Xi Jiazhen, Shi Shengtao, Rong Yizhong, Liu Jie, Zhang Li
Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, College of Ecology and the Environment, Nanjing Forestry University, Nanjing, China.
School of Resources and Environment, Anhui Agricultural University, Hefei, China.
Front Plant Sci. 2025 Apr 24;16:1542205. doi: 10.3389/fpls.2025.1542205. eCollection 2025.
Modeling differences in biomass allocation between wheat and weeds-specifically to shoots (aboveground biomass), roots (belowground biomass), and seed mass (reproductive biomass)-enhances our understanding of sustainable weeds management. However, few studies have examined how fertilization and planting density influence biomass accumulation and allocation at both vegetative and reproductive stages within a wheat-weed community.
To address this gap, we conducted a greenhouse experiment growing wheat ( L.), wild oats ( L.), and barnyard grass ( (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 of vegetative growth and one additional month at the reproductive stage, we measured aboveground and belowground biomass at both stages, and reproductive biomass during the reproductive stage.
We found that the biomass of wheat and weeds increased with fertilization but decreased with higher planting density, with no interactions between these factors. Wheat allocated more biomass to roots than shoots and more to reproductive than vegetative biomass, regardless of fertilization or planting density, following allometric allocation theory. In contrast, weeds distributed biomass similarly between shoots and roots at planting densities of 4 and 12 under fertilization or allocated more biomass to roots than to shoots at these densities. Additionally, some weeds achieved higher yields at both small and large sizes under planting densities of 12 and 16, respectively, suggesting greater phenotypic plasticity. This study provides a comprehensive analysis of biomass allocation differences between wheat and weeds throughout their life cycles, offering insights into plant adaptation strategies and practical applications for optimizing agricultural management.
模拟小麦与杂草之间生物量分配的差异——特别是地上部分（地上生物量）、根系（地下生物量）和种子质量（生殖生物量）——有助于我们更好地理解可持续杂草管理。然而，很少有研究探讨施肥和种植密度如何影响小麦-杂草群落营养生长和生殖生长阶段的生物量积累与分配。
为填补这一空白，我们进行了一项温室试验，在不同种植密度（每盆4、8、12和16株）和施肥处理（每盆施1.018克尿素氮）条件下种植小麦（普通小麦）、野燕麦（野燕麦）和稗草（稗）。在营养生长六个月和生殖生长额外一个月后，我们测量了两个阶段的地上和地下生物量以及生殖阶段的生殖生物量。
我们发现，小麦和杂草的生物量随施肥量增加而增加，但随种植密度升高而降低，且这些因素之间没有相互作用。根据异速分配理论，无论施肥或种植密度如何，小麦分配到根系的生物量多于地上部分，分配到生殖部分的生物量多于营养部分。相比之下，在施肥条件下，种植密度为4和12时，杂草在地上和地下部分之间的生物量分配相似，或者在这些密度下分配到根系的生物量多于地上部分。此外，一些杂草在种植密度分别为12和16时，无论大小都能获得更高产量，这表明其具有更大的表型可塑性。本研究全面分析了小麦和杂草在其整个生命周期中的生物量分配差异，为植物适应策略以及优化农业管理的实际应用提供了见解。
