# Divergent regulation of rice yield by carbon nanomaterials via biomass allocation and seed setting rate

## TL;DR

Carbon nanomaterials like C3N4 and graphene affect rice yield differently by changing how plants allocate biomass and set seeds.

## Contribution

This study reveals divergent effects of carbon nanomaterials on rice yield through biomass allocation and seed setting during reproductive stages.

## Key findings

- C3N4 reduced seed setting rate by 34.5% and rice yield by 45.1% by inhibiting biomass transfer to reproductive organs.
- Graphene increased seed setting rate by 10.7% and rice yield by 11.8% by promoting biomass allocation to reproductive organs.

## Abstract

Nanomaterials (NMs) technology has shown great potential in sustainable agriculture. However, comprehensive assessments of their impacts on the entire rice growth stages, particularly from vegetative to reproductive periods, are still limited.

Herein, two carbon NMs, graphitic carbon nitride (C3N4) and graphene, were applied via daily foliar spraying for 7 days at the rice tillering, jointing, flowering and ripening stages to systematically investigate their effects on rice growth dynamics.

Our results revealed that both C3N4 and graphene primarily affect rice growth during reproductive stages (flowering and ripening) rather than vegetative stages (tillering and jointing), with contrasting effects. C3N4 inhibited the transfer of dry biomass from vegetative organs (stems and leaves) to reproductive organs (panicle and grains), resulting in a marked reduction in seed setting rate by 34.5% and consequently a sharp yield decline by 45.1%. Conversely, graphene facilitated the allocation of more biomass to reproductive organs than vegetative organs, and increased seed setting rate by 10.7%, resulting in 11.8% higher rice yield.

Our findings underscore the differential influence of carbon NMs on rice growth mediated through modulation of biomass partitioning and seed setting rate, which is of significant relevance for developing nano-enabled strategies to promote global food security.

Illustration comparing effects of C3N4 and graphene on rice plants; C3N4 increases stem and leaf growth but decreases yield and seed setting, while graphene improves yield and seed setting but reduces vegetative growth.