Influence of Rhizosphere Oxygen Concentration on Rice Root Growth

Abstract Background Nitrogen-based nutrients are the main factors affecting rice growth and development. Root systems play an important role in helping plants to obtain nutrients from the soil. Root morphology and physiology are often closely related to above-ground plant organs performance. Therefore, it is important to understand the regulatory effects of nitrogen (N) on rice root growth to improve nitrogen use efficiency. Results In this study, changes in the rice root traits under low N (13.33 ppm), normal N (40 ppm) and high N (120 ppm) conditions were performed through root morphology analysis. These results show that, compared with normal N conditions, root growth is promoted under low N conditions, and inhibited under high N conditions. To understand the molecular mechanism underlying the rice root response to low and high N conditions, comparative proteomics analysis was performed using a tandem mass tag (TMT)-based approach, and differentially abundant proteins (DAPs) were further characterized. Compared with normal N conditions, a total of 291 and 211 DAPs were identified under low and high N conditions, respectively. The abundance of proteins involved in cell differentiation, cell wall modification, phenylpropanoid biosynthesis, and protein synthesis was differentially altered, which was an important reason for changes in root morphology. Furthermore, although both low and high N can cause nitrogen stress, rice roots revealed obvious differences in adaptation to low and high N. Conclusions These results provide insights into global changes in the response of rice roots to nitrogen availability and may facilitate the development of rice cultivars with high nitrogen use efficiency through root-based genetic improvements.

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Single‐wall and multi‐wall carbon nanotubes promote rice root growth by eliciting the similar molecular pathways and epigenetic regulation

IET Nanobiotechnology ◽

10.1049/iet-nbt.2015.0046 ◽

2016 ◽

Vol 10 (4) ◽

pp. 222-229 ◽

Cited By ~ 11

Author(s):

Shihan Yan ◽

Hao Zhang ◽

Yan Huang ◽

Junjun Tan ◽

Pu Wang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Root Growth ◽

Epigenetic Regulation ◽

Rice Root ◽

Molecular Pathways ◽

Multi Wall Carbon Nanotubes

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Soil Physical Conditions Affecting Rice Root Growth: Bulk Density and Submerged Soil Temperature Regime Effects 1

Agronomy Journal ◽

10.2134/agronj1976.00021962006800010007x ◽

1976 ◽

Vol 68 (1) ◽

pp. 23-26 ◽

Cited By ~ 9

Author(s):

S. Kar ◽

S. B. Varade ◽

T. K. Subramanyam ◽

B. P. Ghildyal

Keyword(s):

Root Growth ◽

Soil Temperature ◽

Bulk Density ◽

Temperature Regime ◽

Rice Root ◽

Physical Conditions ◽

Soil Temperature Regime ◽

Submerged Soil

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An Integrated Analysis of the Rice Transcriptome and Metabolome Reveals Root Growth Regulation Mechanisms in Response to Nitrogen Availability

International Journal of Molecular Sciences ◽

10.3390/ijms20235893 ◽

2019 ◽

Vol 20 (23) ◽

pp. 5893 ◽

Cited By ~ 3

Author(s):

Wei Xin ◽

Lina Zhang ◽

Wenzhong Zhang ◽

Jiping Gao ◽

Jun Yi ◽

...

Keyword(s):

