Crop Root Behavior Coordinates Phosphorus Status and Neighbors: From Field Studies to Three-Dimensional in Situ Reconstruction of Root System Architecture    

Abstract

Root is a primary organ to respond to environmental stimuli and percept signals from neighboring plants. In this study, root responses in maize (Zea mays)/soybean (Glycine max) intercropping systems recognized soil phosphorus (P) status and neighboring plants in the field. Compared to self culture, the maize variety GZ1 intercropping with soybean HX3 grew much better on low P, but not in another maize variety, NE1. This genotypic response decreased with increasing distance between plants, suggesting that root interactions were important. We further conducted a detailed and quantitative study of root behavior in situ using a gel system to reconstruct the three-dimensional root architecture. The results showed that plant roots could integrate information on P status and root behavior of neighboring plants. When intercropped with its kin, maize or soybean roots grew close to each other. However, when maize GZ1 was grown with soybean HX3, the roots on each plant tended to avoid each other and became shallower on stratified P supply, but not found with maize NE1. Furthermore, root behavior in gel was highly correlated to shoot biomass and P content for field-grown plants grown in close proximity. This study provides new insights into the dynamics and complexity of root behavior and kin recognition among crop species in response to nutrient status and neighboring plants. These findings also indicate that root behavior not only depends on neighbor recognition but also on a coordinated response to soil P status, which could be the underlying cause for the different growth responses in the field.

Photophobic behavior of maize roots

“…We propose a new term for this escape behavior of illuminated roots-root photophobism. This Darwinian view of plant roots, with the root apex acting as brain-like "command center", 2,6,[20][21][22][23] will allow a better understanding of the true communicative and behavioral nature of plants and their roots, 5,27,28,[34][35][36] which is essential for the sustainable agriculture of the future 5,36 …”

Genotypic recognition and spatial responses by rice roots

“…Further evidence for differential responses came from observing root systems grown in growth medium and soil environments. Maize and soybean root systems grew differently when grown alone or with the other species; and even for the same soybean variety, differences in root behavior were observed when intercropped with different maize varieties (15).…”

“…Aboveground interactions have been studied in greater detail, in part because of the accessibility of aerial tissue. However, there is growing interest in root-system architecture and its effect on plant function and fitness (12,15). Studies of root-system architecture suggest that root systems develop differently in the presence of other root systems.…”

“…Plants not only detect but also respond to changes in their environment, exhibiting adaptation in their morphology and physiology in response to environmental stimuli (9-14), such as alteration in total root length, root system volume, and root depth (15,16). Phenotypic plasticity of plants in response to environmental heterogeneity may have consequences for plant fitness.…”

Effect of neighboring competition on photosynthetic characteristics and biomass allocation of Chinese fir seedlings under low phosphorus stress

“…但胁迫时期对地上部分生物量的影响不显著 ( (Pierik et al, 2013;Schmid et al, 2015)。 植物在对邻株竞争做出响应之前必先通过某些 特定途径来感受邻株植物的存在。近年来, 许多学 者分别从植物对光竞争信号(R:FR)、 根际养分浓度、 根系分泌物、挥发性植物激素以及菌根释放化学信 号等方面试图阐明邻株竞争的响应机制 (Fang et al, 2011;Pierik et al, 2013Pierik et al, , 2014Schmid et al, 2015), 但仍无法阐明邻株杉木间竞争策略的内在机理。而 蛋白组学技术有望成为揭示竞争植物相互影响时, 植物通过体内蛋白合成的调控从而诱导生理形态响 应变化的最重要的一种研究手段 (Schmid et al, 2013;Depuydt, 2014)。 基金项目 国家自然科学基金(31100472和3137-0619)和福建省自然科学基金杰出青年基金(2014J-06009)。 致谢 本研究得到福建农林大学林学院青年教师科…”