学术
摘 要:
以砂培菊芋（Helianthus tuberosus）幼苗作为试验材料，分别进行不同浓度NaCl（50、100、150、200、250mmol·L^-1）和Na2CO3（25、50、75、100、125mmol·L^-1）胁迫处理，以1／2全营养液作为对照，处理7d后研究NaCl和Na2CO3胁迫处理对菊芋幼苗叶片光合作用及叶绿素动力学参数的影响。结果表明：1）在NaCl处理下，当浓度小于150mmol·L^-1时，增加了菊芋的叶绿素含量、净光合速率（Net photosynthetic rate，Pn）和气孔导度（Stomatal conductivity，Gs），对荧光参数PSⅡ的电子传递情况（Fm／Fo）、PSⅡ原初光能转换效率（Fv／Fm）、PSⅡ量子效率（Actual quantum yield of PSⅡ under actinic irradiation，ФPSⅡ）和光化学猝灭系数（Photochemical quenching coefficient，qP）和非光化学猝灭系数（Non-photochemical quenching coefficient，NPQ）没有显著影响，随着浓度的增加，各项生理指标与对照相比除了NPQ显著增加，其余均显著降低；2）在Na2CO3胁迫处理下，随着Na2CO3浓度的增加，与对照相比菊芋幼苗叶绿素含量、Pn、Gs以及叶绿素a荧光诱导动力学参数Fm／Fo、Fv／Fm、ФPSⅡ和qP均显著降低，NPQ显著增加；3）就NaCl和Na2CO3相比而言，在相同Na^＋浓度情况下，处于Na2CO3胁迫下的菊芋幼苗的叶绿素含量、Pn、Gs以及叶绿素a荧光诱导动力学参数Fm／Fo、Fv／Fm、ФPSⅡ和qP下降幅度和NPQ的增加幅度均显著大于NaCl，这说明NaCl和Na2CO3胁迫均对菊芋幼苗造成不同程度的伤害，但在相同Na^＋浓度情况下，Na2CO3的伤害程度大于NaCl。由此说明菊芋对盐的忍耐程度高于碱。[著者文摘]
文章出处:
《植物生态学报》-2008年32卷1期 -161-167页
栏目信息:
EFFECTS OF NaCl AND Na2CO3 STRESSES ON PHOTOSYNTHESIS AND PARAMETERS OF CHLOROPHYLL FLUORESCENCE IN HELIANTHUS TUBEROSUS SEEDLINGS
XUE Yan-Feng and LIU Zhao-Pu （ College of Resources and Environmental Science, Nanfing Agricultural University, Nanjing 210095, China）
Abstract:
Aims Our objective was to explore the effects of saline-alkali stress on photosynthetic apparatus of Helianthus tuberosus seedlings. Methods H. tuberosus seedlings were treated with NaCl （50, 100, 150, 200, 250 mmol·L^-1） and Na2CO3 （25, 50, 75, 100, 125 mmol·L^-1） in plastic pots with sand. Others were cultured in modulated halfstrength Hoagland solution as a control. We studied the effects of NaCl and Na2CO3 on net photosynthetic rate （Pn） and parameters of chlorophyll fluorescence by measuring chlorophyll content, Pn, stomatal conductivity （ Gs ） and fluorescence parameters after 7 days. Important findings Significant increases of chlorophyll content, Pn and Gs compared with the control were observed under the 150 mmol·L^-1 NaCl treatment, whereas there were no effects on fluorescence parameters, Fv/Fm（mayximal photochemical efficiency of photosystem Ⅱ（PSⅡ ） while all PSⅡ reaction centers are open）, Fm/Fo （another expression for the maximal photochemical efficiency of PSⅡ ）, ФPSⅡ （actual quantum yield of PSⅡ under actinic irradiation）, qP （ photochemical quenching coefficient）, and NPQ （ non-photochemical quenching coefficient）. But with greater NaCl concentration, the chlorophyll content, Pn, Gs and fluorescence parameters significantly decreased except for an increase of NPQ compared with the control. When H. tuberosus seedlings were treated with Na2CO3, chlorophyll content, Pn, Gs, Fv/Fm, Fm/Fo, ФPSⅡ and qP significantly decreased and NPQ increased compared with the control. At the same concentration of Na^＋ , the decrease of chlorophyll content, Pn, Gs, Fv/Fm, Fm/Fo, ФPSⅡ,qP and the increase of NPQ were higher in Na2CO3 stress than in NaCl stress. All results suggested that the tolerance of H. tuberosus seedlings to saline stress was higher than to alkaline stress.[著者文摘]
Key words:
NaCl, Na2CO3, Helianthus tuberosus, stress, photosynthesis, fluorescence
基金资助:
863海洋生物技术主题项目（2003AA627040）
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