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• Flexor cells expand, extensor cells contract, influencing vacuoles. • Hormone levels (IAA, IPA, ZR, BR) differ in flexor and extensor cells. • Exogenous IAA (50–100 μM) aids nyctinastic movement leaflet unfolding. • "Light-circadian rhythm-hormone-ion channel" regulatory pathway. Averrhoa carambola , a commonly cultivated tree, exhibits leaflet nyctinastic movement. However, the underlying mechanism remains unclear. The pulvinus, as a motor organ, coordinates the motion of its attached leaflet. During the leaflet expansion, flexor cells shift from contraction to expansion, with concurrent expansion and fusion of vacuole. In contrast, the extensor cells move from expansion to contraction, causing vacuole contraction and increased vacuole numbers. During the process of leaflet expansion and closure, the contents of IAA and IPA in flexor muscles increased significantly, but did not show significant changes in extensor muscles, BR content showed an opposite trend in extensor and flexor muscles, and the content of ZR increased significantly in extensor muscles but decreased significantly in flexor muscles, and ZR content only decreased in extensor muscles, but did not show significant changes in flexor muscles. Exogenous IAA (50–100 μM) significantly aids in leaflet unfolding during night time. Transcriptome analysis reveals gene enrichment in circadian rhythms, hormone signaling, ion channels, and other pathways during leaflet opening and closure. The expression of AcaCRY3, AcaPHOT1–1, AcaAPRR2, AcaLHY , and AcaAKT1–1 is prominent during expansion, while AcaAUX22–1 stands out during closure. These findings suggest a potential regulatory pathway in A. carambola 'Daguo Tianyangtao 2′ leaflets, involving light, circadian rhythm, hormone signaling, and ion channels. Findings of this study can do a great deal to broaden the plant nyctinastic movement research. [ABSTRACT FROM AUTHOR]

The genus Oxalis contains important species worldwide with great economic and edible values. However, the testing guidelines have not been furbished, especially in China. Oxalis germplasm, including 60 species and 125 varieties, was collected from home and abroad and extensive field trials and phenotypic observations were conducted along with quantitative taxonomy, observations, correlation analysis and cluster analysis. Under the test guidelines of the International Union for the Protection of New Plant Varieties (UPOV), general guidelines for testing for distinctness, uniformity, stability (DUS) of new plant varieties, and Japanese test guidelines for DUS of Oxalis , 96 test characteristics (38 qualitative characteristics, 28 quantitative characteristics and 30 pseudo-qualitative characteristics) were determined as DUS test characteristics of Oxalis. Each test characteristic was scientifically graded and accurately described, and standard varieties and characteristic diagrams were provided for some characteristics. The guidelines for testing DUS of new plant varieties of Oxalis provide a standard for examining and testing new varieties of plants. [ABSTRACT FROM AUTHOR]