Related Experiment Video
Updated: Mar 3, 2026

In vivo and In vitro Infection of Potato Roots with Plant Parasitic Nematodes for the Assessment of Induced Structural Changes
Published on: February 28, 2025
Reducing nitrogen with dense planting increase sweetpotato storage roots quantity via favoring starch synthesis over
Heyan Pan1, Xue Hai1, Xin Guo1
1School of Tropical Agriculture and Forestry, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan, China.
Abstract:
Excessive nitrogen (N) inhibits crop development, yet the synergistic effects of reducing nitrogen with dense planting on sweetpotato storage root (SR) formation remain unclear. This study evaluated four N levels (0, 23, 46, and 69 mg N kg-1 soil) and three planting spacings (0.25, 0.20, and 0.15 m). Results indicated that medium density with medium N (MDMN) significantly outperformed the traditional low-density high-N (LDHN) treatment. From 15 to 30 days after planting (DAP), MDMN enhanced root number, length, and volume, while by 45 DAP it increased SR number, root activity, and N accumulation. MDMN upregulated IbKNOX1 and IbARF5, elevating ZR and IAA levels while reducing GA3, thereby promoting starch accumulation via increased IbSUS and IbAGP expression. Concurrently, lignin biosynthesis was suppressed through downregulation of IbPOD and lignin-related genes. Collectively, MDMN promotes SR formation by optimizing hormonal balance to favor starch synthesis over lignification.
Related Concept Videos
Basic Plant Anatomy: Roots, Stems, and Leaves
Overview of Metabolism
Plant Metabolism
Sunlight, the primary source of energy in plants, is first absorbed by the chlorophyll pigments present in their leaves. Plants then use this energy to carry out photosynthesis, where water is oxidized into oxygen and carbon dioxide...
Key Elements for Plant Nutrition
Inorganic Nitrogen Assimilation
Sugars as Energy Storage Molecules

