LAUSR

PREMISE Spatial and temporal resource allocations within inflorescences have been well-studied in many plants based on flowering sequence or floral position. However, there had been few attempts to investigate architectural effects and resource competition in species where the blooming pattern does not follow a linear positional pattern within the inflorescence. Moreover, most flowering plants show female-biased sex allocation in early or basal flowers, but it is unclear in species with inherent and changeless ovule production. METHODS We investigated intra-inflorescence variation in reproductive traits of Salvia przewalskii, a perennial herb with 4-ouvle ovary flowers and flowering sequence-floral position decoupled inflorescences. To detect the effects of resource competition and architectural effects on reproductive success, we manipulated inflorescence (removal floral buds by position and flowering sequence) and pollination (opened and supplementary pollination). RESULTS Pollen production and dry mass deceased from bottom to top flowers but didn't significantly differ following flowering sequence, resulting in male-biased sex allocation in basal flowers. The seed production, fruit set, bud developmental exhibited significant declining trends from proximal to distal positions regardless of the thinning and pollen treatments. Meanwhile, the seed production, fruit set, bud developmental success did not significant difference when thinning conducted according to flowering sequence. CONCLUSIONS Architectural effects plays a crucial role in resource allocation within decoupled flowering inflorescences. Moreover, our results highlighted that inherent floral traits, such as changeless ovule production, may modify architectural effects on sex allocation. This article is protected by copyright. All rights reserved.