Differential Response of Maize and Mungbean to Tobacco Allelopathy

Abstract

Seedling emergence and stand establishment of crops following the allelopathic crops are often affected. When the crops are grown in rotation, they are influenced by allelopathy of preceding crop. In this study, consisting of three independent experiments, allelopathic effect of tobacco, rich in several allelochemicals, on the subsequent maize and mungbean crops was investigated. In first experiment, maize and mungbean were sown in field previously occupied by tobacco or was fallow. In second experiment, maize and mungbean were planted in pots after the harvest of tobacco. Whereas in third experiment, maize and mungbean seeds were soaked in water or 2 and 4 mM nicotine and were then sown in soil-filled pots. Stand establishment, leaf emergence and growth of maize were significantly improved when grown after tobacco, whereas in mungbean these characters were suppressed when grown after tobacco. Likewise external application of nicotine improved the emergence uniformity, seedling dry weight and chlorophyll contents in maize and suppressed these parameters in mungbean. Tobacco allelopathy also increased the total soil nitrogen, zinc, iron, nicotine and total phenolics. Nicotine-induced change in chlorophyll contents and α-amylase activity seems the possible reason of differential response of maize and mungbean to tobacco allelopathy. When grown in rotation with tobacco, stand establishment and growth of maize were improved, whereas mungbean stand and growth were suppressed. In crux, allelopathic nature of the crops must be considered while making the crop rotations.

Influence of Tobacco Plant on Macronutrient Levels in Sandy Soils

“…On the other hand, nicotine is also very water soluble, so it could have been leached too. The increase in soil total N in loamy sand soil could have been caused by the mineralization, nitrification, and nicotine released in the soils, that inhibited soil bacteria with a role of converting nitrate into the inorganic form and hence N mineralization rate reduced causing an increase of soil total N [5] as the leaching potential is lessened in the loamy sand. Furthermore, an increase of total N in these soils could be a result of released nicotine accumulation to the rhizosphere of which one of its forming components is N. It is likely that the tobacco plant creates a favorable environment for increasing N in the rhizosphere as this nutrient is required for nicotine synthesis.…”

“…The residual levels of other macronutrients, such as Ca and Mg, have not been studied following tobacco production. Recently, investigators have reported an increase in total soil-N levels after tobacco cultivation [4,5], while others have reported a decline in soil macronutrients such as K, P, and S [5][6][7]. The release of nicotine into the rhizosphere was considered to have a major impact on the increase or decrease of these nutrients.…”

“…Even though some studies have reported the tobacco crop to either deplete or increase macronutrients in soils [1,2,4,5], none of these studies have investigated how tobacco plants affect soil chemistry and the levels of macronutrients in different soils [5,7]. Nor has previous research linked leaf nutrient concentrations to these factors.…”

Continuous‐cropping tobacco caused variance of chemical properties and structure of bacterial network in soils

“…Almost all of allelopathic substances are secondary metabolic products, and autotoxic allelopathy caused by allelochemicals is the main reason for continuous‐cropping obstacle (Ren et al, ). Generally, tobacco more easily generates autotoxic allelopathy than other plants (Deng et al, ; Farooq, Hussain, Wakeel, & Cheema, ). For example, the extracts of tobacco rhizosphere soil significantly inhibit tobacco seed germination and negatively influence plant growth and development (Ren et al, ).…”

Temperature dependence of allelopathy duality and its influence on boreal forest succession-A case analysis of Picea schrenkiana

“…The main reason for that is due to the lack of innovative thinking and scientific methods. So far, most filed investigations have mainly focused on phenotypic and morphologic changes of plants (Zuo et al ., 2007; Farooq et al ., 2014), but hardly enter into the allelochemistry of plant secondary metabolites due to the complexity and invisibility. On the other hand, few studies in lab could clearly explain allelopathy in natural settings due to the difficulties in adopting representative samples, simulating geographical climate and ecological environment in the field, indentifying key allelochemicals and quantitatively evaluating allelopathic effects.…”