Seed Germination and Seedling Emergence of Giant Sensitiveplant (Mimosa Invisa)

Abstract

Giant sensitiveplant is a dominant weed in many tropical and subtropical countries because it is highly competitive and is difficult to clear by hand. Experiments were conducted to determine the effect of various environmental factors on giant sensitiveplant seed germination and seedling emergence. Light was not required for germination, though germination was stimulated by seed scarification, suggesting that inhibition of germination is mainly due to the seed coat. Germination of scarified seed was not influenced by a range of alternating temperatures. Germination increased by exposure to higher temperatures, such as might occur when vegetation is burnt, as simulated by placing nonscarified seed in an oven for 5 min. Germination increased as exposure temperature was increased from 25 C to 120 C but declined progressively with further increases and there was no germination after exposure to 200 C. Moderate salinity and osmotic stress did not inhibit germination and some seed germinated at 250 mM sodium chloride (55%) and osmotic potential of −1.0 MPa (13%). Germination was greater than 79% over a pH range of 4 to 10. Seedling emergence was 80 to 94% at depths of 0 to 2 cm but decreased progressively at deeper depths, and no seedlings emerged from seed buried at 10 cm. The results of this study identify some of the factors enabling giant sensitiveplant to be a widespread and problematic weed in the humid tropics and provide information that could contribute to its control.

Germination Ecology of Chinese Sprangletop (Leptochloa chinensis) in the Philippines

“…These data suggest that this species might not be a problematic weed in high-saline soils. Some weeds, on the other hand, can germinate even at 250 mM NaCl (Chauhan and Johnson 2008b).…”

“…Factors such as soil moisture, salinity, temperature, and light influence the germination and emergence of several weed species (Chauhan et al 2006b;Chauhan and Johnson 2008b). Weed seed requiring light, for example, would emerge when present close to the soil surface and such species are potentially more likely to be prevalent in no-till systems.…”

Seed Germination and Seedling Emergence of Nalta Jute (Corchorus olitorius) and Redweed (Melochia concatenata): Important Broadleaf Weeds of the Tropics

“…Our study also suggests that either no-till or mulch systems will have no influence in terms of light exposure affecting germination. Species having a hard seed coat have been reported to have light-independent germination (e.g., Chauhan and Johnson 2008b). Temperature may also affect seed germination and in part govern seasonality and range expansion.…”

Factors Affecting Tausch’s Goatgrass (Aegilops tauschii Coss.) Seed Germination and Seedling Emergence

“…Response of germination to light varied from species to species (Crisraudo et al, 2007;Gallagher and Cardina 1998). Seeds of some species required light to stimulate their germination (Chauhan and Johnson 2009;Chauhan and Johnson 2008b;Chauhan et al, 2006), but others germinated equally well in light and dark (Chauhan and Johnson 2008a;Teuton et al, 2004). Lynn.…”