外源茉莉酸甲酯调控芍药切花‘公爵夫人’瓶插品质及生理效应

李小康; 王警琨; 高博文; 管赢; 符真珠; 袁欣; 刘艺平; 贺丹

外源茉莉酸甲酯调控芍药切花‘公爵夫人’瓶插品质及生理效应

Effects of Methyl Jasmonate Application on Quality and Physiology of Cut Peony Flowers in Vase

摘要

摘要:
目的探究外源茉莉酸甲酯（methyl jasmonate, MeJA）对芍药切花衰老进程及挥发物品质的调控机制，为MeJA在芍药切花保鲜与挥发物品质协同调控提供理论依据。
方法以芍药品种‘公爵夫人’（Paeonia lactiflora ‘Duchesse de Nemours’）为切花材料，清水为对照（CK），设置基础保鲜液中添加0、5、10和20 μmol·L⁻¹ MeJA处理。瓶插期间测定花径、鲜样质量、相对鲜样质量变化、花瓣明度（L*）及总色差（ΔE*）等瓶插品质指标；测定超氧化物歧化酶（superoxide dismutase, SOD）、过氧化物酶（peroxidase, POD）活性、丙二醛（malondialdehyde, MDA）和可溶性蛋白质含量及乙烯释放速率；采用顶空固相微萃取-气相色谱-质谱联用技术（headspace solid-phase microextraction-gas chromatography-mass spectrometry, HS-SPME-GC-MS）分析瓶插第4 d花瓣挥发性化合物；采用实时荧光定量PCR（real-time quantitative polymerase chain reaction, RT-qPCR）检测香气合成相关基因PlTPS6、PlTPS2及乙烯生物合成关键基因PlACS（GenBank登录号：JX512359）和PlACO（GenBank登录号：JN132109）的相对表达水平。
结果 10 μmol·L⁻¹ MeJA处理显著提升了芍药切花的瓶插品质。在抗氧化防御方面，10 μmol·L⁻¹ MeJA显著提高瓶插中前期SOD与POD活性，降低MDA积累（P＜0.05），有效维持花瓣细胞膜完整性；在乙烯代谢上，MeJA与乙烯释放速率之间呈浓度依赖效应，其中10 μmol·L⁻¹处理显著抑制乙烯释放并下调 PlACS、PlACO 的表达。不同浓度MeJA处理对芍药切花挥发性化合物的组成及相对峰面积比产生了差异化影响，10 μmol·L⁻¹ MeJA还能提高萜类及α-甲基苯甲醇等关键挥发物相对含量，并上调PlTPS6、PlTPS2表达量。
结论外源 MeJA 处理可调控芍药切花瓶插期的衰老进程与挥发物代谢，其中，10 μmol·L⁻¹ MeJA处理在延缓切花衰老、维持瓶插品质及调控香气合成相关基因表达方面表现出较好的综合效果；不同浓度MeJA对挥发性化合物组成的调控效应存在差异。

Abstract:
Objective Effects of methyl jasmonate (MeJA) application on the senescence and fragrance of cut peony flowers in vase were evaluated.
Method Cut flowers of Paeonia lactiflora Duchesse de Nemours were placed in vases with distilled water (CK), a basal solution added with 0, 5, 10, or 20 μmol·L⁻¹ of MeJA. Flower diameter, fresh mass, relative fresh mass change, petal lightness (L*), and total color difference (ΔE*) were measured. Superoxide dismutase (SOD) and peroxidase (POD) activities as well as malondialdehyde (MDA) and soluble protein contents and ethylene production rate of the cut flowers were determined. Volatiles in the petals on day 4 after start of experimentation were analyzed by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). RT-qPCR was used to determine expressions of the genes related to aromatics biosynthesis, PlTPS6 and PlTPS2, as well as the key ethylene-biosynthesis genes, PlACS (GenBank accession no. JX512359) and PlACO (GenBank accession no. JN132109).
Results Presence of 10 μmol·L⁻¹ MeJA in the vase water significantly improved the quality of cut flowers. The SOD and POD activities were significantly raised and MDA accumulation reduced in early to middle stages (P＜0.05), while the initial petal cell membrane integrity largely maintained. The effect of MeJA addition on floral ethylene metabolism was concentration dependent. At 10 μmol·L⁻¹, it significantly inhibited ethylene production and downregulated the expressions of PlACS and PlACO. Varied concentrations also affected differently in the composition and volatile relative peak-area ratio. For instance, the MeJA application at 10 μmol·L⁻¹ elevated the relative contents of key volatiles, such as terpenoids and α-methylbenzyl alcohol, and upregulated the expressions of PlTPS6 and PlTPS2.
Conclusion Adding MeJA in vase water could alter the senescence and volatile metabolism of cut peonies. Among the tested concentrations, 10 μmol·L⁻¹ MeJA showed outstanding benefits on the cut flowers in delaying aging, preserving ornamental quality, and positively regulating expressions of the genes related to aromatics biosynthesis.

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