Root Growth ◽

Differentially Expressed Genes ◽

Nitrogen Availability ◽

Rice Root ◽

Integrated Analysis ◽

High Nitrogen ◽

Rice Roots ◽

Regulation Mechanisms ◽

Low Nitrogen ◽

Nitrogen Conditions

Nitrogen is an essential nutrient for plant growth and basic metabolic processes. Root systems play an important role in the ability of plants to obtain nutrients from the soil, and are closely related to the growth and development of above-ground plants. Root morphology analysis showed that root growth was induced under low-nitrogen conditions and inhibited under high-nitrogen conditions. To better understand the molecular mechanisms and metabolic basis underlying the rice root response to nitrogen availability, an integrated analysis of the rice root transcriptome and metabolome under three environmental conditions (low-, control, and high-nitrogen conditions) was conducted. A total of 262 and 262 differentially level metabolites were identified under low- and high-nitrogen conditions, respectively. A total of 696 and 808 differentially expressed genes were identified under low- and high-nitrogen conditions, respectively. For both the differentially expressed genes and metabolites, KEGG pathway analysis indicated that amino acid metabolism, carbon and nitrogen metabolism, phenylpropanoid metabolism, and phytohormones’ signal transduction were significantly affected by nitrogen availability. Additionally, variable levels of 65 transcription factors (TFs) were identified in rice leaves exposed to high and low nitrogen, covering 22 TF families. These results also indicate that there is a significant difference in the transcriptional regulation mechanisms of rice roots between low and high nitrogen. In summary, our study provides new information for a further understanding of the response of rice roots to low-nitrogen and high-nitrogen conditions.

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Evaluation of Putative Allelochemicals in Rice Root Exudates for Their Role in the Suppression of Arrowhead Root Growth

Journal of Chemical Ecology ◽

10.1023/b:joec.0000042075.96379.71 ◽

2004 ◽

Vol 30 (8) ◽

pp. 1663-1678 ◽

Cited By ~ 49

Author(s):

Alexa N. Seal ◽

Terry Haig ◽

James E. Pratley

Keyword(s):

Root Growth ◽

Root Exudates ◽

Rice Root

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Rice root growth in relation to size, quantity, and rigidity of pores

Plant and Soil ◽

10.1007/bf01928524 ◽

1975 ◽

Vol 43 (1-3) ◽

pp. 627-637 ◽

Cited By ~ 8

Author(s):

S. Kar ◽

B. P. Ghildyal

Keyword(s):

Root Growth ◽

Rice Root

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Soil physical environment affecting root growth of upland rice

The Journal of Agricultural Science ◽

10.1017/s0021859600039137 ◽

1979 ◽

Vol 93 (3) ◽

pp. 719-726 ◽

Cited By ~ 3

Author(s):

S. Kar ◽

S. B. Varade ◽

B. P. Ghildyal

Keyword(s):

Root Growth ◽

Bulk Density ◽

Physical Environment ◽

Oxygen Diffusion ◽

Dry Weight ◽

Moisture Stress ◽

Rice Root ◽

Soil Types ◽

Low Density ◽

Depth Of Penetration

SUMMARYRoot growth of rice (Oryza saliva L.) is frequentlyinhibited by an adverse physical environment resulting from high moisture stress and strength of soilunder upland conditions, and the effects are often reflected in poor performance of the crop. This necessitates a critical understanding of rice root growth under varying soil physical conditions.The growth responses of the rice root system to the interaction between moisture regime and bulk density of soil as well as to the induced soil physical characteristics were assessed under controlled glasshouse conditions. Four moisture regimes: 0 (M1), 0–20 (M2), 0–350(M3), and 350–10000 (M4) mb, were superimposed on low, medium and high bulk density treatments in clay, loam and sandy loam soils. The soil physical environment was characterized by measurements of moisture distribution, penetrationenergy and oxygen diffusion rate in soils as functions of depth.A low moisture stress of 20 mb in low density soils favoured rice root growth. In low density soils, even though the number of roots at the base (proximal end) was maximum under M1, the depth of penetration, volume and dry weight of root were significantly more underM2 than under M1; M3 and M4. Irrespective of bulk density, even though oxygen diffusion rates in soils under M3 and M4 were greater than those under M1 and M2, the number of roots at the base, volume and dry weight of the root system decreased under M3 and M4 owing to low moisture content and high penetration energy in the surface layer (0–5 cm) of all the soil types. Lower moisture content and higher penetration energy at higher bulk densities of the soil types significantly reduced the root growth and especially the depth of penetration.

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