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Seed germination ecology of eclipta (Eclipta prostrata) in dry direct-seeded rice fields from China

Published online by Cambridge University Press:  22 August 2025

Wenyao Li
Affiliation:
Master, School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, P. R. China Master, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, P. R. China
Xingwei Lai
Affiliation:
Master, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, P. R. China
Tao Gu
Affiliation:
Associate Professor, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, P. R. China
Hongchun Wang*
Affiliation:
Associate Professor, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, P. R. China
Zichang Zhang*
Affiliation:
Professor, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, P. R. China
*
Corresponding authors: Zichang Zhang; Email: zichangzhang2009@163.com, Hongchun Wang; Email: whc23@jaas.ac.cn
Corresponding authors: Zichang Zhang; Email: zichangzhang2009@163.com, Hongchun Wang; Email: whc23@jaas.ac.cn
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Abstract

Eclipta [Eclipta prostrata (L.) L.] is an important tropical weed that has recently emerged as a problematic weed in dry direct-seeded rice (Oryza sativa L.) (DSR) fields in China. Understanding its seed germination biology and ecology is crucial for developing integrated weed management strategies in the DSR system. Laboratory experiments were conducted to investigate seed germination of E. prostrata seeds under varying environmental conditions. Germination was greatest under alternating temperature regimes of 25/15 to 40/30 C, whereas it wa-s significantly reduced at 20/10 C and completely inhibited at 15/5 C. Germination was also fully suppressed under continuous darkness, indicating strong light dependency. Eclipta prostrata seeds tolerated a broad range of pH values (4 to 10) with germination rates consistently greater than 95%. However, germination declined sharply under osmotic potentials, falling below 2% at −0.6 MPa, and being completely inhibited at −0.7 MPa. Seeds also showed moderate salt tolerance, with 50% inhibition at 150 mM NaCl and no germination at 300 mM NaCl. Exposure to radiant heat (>90 C for 5 min) prevented germination, suggesting residue burning may be an effective control measure. Seedling emergence was highest (100%) on the soil surface but declined steeply with increasing burial depth, with no emergence observed beyond 0.5 cm. Similarly, surface application of wheat (Triticum aestivum L.) straw residue (2 to 6 Mg ha−1) significantly reduced seedling emergence and biomass. These findings provide essential insights into E. prostrata germination ecology and offer practical implications for its integrated management in DSR systems.

Information

Type
Research Article
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Weed Science Society of America
Figure 0

Figure 1. Effect of simulating alternating day/night temperatures (5/15, 20/10, 25/15, 30/20, 35/25, 40/30 C) and photoperiod (day and night) for 14 d in growth chambers on germination of freshly harvested seeds of Eclipta prostrata. Vertical bars represent standard error of mean (n = 8). Different letters on the vertical bars denote significant differences at α = 0.05.

Figure 1

Figure 2. Effect of osmotic potential on germination of Eclipta prostrata seeds incubated in a growth chamber at 30/20 C day/night temperatures in a 12-h photoperiod for 14 d. The line represents a three-parameter sigmoid model fit to the data, and vertical bars represent the standard errors of the means (n = 8).

Figure 2

Figure 3. Effect of sodium chloride (NaCl) concentration on germination of Eclipta prostrata seeds incubated in a growth chamber at 30/20 C day/night temperatures in a 12-h photoperiod for 14 d. The line represents a three-parameter sigmoid model fit to the data, and vertical bars represent the standard errors of the means (n = 8).

Figure 3

Figure 4. Effect of 5-min exposures at various oven temperatures on germination of Eclipta prostrata seeds after 14 d of incubation at 30/20 C day/night temperature. The line represents a three-parameter sigmoid model fit to the data, and vertical bars represent the standard errors of the means (n = 8).

Figure 4

Figure 5. Effect of soil burial depth (cm) on seedling emergence of Eclipta prostrata. Seedling emergence was assessed until 21 d after planting (A). The seed burial depth required to inhibit 50% of maximum emergence is 0.17 cm (B). Vertical bars represent the standard errors of the means (n = 8).

Figure 5

Table 1. Parameter estimates of three-parameter sigmoid model G = Gmax/{1 + e[(xx50)/b]} fit to the seedling emergence to the different soil burial depths in Figure 5.

Figure 6

Figure 6. Effect of different amounts of residue (0, 2, 4, 6, 8, and 10 Mg ha−1) on emergence and mean dry matter of Eclipta prostrata seedlings sown in pots for 21 d. Vertical bars represent the standard errors of the means (n = 8).