铝胁迫对蓼科植物生长和光合、蒸腾特性的影响

Effects of aluminum stress on growth and characters of photosynthesis and transpiration in polygonaceae plants

关键词:  铝胁迫  蓼科植物  光合  蒸腾  叶绿素荧光

Key words:  aluminum stress  polygonaceae plants  photosynthesis  transpiration  chlorophyll fluorescence characteristics

摘要:

采用水培试验,设置5种铝处理浓度,研究了铝对3种蓼科植物酸模叶蓼、杠板归和辣蓼叶片光合、蒸腾和叶绿素荧光参数的影响。结果表明,高铝处理(400 μmol·L^-1)显著抑制3种蓼科植物地上部和根系生长,并且导致3种蓼科植物叶片叶绿素含量、Chla/Chlb、净光合速率(Pn)、水分利用效率(WUE)、PSII光合电子传递量子效率(φ_PSII)和光化学猝灭系数(qP)显著下降。中低铝处理(25～100 μmol·L^-1)时,与对照相比,酸模叶蓼生物量显著增加,杠板归显著减少,辣蓼先增加后减少。其中,酸模叶蓼和辣蓼叶绿素含量、Chla/Chlb、Pn、蒸腾速率(Tr)、胞间CO₂浓度(Ci)、PSII最大光化学效率(Fv/Fm)、qP均未发生显著变化,但辣蓼WUE、φPSII和非光化学猝灭系数(NPQ)显著下降,酸模叶蓼无显著变化; 而杠板归除Ci、Fv/Fm外,其余叶片光合、蒸腾及叶绿素荧光参数均出现显著下降。上述结果表明,酸模叶蓼在中低铝处理条件下可通过保持较高的叶绿素含量、Chla/Chlb、WUE、Pn、PSII反应中心光化学反应效率以及提高非辐射能量耗散来增强其对铝的耐性。

Abstract:

Three polygonaceae plants(Polygonum lapathifolium,P.perfoliatum and P.hydropiper)were used to study the effects of five aluminum(Al)concentrations(0,25,50,100,400 μmol·L^-1)on leaf photosynthesis,transpiration and chlorophyll fluorescence characteristics with the solution culture method. The results showed that the high Al treatment(400 μmol·L^-1)significantly decreased the growth of aboveground and root system,the leaf chlorophyll content,Chla/Chlb,net photosynthetic rate(Pn),water use efficiency(WUE),quantum yield of electron transport at PSII(φPSII)and coefficient of photochemical quenching(qP)of three polygonaceae plants. In the low and medium concentrations of Al treatments(25～100 μmol·L^-1),the biomass was significantly promoted in P.lapathifolium,significantly reduced in P.perfoliatum,promoted firstly and then reduced again in P.hydropiper compared to the control. Meanwhile,the chlorophyll content,Chla/Chlb,Pn,transpiration rate(Tr),intercellular CO₂ concentration(Ci),maximal photochemical efficiency(Fv/Fm)and qP were not significantly changed in P.lapathifolium and P.hydropiper,but WUE,φPSII and coefficient of photochemical non-quenching(NPQ)were significantly decreased in P.hydropiper only. However,in P.perfoliatum,leaf photosynthesis,transpiration and chlorophyll fluorescence characteristics other than Ci,Fv/Fm,were decreased remarkably. These results indicated that P.lapathifolium could enhance the tolerance to Al stress under low and medium Al treatments by maintaining steady chlorophyll content,Chla/Chlb,WUE,Pn,photochemical reaction efficiency at PSII and increasing non-radiative dissipation of absorbed excitation energy through NPQ.