Architectural effects regulate resource allocation within the inflorescences with nonlinear blooming patterns

Area of Science:

• Plant reproductive biology
• Ecology
• Evolutionary botany

Background:

• Intra-inflorescence resource allocation is key to plant reproductive success.
• Decoupled flowering patterns challenge traditional models of resource distribution.
• Understanding sex allocation in species with fixed ovule numbers is crucial.

Purpose of the Study:

• Investigate intra-inflorescence variation in reproductive traits of Salvia przewalskii.
• Determine the effects of resource competition and inflorescence architecture on reproductive success.
• Analyze sex allocation patterns in a species with decoupled flowering.

Main Methods:

• Manipulated floral bud removal by position and flowering sequence.
• Performed pollination treatments (open and supplemented).
• Quantified pollen production, dry mass, seed production, fruit set, and bud development.

Main Results:

• Pollen production and dry mass decreased acropetally (bottom to top).
• Basal flowers showed male-biased sex allocation.
• Seed production, fruit set, and bud development declined basipetally (proximal to distal).
• Thinning by flowering sequence did not affect reproductive success.

Conclusions:

• Inflorescence architecture significantly influences resource allocation in decoupled flowering systems.
• Fixed ovule production can modify the impact of architectural effects on sex allocation.
• Positional effects within the inflorescence are more critical than flowering sequence for reproductive success.