不同干旱胁迫条件下丛枝菌根真菌对木棉叶绿素荧光参数的影响

Effect of arbuscular mycorrhizal fungi on chlorophyll fluorescence parameters of Bombax ceiba under different drought stress conditions

为了探明丛枝菌根真菌(AMF)与木棉(Bombax ceiba Linn.)抗旱性的关系,采用盆栽法对不同干旱胁迫条件下接菌组(1 g土壤含100个AMF孢子)和未接菌组木棉叶绿素荧光参数进行了比较分析。结果表明:中度干旱胁迫(土壤相对含水量45%~50%)和重度干旱胁迫(土壤相对含水量30%~35%)条件下接菌组的初始荧光(F_o)均低于未接菌组;与对照(土壤相对含水量65%~70%)相比,重度干旱胁迫5、15和35 d,接菌组的F_o值分别升高了10.39%、20.93%和14.14%,未接菌组的F_o值分别升高了26.95%、48.75%和71.35%。接菌组的PSⅡ最大光化学效率(F_v/Fm)和PSⅡ潜在活性(F_v/F_o)在中度和重度干旱胁迫5、15和35 d均高于未接菌组。与对照相比,重度干旱胁迫5、15和35 d,接菌组的F_v/Fm值分别降低了9.09%、6.85%和22.06%,未接菌组的F_v/Fm值分别降低了10.67%、16.21%和52.78%;接菌组的F_v/F_o值分别降低了28.14%、22.43%和46.01%,未接菌组的F_v/F_o值分别降低了28.38%、48.20%和75.96%。总体来看,在中度和重度干旱胁迫条件下,接菌组的PSⅡ实际光量子产量[Y(Ⅱ)]、PSⅡ非调节性能量耗散的量子产量[Y(NO)]、光化学淬灭系数(qP)和光合电子传递速率(ETR)高于对照,而PSⅡ调节性能量耗散的量子产量[Y(NPQ)]和非光化学淬灭系数(qN)低于对照;未接菌组的Y(Ⅱ)、qP、qN和ETR值低于对照,而Y(NO)和Y(NPQ)值则高于对照。研究结果显示:AMF能够减轻干旱尤其是重度干旱胁迫条件下木棉受伤害和光抑制的程度,并提高其叶片PSⅡ反应中心的活性,从而增强木棉在干旱胁迫条件下的生存能力。

To figure out the relationship between arbuscular mycorrhizal fungi （ AMF） and drought resistance of Bombax ceiba Linn.,chlorophyll fluorescence parameters of B. ceiba of inoculation （ 1 g soil containing 100 spores of AMF） and non-inoculation groups under different drought stress conditions were compared and analyzed by using pot-culture method. The results show that initial fluorescence （ Fo ） of inoculation group is lower than that of non-inoculation group under moderate drought stress （ soil relative water content of 45% - 50%） and severe drought stress （soil relative water content of 30% - 3 5 % ） conditions. Compared with the control （soil relative water content of 6 5 % - 7 0 % ）, at severe drought stress for 5,15,and 35 d,_ Fo value of inoculation group increases by 10. 3 9 %,20. 93% , and 14. 1 4 %, respectively, that of non-inoculation group increases by 26. 9 5 %,48. IS% , and 71. 3 5 %, respectively. The maximum photochemical efficiency of PS H （ Fv /F m ） and potential activity of PSH （Fv/F.） of inoculation group are higher than those of non-inoculation group at moderate and severe drought stresses for 5, 15,and 35 d. Compared with the control,at severe drought stress for 5, 15, and 35 d, Fv /Fm value of inoculation group decreases by 9. 0 9 %,6. 85% ,and 22. 0 6 %, respectively, and that of non-inoculation group decreases by 10.6 7 %, 16.2 1 %, and 52. 7 8 %, respectively; Fv /Fo value of inoculation group decreases by 28. 1 4 %, 22. 4 3 %, and 46. 0 1 %, respectively, and that of non-inoculation group decreases by 28. 3 8 %, 48. 2 0 %, and 75. 9 6 %, respectively. In general, under moderate and severe drought stress conditions,effective quantum yield of PS H 〔 F（ H ） ] , quantum yield of non-regulated energy dissipation of PS H 〔 F（NO）〕 ,photochemical quenching coefficient （ qP） , and photosynthetic electron transport rate （ ETR） of inoculation group are higher than those of the control, while quantum yield of regulated energy dissipation of PS H 〔 Y （ NPQ ）〕 and non-photochemical quenching coefficient （qW） are lower than those of the control; F（ H ）, qP, qW, and ETR values of non-inoculation group are lower than those of the control, while F（NO） and Y（NPQ） values are higher than those of the control. It is suggested that AMF can reduce the damage and photoinhibition degrees of B. ceiba under drought stress （especially severe drought stress） condition and improve the activity of PSH reaction center of leaf,thus enhance the survivability of B. ceiba under drought stress condition.