Environmental Factors Affecting Germination of Tropical Soda Apple (Solanum viarum)

Abstract

Laboratory studies were conducted to determine the effect of various factors on germination of tropical soda apple. Tropical soda apple seed were found to be moderately photoblastic with 30% germination occurring in the dark. Germination increased in response to green (545 nm) and red light (650 nm) to 75 and 66%, respectively, indicating phytochrome regulation. No germination occurred in response to blue (450 nm) and far-red light (750 nm). Germination increased from 4 to 64% between 10 to 30 C, but no germination was found at 5 and 40 C. Maximum germination occurred at 30 C. A second degree polynomial (Y= −48.7 + 7.9X – 0.2X2, R2= 0.76) best fit the data. Seed germinated over a broad range of pH (2 to 14) with the highest germination occurring at pH 8 and no germination occurring at pH 2 and 14 (Y = −63.3 + 30.5X – 1.9X2, R2= 0.95). Seed germination declined as osmotic potential increased from 0 to −1.0 MPa (Y = 76.7 – 12.9X + 5.2X2, R2= 0.87). Seedling emergence was maximum from depth of 3 to 6 cm, but no seedling emergence occurred when seed were planted below 12 cm (Y = 10.2 + 17.8X – 1.6X2, R2= 0.93). Optimum germination occurred at a depth of 5.6 cm. Mechanical and sulfuric acid scarification increased the rate of germination but not the overall percentage. Tap water or hot water increased the rate of germination 26% and KNO3, GA3, or ethephon increased it 53%. Tropical soda apple seed germinated in response to variable environmental and edaphic conditions which could allow establishment in diverse ecosystems.

Germination and emergence of Ambrosia artemisiifolia L. under changing environmental conditions in China

“…These patterns are similar to the trends observed in other invasive weeds, namely Crofton Weed ( Eupatorium adenophorum ) (Lu et al . 2006), Solanum viarum (Akanda et al . 1996) and Jubatagrass ( Cortaderia jubata ) (Drewitz & DiTomaso 2004), which all showed higher germination when exposed to a 12‐h photoperiod than to continuous darkness.…”

“…These patterns appear to show the evolution of ecotypes adapting to the different temperature regimes experienced at the three locations, with the temperate site not only encountering the lowest overall temperatures, but also the greatest variation with hot, dry summers. The very broad range of temperatures under which common ragweed germinates corresponds with the wide distribution of the species in China (Zeng 2003), and is again reflected by other successful invasive weeds, such as Cortaderia jubata (8–35°C) (Drewitz & DiTomaso 2004), Solanum viarum (10–35°C) (Akanda et al . 1996) and Pueraria lobata (Susko et al .…”

“…These results indicate that common ragweed can germinate under high water stress, which explains why the species can grow with all xerophilous crops (Wang 2004) and can influence crop yield in both high and low humidity soils. Similarly, weeds like Malva pusilla (Blackshaw 1990) and Solanum viarum (Akanda et al . 1996) have been reported to germinate under a wide range of osmotic potentials.…”

Evidence for Yellow Light Suppression of Lettuce Growth¶

“…Most relevant to our research, Al-Wakeel and Hamed (26) showed more growth suppression under 'yellow' (peak output at 595 nm) than 'green' (peak output at 520 nm) light in cucumbers. Even recent studies claiming 'green' or 'yellow' light responses use unequal photosynthetic photon fluxes (26,27), do not provide sources with clean cut-off and therefore vary wavelengths other than 'green' (27), or fail to report complete spectral outputs from their lamp and filter sources (26,(28)(29)(30).…”

The effect of water stress on the temperature range for germination ofOrobanche aegyptiacaseeds

“…Akanda et al, 1996;Gan et al, 1996). Although some of the models give a good fit to the data, this paper describes a model with parameters which have clearer biological meanings.…”