photosynthesis and Biomass of Tomato

采用气雾法栽培方式,在第1花序第1花开放时,对雾培番茄植株根际进行连续2周不同体积分数[370(CK)、2 500、5 000和10 000μL.L-1]的CO2处理,研究根际不同CO2处理对番茄叶片光合日变化及植株生物量的影响。结果表明,一天中,8:00-11:00,各处理和CK番茄叶片的净光合速率(Pn)和气孔导度(Gs)均呈上升趋势,且8:00-10:00各处理和CK的Pn和Gs均无显著性差异。随着温度和光照强度的增加,11:00-13:00,各处理和CK叶片的Pn、Gs和PSⅡ光化学效率(Fv/Fm)显著下降,13:00降至最低值,但此时各处理叶片的Pn和Fv/Fm均显著大于CK,Gs显著低于CK,且5 000μL.L-1和10 000μL.L-1处理的午间叶片相对含水量(RWC)显著高于CK,其中10 000μL.L-1处理的叶片Pn、Gs和RWC分别是CK的1.39、0.81和1.27倍。5 000和10 000μL.L-1处理的茎叶和根系的鲜、干质量均显著大于CK。2 500μL.L-1处理的生物量指标与CK差异不显著。由此可见,在高温、高光强条件下,提高根际CO2体积分数可以缓解雾培番茄叶片光合作用的"午休"现象,使植株的生物量显著增加。

The root zones（RZ） of tomato plants cultured by areoponics were treated for two weeks at the first flower anthesis stage with four different CO2 concentrations,including 370 μL·L-1（CK）,2 500 μL·L-1,5 000 μL·L-1,and 10 000 μL·L-1,to investigate the effect on diurnal photosynthesis and biomass.The results showed that net photosynthetic rate（Pn） and stomatal conductance（Gs） of all treatments and CK tended to increase from 8：00 to 11：00 but without significant differences.With the temperature and light intensity increase during 11：00-13：00,Pn,Gs and the photochemical efficiency of PSⅡ（Fv/Fm） of all treatments and CK decreased significantly.Pn,Gs and Fv/Fm reached the lowest point at 13：00 while Pn,Fv/Fm of all the treatments were significantly higher than those of CK but Gs was significantly lower than that of CK.Furthermore,the midday relative water content（RWC） of 5 000 μL·L-1 and 10 000 μL·L-1 treatments was significantly higher than that of CK.At 13：00,Pn,Gs and RWC of plants grown at RZ CO2 10 000 μL·L-1 were 1.39-0.81 and 1.27-folds of CK plants,respectively.Fresh and dry mass of shoot leaf and root in the 5 000 μL·L-1 and 10 000 μL·L-1 treatment were both significantly heavier than those of CK.The productivity of 2 500 μL·L-1 had no significant difference with CK.It was predicted that increasing RZ CO2 concentration could alleviate midday depression of photosynthesis and hence increase the productivity of aeroponic tomato.