Effect of Environmental Factors on Seed Germination and Early Seedling Emergence of Carolina geranium (Geranium carolinianum)

Abstract

Carolina geranium (Geranium carolinianum) is an emerging invasive weed in rape and wheat fields in China. A better understanding of its germination and emergence ecology will enable the development of integrated weed control strategies. In this study, we investigated the effects of temperature, photoperiod, soil water content, salinity, and burial depth, on germination and emergence of Carolina geranium. Germination percentages were over 74% under 15/20 and 20/25 oC night/day temperature regimes. Germination rate was independent of light/dark regime. Increasing salinity reduced germination of Carolina geranium from 81.1% at 0 mM to 0% at 160 mM NaCl. Seeds germination was peaked at 50% soil moisture, but was completely inhibited at < 20% and > 90%. The seedling emergence above 82.2% was observed when seeds were placed at a depth from 0 to 1 cm, and no seedlings emerged from seeds placed at a depth of 7 cm. Current work provide the basic information to effectively prevent and control this invasive weed in Chinese rape and wheat fields.

The effect of environmental factors on seed germination and emergence of cutleaf geranium

“…Thus, the emergence of G. dissectum may be controlled by tillage operations to bury the seeds at soil depths of 4 cm or more. Emergence of G. carolinianum seedlings was higher than 80% at zero and 1 cm depths, whereas no emergence was observed when the seeds were buried under 7 cm of soil (Liu et al, 2018). Similarly, emergence of A. sterilis seeds was the highest when buried at 0 to 2 cm, but declined thereafter and was nil at 15 cm (Hassanpour-bourkheili et al, 2021b).…”

“…These events ultimately culminate in poor plant establishment (Foti et al, 2019). Increasing levels of salinity stress led to a reduction in the germination of Carolina geranium (Geranium carolinianum L.) seeds, and germination percentage was almost halved at 80 mM NaCl and reached zero at 160 mM NaCl (Liu et al, 2018). The NaCl concentration required for 50% reduction in L. rigidum seed germination was 130mM and a NaCl concentration of 250 mM resulted in 0% germination (Thompson et al, 2021).…”

“…Flooding stress may negatively affect the viability of seeds depending on the species and flooding duration (Kolb, Joly, 2010). Germination of G. carolinianum decreased drastically when the seeds were exposed to flooding stress (Liu et al 2018). The seeds of Caperonia palustris (L.) A.St.-Hil were able to survive the flooding condition and showed a germination percentage of 25 percent (Koger et al, 2004).…”

Germinação de sementes de Amaranthus deflexus L. submetidas a diferentes condições de tempera-tura e estresse salino

“…The lowest GSI were again observed at the temperatures of 20, 40, and 30-40 °C (Figure 5C). Liu et al (2017) evaluated the influence of temperature and light on the germination and emergence of Geranium carolinianum and found that the alternating temperatures of 15/20 °C and 20/25 °C (day/night) was the most appropriate to express the maximum potential germination of this species, regardless of light. Ataíde et al (2016) found higher GSI in Melanoxylon brauna when grown at 30 ºC.…”

Managing herbicide resistance in China

“…These cultural practices disrupt the life cycles of weeds and change the surrounding weed community based on the growth characteristics of each crop (Buhler 2002). In Chinese agricultural production, crop rotation is usually adopted by rotation of a grass crop (e.g., corn, wheat, rice) with a broadleaf crop (e.g., soybean, cotton, canola), or rotation of a wetland crop (e.g., rice) with a dryland crop (e.g., wheat) (Liu et al 2018;Zhang 2003). In addition, growers often attempt to enhance crop competitiveness through the use of mulching (Yang et al 2018), allelopathy (Li et al 2019), cover crops, and full-season cultivars combined with suitable planting timing and planting density (Deng et al 2010).…”