scholarly journals Developmental Response of Tobacco Plant to Temperature in Relation to Photoperiodic Condition

1956 ◽  
Vol 24 (4) ◽  
pp. 271-274
Author(s):  
Yozo MURAOKA ◽  
Kazunobu Ohori
2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Besma Hamrouni Assadi ◽  
Sabrine Chouikhi ◽  
Refki Ettaib ◽  
Naima Boughalleb M’hamdi ◽  
Mohamed Sadok Belkadhi

Abstract Background The misuse of chemical insecticides has developed the phenomenon of habituation in the whitefly Bemisia tabaci (Gennadius) causing enormous economic losses under geothermal greenhouses in southern Tunisia. Results In order to develop means of biological control appropriate to the conditions of southern Tunisia, the efficacy of the native strain of the predator Nesidiocoris tenuis Reuter (Hemiptera: Miridae) and two entomopathogenic fungi (EPF) Beauveria bassiana and Lecanicillium muscarium was tested against Bemisia tabaci (Gennadius). Indeed, the introduction of N. tenuis in doses of 1, 2, 3, or 4 nymphs per tobacco plant infested by the whitefly led to highly significant reduction in the population of B. tabaci, than the control devoid of predator. The efficacy of N. tenuis was very high against nymphs and adults of B. tabaci at all doses per plant with a rate of 98%. Likewise, B. bassiana and L. muscarium, compared to an untreated control, showed a very significant efficacy against larvae and adults of B. tabaci. In addition, the number of live nymphs of N. tenuis treated directly or introduced on nymphs of B. tabaci treated with the EPF remained relatively high, exceeding 24.8 nymphs per cage compared to the control (28.6). Conclusions It can be concluded that the native strain of N. tenuis and the EPF tested separately were effective against B. tabaci. Their combined use appears to be possible.


Author(s):  
Martin Solanský ◽  
Kamil Mikulášek ◽  
Martina Zapletalová ◽  
Marek Petřivalský ◽  
Annick Chiltz ◽  
...  

Abstract Successful plant defence against microbial pathogens is based on early recognition and fast activation of inducible responses. Key mechanisms include detection of microbe-associated molecular patterns by membrane-localized Pattern Recognition Receptors that induce a basal resistance response. A well-described model of such responses to pathogens involves interaction between Solanaceae plants with proteinaceous elicitors secreted by oomycetes, called elicitins. It has been hypothesised that elicitins' formation of oligomeric structures could be involved in their recognition and activation of defensive transduction cascades. In tests of this hypothesis reported here, using several approaches, we observed differences in tobacco plant responses induced by the elicitin β-cryptogein (β-CRY) and its homodimer (β-CRY DIM). We also found that the C-terminal domain of elicitins of other ELI clades plays a significant role in stabilization of their oligomeric structure and restraint in the cell wall. In addition, covalently crosslinking β-CRY DIM impaired formation of signalling complexes, thereby reducing its capacity to elicit the hypersensitive response and resistance in the host plant, with no significant changes in pathogenesis-related protein expression. The results illuminate the poorly understood role of elicitins' oligomeric structures in oomycetes' interaction with plants, by revealing details of effects of β-CRY dimerization on tobacco plants' recognition and defence responses.


2022 ◽  
pp. 397-420
Author(s):  
Andre F.P. Harahap ◽  
Ahmad Fauzantoro ◽  
Misri Gozan
Keyword(s):  

1940 ◽  
Vol 18 (1) ◽  
pp. 21-34 ◽  
Author(s):  
E Dorothy Ward ◽  
AHK Petrie
Keyword(s):  

Parasitology ◽  
1946 ◽  
Vol 37 (1-2) ◽  
pp. 21-24 ◽  
Author(s):  
Kenneth M. Smith

An account is given of a composite virus disease of tobacco for which the name tobacco rosette has been suggested.The two component viruses, named the mottle and vein-distorting viruses respectively, have been separated, and their symptomatology and methods of transmission described. The mottle virus is both sap and aphis-transmitted, but the vein-distorting virus is aphis-borne only.The symptoms and histopathology of the complex disease in the tobacco plant are dealt with in some detail. There are three main types of symptoms: (1) intense rosetting, (2) splitting of the tissues, (3) formation of enations on the under-surface of the leaves.The splitting of the tissues has been examined microscopically, and a number of photomicrographs are given illustrating the formation of the fissures. It is suggested that there is a concentration of virus in the cambium which prevents the formation of the normal xylem. Abnormal tissue and giant cells are formed in the cortex and pith. This appears to set up stresses which cause the splitting.The insect vector of the complex disease is the aphis Myzus persicae Sulz. Another aphis, M. pseudosolani Theob., is also a vector but is less efficient than M. persicae.The writer's thanks are due to Prof. F. T. Brooks, F.R.S., with whom he discussed the histopathology of the rosette disease, to Dr Roy Markham for taking the photographs illustrating Pl. I, figs. 2–5, and to Mr Charles Harpley of the Molteno Institute for his assistance in taking' the photomicrographs.


2020 ◽  
Vol 7 (01) ◽  
pp. 28-36
Author(s):  
Hayati Minarsih Iskandar ◽  
Sonny Suhandono ◽  
Jembar Pambudi ◽  
Tati Kristianti ◽  
Riza Arief Putranto ◽  
...  

Dehydrin (DHN) is known to play an important role in plant response and adaptation to abiotic stresses (drought, high salinity, cold, heat, etc.). Previous research reported the increased expression of DHN in sugarcane stems exposed to drought stress for 15 days which may be controlled by its corresponding stress inducible promoter. The DHN promoter was succesfully isolated from sugarcane variety PSJT 941 (Pr-1DHNSo) and was cloned to pBI121 expression vector fused to a β-glucuronidase (GUS) reporter gene.  The aim of this research was the functional testing of the Pr-1DHNSo promoter through transformation into tobacco plant treated with in vitro drought stress. Genetic transformation of Pr-1DHNSo construct was conducted by Agrobacterium tumefaciens. The transformed tobacco was then subjected to drought stress treatment using 40% PEG 6000  for five sequential incubations (0, 12, 24, 48 and 72 hours). The GUS assay reveal that the transformed tobacco treated with drought stress showed a blue color denoting GUS activity in leaf, stem and root tissues and this expression increased along with the length of the drought treatment. The analysis of gusA gene using real time-qPCR normalized to the L25 reference gene also showed that the expression increased in line with the length of time of drought stress.  The results presented in this study indicated that the Pr-1DHNSo promoter from sugarcane was expressed and induced by drought stress treatment in tobacco.


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