Purpose To understand the invasion and ecological adaptability patterns of Galinsoga quadriradiata, the effects of various environmental factors on the seed germination and emergence were measured by indoor determination.
Method Using seeds of G. quadriradiata collected from Kunming and Zhaotong as experimental materials, they were cultivated in a controlled indoor incubator to analyze the effects of different temperatures, light conditions, pH values, salt stress, osmotic potentials, soil humidity levels, and depths on seed germination and emergence.
Results Under constant temperature conditions of 15-30 ℃, the germination rate of G. quadriradiata seed was relatively high, with the highest germination rate at 20 ℃; under variable temperature conditions, seeds could also germinate well when the nighttime temperature exceeded 10 ℃. The germination rate was higher under light condition than under dark condition. Under pH 4-10 conditions, the germination rate could reach more than 94%. When the NaCl concentration was below 0.08 mol/L, there was no significant difference in germination rate compared to the control; when the NaCl concentration was 0.24 mol/L, the germination rate was only about 1%. When the osmotic potential was higher than −0.2 MPa, there was no significant difference in germination rate compared to the control; when the osmotic potential was −0.8 MPa, the germination rate of seeds in Kunming area dropped to below 10%, while seeds in Zhaotong area did not germinate. The soil relative humidity must be greater than 60% to meet the germination conditions, and the germination rate was highest when the soil relative humidity was 100%. Seeds sown on the soil surface had the highest germination rate, and it was difficult for seedlings to emerge when the seed depth was 6 cm.
Conclusion The seeds of G. quadriradiata have wider ecological adaptability, and the adaptability of G. quadriradiata in Kunming area is wider than that of G. quadriradiata in Zhaotong area.
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