杨为海 向沛锦 陆超忠

摘  要：为揭示饥饿胁迫下澳洲坚果果实脱落与能量代谢的关系，以‘H2’澳洲坚果为试材，在果实发育早期对结果母枝进行环剥+去叶处理，定期测定果柄及果实不同组织中能量物质（ATP、ADP与AMP）含量、能荷（EC）水平和能量代谢关键酶（H+-ATPase与Ca2+-ATPase）活性的变化。结果表明：与对照相比，环剥+去叶处理明显促进了澳洲坚果早期果实脱落。自处理起至果实开始剧烈脱落时（处理后0～3 d），果皮的AMP与ADP、种子的ATP与ADP以及果柄的ATP、ADP与AMP含量均显著增加，果皮与种子的H+-ATPase以及果柄的H+-ATPase和Ca2+-ATPase活性明显增强，果柄与种子的EC水平显著升高，但果皮的EC值明显下降。在处理后期（处理后4～5 d），随着果实脱落加剧，果柄的Ca2+-ATPase以及果皮与种子的H+-ATPase及Ca2+-ATPase活性均显著增加，果柄和果皮的ATP以及果皮与种子的AMP含量均明显升高，而EC水平仅在果柄中显著提高。这些结果说明，饥饿胁迫可能通过影响澳洲坚果果柄及果实的能量代谢特性来影响早期果实脱落。

关键词：澳洲坚果;饥饿胁迫;能量代谢;果实;果柄

中图分类号：Q945      文献标识码：A

Abstract： In order to explore the relationship of fruit abscission with energy metabolism in macadamia under starvation stress， a treatment of girdling plus defoliation was made on the bearing shoots of macadamia cultivar ‘H2’ at the early stage of fruit development， and the changes in the energy contents （ATP， ADP and AMP）， energy charge （EC） levels， and the activity of key enzymes related to energy metabolism （H+-ATPase and Ca2+-ATPase） in the carpopodium and the different fruit tissues were investigated regularly. The results showed that a severe fruitlet drop occurred under the starvation stress induced by girdling plus defoliation treatment. From the beginning of treatment to the starting of severe fruit shedding （0–3 d after treatment）， the contents of AMP and ADP in pericarp， ATP and ADP in seed and fruit stalk increased significantly， the activity of H+-ATPase in pericarp and seed and the capacity of H+-ATPase and Ca2+-ATPase in carpopodium were significantly enhanced， and the EC level of carpopodium and seed was elevated obviously， but the EC value of pericarp decreased significantly. With the intensification of fruit abscission at the later stage of treatment （4–5 d after treatment）， the significantly increased activity in the Ca2+-ATPase of carpopodium and the H+-ATPase and Ca2+-ATPase of pericarp and seed occurred， and the content of ATP in carpopodium and pericarp and the level of AMP in pericarp and seed were obviously raised， while the EC level was significantly increased only in carpopodium. The results suggested that starvation stress might affect early fruit abscission by influencing the energy metabolism characteristics of macadamia pedicel and fruit.

Keywords： Macadamia; starvation stress; energy metabolism; fruit; carpopodium

DOI： 10.3969/j.issn.1000-2561.2021.11.022

澳洲堅果（Macadamia integrifolia，M. te-traphylla）是我国南亚热带地区新兴的常绿乔木果树，因其果实营养丰富且经济价值高而被广泛栽培。目前，澳洲坚果已在我国云南、广西、广东、贵州等省（区）推广种植约20万 hm2，成为热区精准扶贫及乡村振兴的特色产业。然而，澳洲坚果在果实发育早期发生严重落果，导致产量较低，已成为澳洲坚果栽培上亟需解决的重大难题。因此，探讨澳洲坚果幼果脱落机制，为生产上减轻澳洲坚果落果具有重要意义。……