Contrasting allocation patterns in wheat and weeds: allometric belowground and reproductive investment versus optimal partitioning adaptations

Jiazhen Xi ¹ Shengtao Shi ¹ Yizhong Rong ² Jie Liu ¹ Li Zhang ^1*

• ¹ Nanjing Forestry University, Nanjing, China
• ² Anhui Agricultural University, Hefei, Anhui Province, China

Modeling differences in biomass allocation between wheat and weeds'specificallydifferences in biomass allocation to shoots (aboveground biomass), roots (belowground biomass), and reproductive tissuesseed mass (reproductive biomass)enhances our understanding of sustainable weeds management. However, few studies have examined the effects ofhow fertilization and planting density on influence biomass accumulation and allocation at both vegetative and reproductive stages within a wheat-weed community. We To address this gap, we conducted a greenhouse experiment by growing wheat (Triticum aestivum L.), wild oats (Avena fatua L.), and barnyard grass (Echinochloa crusgalli (L.) P. Beauv.) under varying planting densities (4, 8, 12, and 16 individuals per pot) and fertilization treatments (1.018 g N per pot of urea). After six months at theof vegetative stage growth and one additionalseven months at the reproductive stage, we measured the above-ground and below-ground biomass of individual plants inat both phasesstages, and reproductive biomassseed mass during the reproductive stage. Wheat and weedsWe found that the biomass of wheat and weeds in various organs increased with fertilization and but decreased with higher planting density, with no interaction between these factorsthe two. Wheat allocated more biomassto belowground to roots than shoots and more to reproductive than aboveground tissues and more to reproductive than vegetative biomass, regardless ofunaffected by fertilization or planting density, following allometric allocation theory. In contrast, some weeds distributed biomass similarly between stems shoots and roots at planting densities of 4 and 12 under fertilization, or allocated more biomass to roots than to stem shoots growthat these densities.; Additionally, some weeds also achieved higher yields at both small and large sizes under planting densities of 12 and 16, ,respectively, suggesting higher greater phenotypic plasticity. This study provides a comprehensive examination analysis of biomass allocation differences in between wheat and weeds throughout their life cycles, offering insights into plant adaptation strategies and potential guidancepractical applications for optimizingfuture agricultural management.