Sugarcane Straw and its Phytochemicals as Growth Regulators of Weed and Crop Plants

Abstract

The present study investigates the effect of soil amended with sugarcane straw leachate and its constituents on root elongation of weed and crop plants. The influence of soil biotic and abiotic factors on plant growth were also evaluated through assays in both autoclaved soil and sand. In unsterile soil, straw leachates stimulated root growth of some test plants at 6 g dry straw ls À1 and inhibited root elongation at higher concentrations. A bioassay guided process of the bioactive leachate constituents led to the isolation of vanillic, syringic and ferulic acids. These compounds were also assayed on the test plants in the three mentioned substrates. In unsterile soil, phenolics stimulated the growth of some species at 19 mg l À1 . Higher phenolics concentrations were inhibitory. The concentration needed to inhibit 25% root elongation (EC 25 ) was calculated from the dose-response curves. The concentration of phenolics in the leachate (64 g dry straw l À1 ) was estimated to be 187 mg l À1 (ferulic acid), 131 mg l À1 (vanillic acid) and 20 mg l À1 (Syringic acid). In general, these concentrations were below the EC 25 values determined in unsterile soil indicating that these compounds cannot completely explain the strong inhibitory activity of sugarcane straw leachates. The role of soil factors on phytotoxicity of sugarcane straw leachate and its identified growth regulators is also discussed.

Comparative Performance of Sugarcane Bagasse and Black Polyethylene as Mulch for Squash (Cucurbita pepo L.) Production

“…documented the presence of allelopathic chemicals in sugarcane leaves (De Carvalho et al, 2005;Singh et al, 2003;Viator et al, 2006) and straw (Sampietro et al, 2007;Sampietro et al, 2005;Sampietro & Vattuone, 2006a, 2006bWang et al, 1967). Rodrigues et al (2001) documented that the breakdown of sugarcane bagasse lignocellulosic material produced toxic compounds that inhibit cellular growth.…”

Sugarcane Field Residue and Bagasse Allelopathic Impact on Vegetable Seed Germination

“…Sugarcane field residue leachates also reduced the growth of numerous weedy species, such as arrowleaf sida (Sida rhombifolia L.) (Sampietro et al, 2007). Three allelopathic compounds, ferulic, vanillic and syringic acids that exhibited allelopathic characteristics have been isolated from sugarcane field residue leachates (Sampietro et al, 2005;Sampietro & Vattuone, 2006b). Beggarticks (Bidens subalternans L.) and wild mustard (Brassica campestris L.) seedling root elongation was reduced due to the presence of phenolic compounds (Sampieto & Vattuone, 2006a).…”

“…Depending on the concentration, sugarcane leachate has either promoted or inhibited growth (Sampietro & Vattuone, 2006b). At sugarcane field residue levels typically found in the field, the leachate would inhibit growth, but at a lower 6 g/L concentration the extract promoted root growth of pigweed (Amaranthus quitensis L.), radish (Raphanus sativus L. var.…”

“…'Supergauchazo'), wheat (Triticum aestivum L. var. 'Pegaso'), and wild mustard (Brassica campestris L.) (Sampietro & Vattuone, 2006b). Rodrigues et al (2001) documented that the breakdown of sugarcane bagasse lignocellulosic material produced toxic compounds that inhibit cellular growth.…”

“…The long frost-free growing season in southern Louisiana, 230-290 days a year, that favors sugarcane production, also provides an ideal environment for vegetable production. Unfortunately, the sugarcane field residue and bagasse material also has the potential to produce allelopathic compounds that may adversely impact crop production if used as a natural mulch (Rodrigues et al, 2001;Sampietro et al, 2005Sampietro et al, , 2007Sampietro & Vattuone, 2006a, 2006b. Research was initiated to determine the allelopathic impact of sugarcane field residue and sugarcane bagasse extracts on seed germination of tomato, Chinese kale, and cucumber.…”