《植物生理学报》 2021, 57(6): 1281-1290

低锌胁迫对湖北海棠平邑甜茶幼苗光合特性以及¹³C积累 和分配的影响

于波，秦嗣军，吕德国^*

沈阳农业大学园艺学院, 辽宁省果树品质发育与调控重点实验室, 沈阳110866

通信作者：吕德国；E-mail: lvdeguo@syau.edu.cn

摘　要：

以湖北海棠平邑甜茶(Malus hupehensis var. pingyiensis)砧木为试材, 采用砂培方式结合13C同位素示 踪技术, 研究了不同锌水平(Zn2+浓度分别为0.02、0.5、2.0、4.0 μmol·L−1)对幼苗叶片光合性能、荧光参 数以及13C积累与分配的影响。结果表明, 低锌(0.02、0.5和2.0 μmol·L−1 Zn2+)处理下幼苗各器官生物量、 净光合速率(Pn)和气孔导度(Gs)均较对照(4.0 μmol·L−1 Zn2+)处理明显降低。与对照相比, 低锌胁迫明显降 低了叶片光系统II (PSII)最大光化学效率(Fv/Fm)、PSII实际光化学效率(ΦPSII)以及PSII电子传递速率(ETR)。 低锌胁迫处理下的叶片核酮糖-1,5-二磷酸羧化酶(Rubisco)、蔗糖合酶(SS)与蔗糖磷酸合成酶(SPS)活性 随时间增长逐渐降低, 在处理35 d后达到最低水平。13C同位素示踪结果表明, 0.02、0.5和2.0 μmol·L−1 Zn2+处理下幼苗根系13C积累量在13C标记结束12 h后为0.03、0.05和0.16 mg·株−1, 较对照分别降低了 88.5%、80.8%和38.5%。13C标记结束72 h后, 低锌处理下叶片13C分配率较对照提高了18.5%、12.2%和9.0%,  而根系13C分配率较对照降低了47.1%、35.4%和26.0%。以上结果表明, 低锌胁迫降低了叶片Pn, 削弱了 叶片碳同化能力, 阻碍了叶片光合同化物的合成及其向根系的运输, 进而抑制了根系生长。

关键词： Malus; zinc deficiency; photosynthesis; fluorescence; 13C; accumulation; distributio

资助：国家重点研发计划项目(2016YFD0201115)、国家现代苹果产业技术体系建设项目(CARS-27)和国家自然科学基金(31972359)

Effects of zinc deficiency stress on photosynthetic characteristics and  ¹³C accumulation and distribution of Malus hupehensis var. pingyiensis seedlings

YU Bo, QIN Sijun, LÜ Deguo^*

College of Horticulture, Shenyang Agricultural University, Liaoning Province Key Laboratory of Fruit Quality Development and Regulation, Shenyang 110866, China

Corresponding author: LÜ Deguo; E-mail: lvdeguo@syau.edu.cn

Abstract:

Malus hupehensis var. pingyiensis seedlings, as test materials, were cultured in sand. The chlorophyll fluorescence analysis and track technology of 13C were used to study the effects of different zinc levels (0.02, 0.5, 2.0 and 4.0 μmol·L−1) on photosynthetic physiological characteristics, chlorophyll fluorescence characteristics and 13C photosynthate accumulation of seedlings. The results show that, compared  with the control (4.0 μmol·L−1 Zn2+), the biomass, net photosynthetic rate (Pn) and stomatal conductance  (Gs) of the seedlings under zinc deficiency (0.02, 0.5 and 2.0 μmol·L−1 Zn2+) treatment were significantly decreased. The photosystem II (PSII) actual photochemical efficiency (ΦPSII), PSII electron transport rate (ETR) and PSII maximum photochemical efficiency (Fv/Fm) in leaves of M. hupehensis var. pingyiensis seedlings dropped significantly under zinc deficiency stress. As the treatment time of the experiment increased,  the activities of ribulose-1,5-diphosphate carboxylase (Rubisco), sucrose synthase (SS) and sucrose phosphatase (SPS) decreased gradually under zinc deficiency stress, and reached the lowest level after 35  days. The results of 13C tracer test showed that, after 12 h of the end of 13C labeling, the 13C accumulation  of roots under the treatment of 0.02, 0.5 and 2.0 μmol·L−1 Zn2+ were 0.03, 0.05 and 0.16 mg·plant−1, which  was 88.5%, 80.85% and 38.5% lower than the control, respectively. After 72 h of the end of 13C labeling, the  13C distribution of leaves under zinc deficiency treatment (0.02, 0.5 and 2.0 μmol·L−1 Zn2+) was 18.7%,  12.4% and 9.0% higher than that of the control, while the 13C distribution of roots was decreased by 47.1%,  35.4% and 26.0%, respectively, compared to the control. Our results indicate that zinc deficiency stress reduces the net photosynthetic rate of leaves, weakens the carbon assimilation capacity of leaves, hinders  the synthesis of photosynthates in leaves and their transportation to roots, and thus inhibits the growth of  roots.

Key words: 苹果属; 低锌; 光合; 荧光; 13C; 积累; 分配