外源SiNPs对盐胁迫下生姜幼苗生长和生理特性的影响

Effects of exogenous SiNPs on growth and physiological characteristics of ginger seedlings under salt stres

【目的】研究外源二氧化硅纳米颗粒(SiNPs)对盐胁迫下生姜幼苗生长和生理特性的影响,为SiNPs在生姜抗盐性中的应用提供理论依据与技术支撑。【方法】以竹根姜(Zingiber officinale Roscoe.cv.zhugen)盆栽苗为试材,设置用100 mg/L SiNPs溶液喷施全株5 d后再用蒸馏水浇灌植株根部的SiNP100处理、用蒸馏水喷施全株5 d后再用20 g/L NaCl溶液浇灌植株根部的NaCl处理以及用100 mg/L SiNPs溶液喷施全株5 d后再用20 g/L NaCl溶液浇灌植株根部的SiNP100+NaCl处理,以前后均用蒸馏水处理为对照(CK)。随机选取不同处理后的生姜幼苗,观测其生长形态、光合色素(叶绿素a(Chl a)、叶绿素b(Chl b)、叶绿素a+b(Chl(a+b))和类胡萝卜素(Car))含量、叶绿素荧光参数(最大光化学效率(F_(v)/F_(m))、实际光量子效率(ΦPSⅡ)、光化学淬灭系数(qP)和非光化学淬灭系数(NPQ))、光合作用参数(净光合速率(P_(n))、蒸腾速率(T_(r))和气孔导度(G_(s)))、丙二醛(MDA)和H_(2)O_(2)含量以及抗氧化酶(超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT))活性。【结果】与CK相比,SiNP100处理生姜幼苗的根尖数显著增加,Chl a、Chl b和Chl(a+b)含量显著提高,NPQ显著下降,T_(r)显著增加,SOD和CAT活性显著升高,MDA和H_(2)O_(2)含量显著降低,其余指标均与CK差异不显著。在NaCl胁迫条件下,生姜幼苗根系生长受到抑制,叶片明显变黄,与CK相比,总根长、根系表面积、根尖数显著减少,4种光合色素含量均显著下降,F_(v)/F_(m)、ΦPSⅡ和qP显著降低,而NPQ显著升高,P_(n)、T_(r)和G_(s)显著降低,SOD、POD和CAT活性以及MDA和H_(2)O_(2)含量均显著升高。SiNP100预处理则可以缓解NaCl胁迫对生姜幼苗的损伤,总根长、根系表面积、根尖数较NaCl处理显著增加,叶片发黄症状也得到缓解;此外,与NaCl处理相比,SiNP100+NaCl处理生姜幼苗的Chl a、Chl b、Chl(a+b)含量和F_(v)/F_(m)、ΦPSⅡ、qP、P_(n)、T_(r)以及SOD、POD、CAT活性显著提高,而NPQ和MDA、H_(2)O_(2)含量显著下降,Car含量和G_(s)则与NaCl处理差异不显著。【结论】外源SiNPs预处理能通过促进植株根系生长、增加光合色素含量、提高光合作用效率、调节抗氧化酶活性、降低MDA和H_(2)O_(2)含量来缓解盐胁迫对生姜幼苗造成的生长抑制和氧化损伤,从而增强生姜植株的抗盐性。

【Objective】This study investigated the effects of exogenous silica nanoparticles(SiNPs)on growth and physiological characteristics of ginger seedlings under salt stress to provide reference and sup-port for using SiNPs in salt resistance of ginger.【Method】The Zhugen ginger(Zingiber officinale Ros-coe.cv.zhugen)plants in pots were sprayed with 100 mg/L SiNPs for 5 days and irrigated with distilled water on roots(the SiNP100 treatment).In the NaCl treatment,whole plants were sprayed with distilled water for 5 days and then irrigated with 20 g/L NaCl on roots.In the SiNP100+NaCl treatment,whole plants were sprayed with 100 mg/L SiNPs for 5 days and then irrigated with 20 g/L NaCl on roots.Dis-tilled water treatment was used as control(CK).The growth morphology,photosynthetic pigment con-tents(chlorophyll a,chlorophyll b,chlorophyll(a+b)and carotenoids),chlorophyll fluorescence parame-ters(maximum photochemical yield(F_(v)/F_(m)),actual photochemical quantum yield(ΦPSⅡ),photochemi-cal quenching coefficient(qP)and non-photochemical quenching coefficient(NPQ)),photosynthetic pa-rameters(net photosynthetic rate(P_(n)),transpiration rate(T_(r))and stomatal conductance(G_(s))),malon-dialdehyde(MDA)and H_(2)O_(2) contents,and antioxidant enzyme activities(superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT))of ginger seedlings were observed and measured under different treatments.【Result】Compared with CK,SiNP100-treated ginger seedlings showed significant increases in root tip number,contents of Chl a,Chl b and Chl(a+b),T_(r) and SOD and CAT activities,significant de-creases in NPQ and contents of MDA and H_(2)O_(2),while no significant changes in other indicators.Under salt stress,root growth of ginger seedlings was inhibited,leaves turned yellow,and total root length,root surface area and root tip number were significantly decreased compared with CK.Photosynthetic pigment contents,F_(v)/F_(m),ΦPSⅡ,qP and P_(n),T_(r),G_(s) were significantly decreased,but NPQ,activities of SOD,POD and CAT as well as contents of MDA and H_(2)O_(2) were significantly increased.SiNP100 pretreatment allevia-ted the damages caused by salt stress,and total root length,root surface area and root tip number were sig-nificantly increased compared with NaCl treatment,and leaf yellowing symptom was also alleviated.In ad-dition,Chl a,Chl b and Chl(a+b)contents,F_(v)/F_(m),ΦPSⅡ,qP,P_(n),T_(r),G_(s) and activities of SOD,POD,and CAT in ginger seedlings treated with SiNP100+NaCl were significantly increased,NPQ,MDA and H_(2)O_(2) contents were significantly decreased,while Car and G_(s) were not significantly changed,in comparison with the NaCl treatment.【Conclusion】Exogenous SiNPs pretreatment promoted root growth,photosyn-thetic pigment contents and photosynthetic efficiency,regulated activities of antioxidant enzyme and re-duced MDA and H_(2)O_(2) contents,so as to alleviate growth inhibition and oxidative damage caused by salt stress and enhance the salt resistance of ginger plants.