【導讀】意見，并作為畢業(yè)論文工作檢查的主要依據(jù)。士學位論文成冊的主要內(nèi)容之一。、成分、理化性質、殺菌范圍等。了解殺菌劑多菌靈的藥害特性。減率、根重增減率的影響。本實驗的實驗材料是經(jīng)過選種的花生種子、玉米種子以及大豆種子。用不同濃度的多菌靈。質的研究一直未停止過。理下的發(fā)芽率、根腫度、根重增減率、根長增減率，從而得出最適用藥濃度。農(nóng)民科學用藥提供一些有關理論依據(jù)。箱中培養(yǎng)3—5天后進行對比。[4]李敏.作物藥害產(chǎn)生的原因、預防及對策[J].種業(yè)大觀，2021,3:35.

　　

【正文】 senescence in wheat (Triticum aestivum L。 Tripathi et al., 1982). C. ACTION MECHANISMS In general, most fungicides act by inhibiting the energy metabolism, blocking biosynthesis or altering cell membranes of the fungus (Dominguez, 1998). Depending on where the cell is attacked, fungicides can act on the cell wall, the cytoplasm membrane, the protoplast, the mitochrondria, the ribosomes, or the nucleus. Thus, for example, carbendazim, a systemic fungicide with curative and protective action, inhibits the 宜春學院畢業(yè)論文 development of the germinal tubes, the formation of the apresoria, and the growth of the nucleus (Tomlin, 1994). Although it is generally accepted that the activity of these pounds derives from their direct antibiotic action on the invading microanism, speculation has arisen concerning how the plant39。s defense systems may bolster the effectiveness of the fungicide (Ward et al., 1980). Thus in soy, for example, the effectiveness of metalaxyl, a systemic fungicide active against oomycete fungi (Fisher amp。 Hayes, 1982), has been correlated with the accumulation of glyceolin, an antimicrobial plant phytoalexin (Ward et al., 1980). Later it was reported that, in potato tubers, metalaxyl is effective against Fusarium sp. and Alternaria sp., fungi for which metalaxyl shows no direct toxicity (Barak et al., 1984). Similarly, it has been suggested that the fungicide fosetyl and Cu (OH)z, widespectrum fungicides and bactericides, may be involved in activating some defensive responses in the host (Guest, 1984。 Nemestothy amp。 Guest, 1990。 Jones etal., 1991). In this respect, Molina et al. (1998) demonstrated that in Arabidopsis the innatedefense mechanism of the plant contributes to the effectiveness of various fungicides. D. PHYTOTOXICITY Apart from the simple idea that a biocide should be specific in its target (a fungicide should be toxic for a fungus, an insecticide for an insect, etc.), only a few articles have been publishedon the issue of whether different chemical products alter or inhibit the physiological or metabolical activity of plants. In this sense, Bader and AbdelBasset (1999) showed for the first time that fungicides of the triforin type (saprol) strongly inhibit electrontransport reactions of , though effective fungicides, can bee phytotoxic, stunting plant growth and causing visible damage to seedlings (Marc et al., 1996). Some products, such asbenlate DF (benomyl), depress photosynthesis (Marc et al., 1996). Finally, carbendazim does not inhibit photosynthesis but does lower the levels of foliar calcium (Ca), promoting chlorosis in Petunia (Marc et al., 1996). In some cases the cause of the phytotoxicity of the fimgicide proved to be related to certain products resulting from the breakdown of the fungicide itself after peration of the host cell and integration into the cell metabolism. Thus Marc et al.(1997) demonstrated that dybutylurea, a product of the breakdown ofbenomyl, can be particularly responsible for the phytotoxicity of the fungicide benlate DF. Other ingredients of the degradation of benlate also contribute to the phytotoxicity of the fungicide (Marc et al., 1997). To understand the effects of fungicides on the physiology of plants, Garcia et al. (2021) analyzed the manner in which the different concentrations of a fungicide affect biomass production,the content of pigments, and the levels of nutrients by foliar application in tobacco plants. The fungicide used in this experiment was carbendazim (carb) because it is one of the most extensively used fungicides in southeastern Spain, a zone with intensive agriculture, and 宜春學院畢業(yè)論文 because it is a broadspectrum preventive fungicide, applied to a large number of crops (Tomlin,1994). The fungicide was applied at 100% purity and at three different concentrations: mM(carb 1), mM (carb 2), and mM (carb 3). The control treatment consisted of not applying carbendazim. Taking into account all of the parameters analyzed in this experiment, these researchers found that, in relation to control, the different treatments with carbendazim caused generally similar effects. The application of the dosage lower than remended ( raM)resulted in greater dry weight as well as in greater nitrogen (N) and potassium (K) concentrations than in control. This reflects the beneficial effect that the foliar application ofcarbendazim can exert on the accumulation of these essential nutrients, as well as on the growth and development of tobacco plants. The application of the remended dosage of carbendazim () slightly reduced values, with respect to the lesser dosage, for the dry weight, nutritional levels, all foliar pigments, P, Ca, and magnesium (Mg). These results reflect a harmful, though not severe, effect of carbendazim on the nutritional staus, pigment biosynthesis, and biomass. Therefore, the results, in revealing slight phytotoxicity, only partially support the remendation of the use of this product. Finally, these authors found that the application of the dosage heavier than remended ( mM) significantly reduced dry weight, all foliar pigments, and nutrients with respect to the other dosages and control. These data clearly show that this fungicide, applied in excess, is toxic for healthy tobacco plants. Additionally, symptoms of necrosis were found in old leaves after the application of increasing dosages of the fungicide. In short, the experimental results imply that the negative effects of carbendazim can be avoided by lowering the levels normally applied in agriculture. Nevertheless, the possibility remains that this reduction in the application rate will result in lower effectiveness against pathogens, although this problem requires further investigation.