《植物生理学报》 2021, 57(1): 139-148

主根长度对辽东栎幼苗形态和光合作用的影响

韩丽君，周帅^*，郝向春

山西省林业和草原科学研究院, 太原030012

通信作者：周帅；E-mail: 505239941@qq.com

摘　要：

苗期断根是辽东栎育苗的常用技术, 准确预测主根长度对该项技术的实施至关重要。本研究采用不同主根长度的辽东栎幼苗为试材, 对地上部分形态、叶绿素含量、叶绿素荧光、光合作用、生物量等指标进行方差分析(ANOVA)、相关分析和回归分析。方差分析表明, 株高、地径、总叶面积、相对叶绿素含量(SPAD)和根生物量分配比随主根长度增加而增加; 当主根长度超过40 cm时, PSII单位反应中心用于热耗散的能量和用于非光化学淬灭的能量均降低, SPAD、PSII单位面积有活性反应中心的数量(RC/CS₀)、叶片总性能指数(PI_total)、光照条件下PSII运行效率(QY')、最大净光合速率(A_max)均提高; 当主根长度超过60 cm时, 株高、地径、根生物量、茎生物量和单株生物量显著增加。关联分析表明, 主根长度与单株生物量、叶生物量、根生物量、总叶面积密切相关; 主根长度通过总叶面积、叶生物量和单株生物量, 与SPAD、QY'、A_max等参数形成关联, 并通过SPAD和QY'进一步与RC/CS₀、PI_total等快速叶绿素荧光参数建立联系。回归分析表明, 基于地径、PSII单位反应中心捕获的能量(TR₀/RC)、单位反应中心吸收的能量(ABS/RC)建立的主根长度预测模型拟合效果好, 预测值与实测值无显著差异, 主根长度平均预测误差值为7.0 cm。辽东栎幼苗的主根长度对植株形态和光合生理有显著影响, 可以通过ABS/RC、TR₀/RC和地径等参数进行快速、无损的预测。

关键词：辽东栎; 断根; 叶绿素荧光; 光合作用; 生物量

收稿：2020-08-20   修定：2020-11-24

资助：国家重点研发计划(2017YFD0600602)

Effect of taproot length on morphology and photosynthesis of Liaodong oak seedlings

HAN Lijun, ZHOU Shuai^*, HAO Xiangchun

Shanxi Academy of Forestry and Grassland Sciences, Taiyuan 030012, China

Corresponding author: ZHOU Shuai; E-mail: 505239941@qq.com

Abstract:

Root pruning at seedling stage is a general technique for Liaodong oak (Quercus liaotungensis) seedling nursery, and accurate prediction of taproot length is crucial for the implementation of this technique. The aboveground morphology, chlorophyll content, chlorophyll fluorescence, photosynthesis, and biomass were analyzed by ANOVA, correlation analysis, and regression analysis using Q. liaotungensis seedlings with different taproot lengths as test material. ANOVA showed that plant height, ground diameter, total leaf area, relative chlorophyll content (SPAD), and root biomass allocation ratio increased with taproot length. When the taproot length exceeded 40 cm, the quantum yield of energy dissipation in PSII antenna and non-photochemical quenching decreased, while SPAD, the ratio of the total number of active PSII reaction centers (RC/CS₀), total performance index on absorption basis (PI_total), steady-state PSII quantum yield in light (QY') and maximum net photosynthetic rate (A_max) were all increased. When the taproot length exceeded 60 cm, plant height, ground diameter, root biomass, stem biomass, and individual biomass increased significantly. Correlation analysis showed that taproot length was strongly correlated with individual biomass, leaf biomass, root biomass, and total leaf area. Taproot length formed associations with SPAD, QY', and A_max through total leaf area, leaf biomass, and individual biomass, and further correlated with fast chlorophyll fluorescence parameters such as RC/CS₀ and PItotal through SPAD and QY'. Regression analysis showed that the taproot length prediction model based on ground diameter, trapped energy flux per reaction center (TR₀/RC), and absorption flux per reaction center (ABS/RC) with better accurace, with no significant difference between predicted and measured values, and the average predicting error value was 7.0 cm. The taproot length of Q. liaotungensis seedlings has a significant effect on plant morphology and photosynthetic physiology, and can be rapidly and nondestructively predicted by ABS/RC, TR₀/RC, and ground diameter.

Key words: Quercus liaotungensis; root pruning; chlorophyll fluorescence; photosynthesis; biomass