3个桃砧木品种对淹水的光合生理响应特征

Photosynthetic Characteristics Response to Water-logging in 3 Peach Rootstock Seedlings

以生产中常用的3个桃砧木品种毛桃、山桃和列玛格幼苗为试材,以正常供水为对照,采用模拟水涝试验研究了淹水对其光合特性的影响,探讨桃砧木耐涝的光合机理。结果显示:淹水胁迫下,3个桃砧木叶片净光合速率(Pn)、相对含水量(RWC)、水分利用效率(WUE)、蒸腾速率(Tr)、气孔导度(Gs)、表观量子效率(AQY)、羧化效率(CE)和最大电子传递速率(Jmax)等均显著低于对照,而丙二醛(MDA)含量显著高于对照。试验后期,淹水胁迫下列玛格叶片的叶绿素含量增加显著高于毛桃和山桃,MDA含量显著低于毛桃和山桃,且Pn、RWC、Tr、WUE和Gs下降幅度最小,光合能力最强,而毛桃次之,山桃下降幅度最大;3个桃品种的耐涝性表现为列玛格>毛桃>山桃。研究表明,淹水使桃砧木叶片膜脂过氧化加剧,气孔开度减小,水分代谢机能降低,光合电子传递和光合碳同化能力下降,光合机构受损,光合作用效率降低;而列玛格品种在淹水胁迫下叶绿素合成加强,叶片RWC下降缓慢,光能吸收、传递和水分代谢能力以及抗光抑制和光氧化能力最强,膜脂过氧化程度最轻,从而保持最高的光合能力。

To study the photosynthetic mechanism of submergence resistance in peach rootstocks,we studied the effects of water-logging on photosynthetic characteristics of peach rootstock seedlings [Maotao（Prunus persica（L.） Batsch.）,Shantao（P.davidiana（Carr.） Franch.）] and Nemaguard with normal water supply as control.The results showed that net photosynthetic rate（Pn）,relative water content（RWC）,water use efficiency（WUE）,transpiration rate（Tr）,stomatal conductance（Gs）,apparent quantum yield（AQY）,carboxylation efficiency（CE） and maximal photosynthetic electron transport rate（Jmax） in leaves were significantly lower than control,but the MDA content was opposite.Nemaguard had higher chlorophyll content under submergence stress in the late experiment period.Meanwhile,decrease amplitude of Pn,RWC,Tr,WUE and Gs of Nemaguard were the lowest among the 3 cultivars,Maotao took second place.The level of water-logging tolerance among the 3 peach rootstock seedlings was NemaguardMaotaoShantao.As response to water-logging,membrane-lipid peroxidation was intensified,the stomatal aperture,water metabolism capacity,photosynthetic electron transport rate and photosynthetic capacity decreased.The chlorophyll biosynthesis of Nemaguard under water-logging enhanced and descending speed of RWC were slower,which led to higher light absorption and water metabolism capacity;Nemaguard had stronger resistance to photoinhibition and photooxidation because of the lowest membrane lipid peroxide level,there for,Nemaguard could keep the highest photosynthetic capacity among the 3 peach rootstock seedlings.