Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis

Area of Science:

• Agricultural Science
• Plant Biology
• Root Physiology

Background:

• Understanding plant root morphology is crucial for function.
• Detailed root characteristic data for fine-rooted plants like rice are scarce.

Purpose of the Study:

• To quantitatively classify rice root types: fine lateral roots (FLRs), thick lateral roots (TLRs), and nodal roots (NRs).
• To analyze the dynamics of root mean diameter (MD), length, and surface area percentage (SAP) across growth stages.
• To evaluate the impact of nitrogen and water availability on rice root dynamics.

Main Methods:

• Pot experiments conducted over three years.
• Investigated three rice cultivars, three nitrogen (N) rates, and three water regimes.
• Quantitative analysis of root length, mean diameter, and surface area percentage for different root types.

Main Results:

• 'Yangdao 6' cultivar showed longer roots, smaller FLR MD, larger TLR/NR MD, and higher SAPT, indicating superior N and water uptake.
• High N increased root length and lateral root MD, but decreased SAPF and SAPT while increasing SAPN.
• Water stress increased root length, diameter, SAPF, and SAPT, but decreased SAPN.

Conclusions:

• Rice plants adjust root morphology, favoring lateral root proliferation, to enhance nitrogen and water uptake under nutrient and water stress.
• Quantitative root trait analysis provides insights into cultivar performance and adaptation strategies.