Plants germination effects

The plant cell is a basic unit for germination, growth and development of plants. The allelochemicals first come in contact with the cell and then allelopathic interactions take place. Some allelochemicals have broad-spectrum activity that extends to the tissues of host plants, where their effects may be either beneficial or deleterious to plant germination, growth, development or yield. Hence, to understand the mechanisms of such intercations interactions the study of the cell and its various processes is very necessary. Therefore, this book has been been prepared (a) to make available all methods for such studies and (b) scientists can understand the scope of allelopathic research in relation to the cell. Hence, we have explained and discussed various techniques to study cell processes etc. 

Principle Phytotoxic effects of the aqueous leachate of an allelopathic plant can be tested in vitro bioassays. Test or target plants are placed in contact with 0.5 % aqueous leachate from the allelopathic plant. Germination and radicle growth can be monitored during time-course experiments (i.e. after 24,48 and 72 h of treatment), but in this chapter we will include only the results obtained after 72 h of treatment. 

Certain fungal metabolites have also been found to induce the germination of plant parasites effectively. Cotylenins 21 and 22 and fusicoccins 23 and 24 are effective inductors of S. hermonthica and O. minor seeds germination (Fig. 6.5). However, the activity of these compounds is lower than that of strigolactones (ED50 around 10 pM), the free alcohols 22 and 24 being the more active compounds.57... 

D. J. Reed, E. N. Dost, and C. H. Want, "Inorganic Eluoride Propellant Oxidizers, Vol. 1 Their Effects Upon Seed Germination and Plant... 

The various fumigants often exhibit considerable specificity toward insect pests, as shown in Table 8. The proper choice for any control operation is determined not only by the effectiveness of the gas but by cost safety to humans, animals, and plants flammabdity penetratabdity effect on seed germination and reactivity with furnishings. The fumigants may be used individually or in combination. Carbon tetrachloride has been incorporated with carbon disulfide, ethylene dichloride, or ethylene dibromide to decrease flammability, and carbon dioxide is used with ethylene oxide for the same purpose. 

P. Sathiyamoorthy, Identification of vanillic and p-coumaric acid as endogenous inhibitors of soybean seeds and their inhibitory effect on germination. J. Plant P/m-w/. /id 120 (1990). 

The effect of flavonoids on spore germination and hyphal growth of ecto-mycorrhizal fungi is poorly known. However, several metabolites relea.sed by the plant roots trigger events leading to their infection (44,55). In the saprotrophic phase, spores of several ectomycorrhizal fungi respond to stimulation by abietic acid, the diterpene resin acid, in root exudates (56). 

The term allelopathy was coined by Molisch in 1937 Q). Presently, the term generally refers to the detrimental effects of higher plants of one species (the donor) on the germination, growth, or development of plants of another species (the recipient). Allelopathy can be separated from other mechanisms of plant interference because the detrimental effect is exerted through release of chemical inhibitors (allelochemicals) by the donor species. Microbes associated with the higher plants may also play a role in production or release of the inhibitors (2). 

Encecalin (I) causes a dwarfing of lettuce shoots at concentrations from lOppm and up. On the other hand, eupatoriochromene (II) causes very little dwarfing of the seedling but does inhibit germination of lettuce at lOOppm and above. The concentration of these two chro-raenes in yellow starthistle may indeed allow for some effect to be exerted on the surrounding plant community. 

The effects of the above constituents of A. palmerl on the germination and growth of a number of plant seeds are discussed by Dr. J. M. Bradow in her chapter of this book. 

Five-g samples of wheat plant material were soaked in 150 ml of water for 10 hr at room temperature. The mixture was filtered and the filtrate used to germinate pitted morningglory (Ipomoea lacunosa L.) and ragweed (Ambrosia artemisiifolia L.) seed. The effect of the extract on germination was tested in the presence and absence of light. 

An additional study was done to determine the effects of tall fescue leachates on the growth of birdsfoot trefoil. The genotypes 237, 360 and 698 appeared to have the greatest inhibition on germination in the previous test so leaves of these plants were cut from the roots and soaked in distilled water for 24 hours. Ratios of 3, 5 and 10 g of leaves per 100 ml of distilled water were used. 

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