Fungal elicitor-induced retardation and its restoration of root growth in tobacco seedlings

2011 ◽  
Vol 66 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Yoshio Kawaguchi ◽  
Takumi Nishiuchi ◽  
Hiraoki Kodama ◽  
Toshitsugu Nakano ◽  
Kazuma Nishimura ◽  
...  
2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Renata Biba ◽  
Mirta Tkalec ◽  
Petra Cvjetko ◽  
Petra Peharec Štefanić ◽  
Sandra Šikić ◽  
...  

Extensive commercialization of silver nanoparticles (AgNPs) raises the risk of their accumulation in the soil-plant system. Once released into the environment, AgNPs are prone to chemical transformations, which makes it hard to determine whether their phytotoxic effects are purely NP-related or a consequence of released Ag+ ions. In this study the effects of 25, 50, 75, 100 and 150 μM AgNPs and AgNO3 on seed germination and early growth of tobacco (Nicotiana tabacum L.) seedlings were compared. Additionally, the effect on photosynthetic performance and pigment content were investigated. Germination rate and index values indicated delayed and slower germination in some AgNP treatments. Lower AgNP concentrations stimulated root growth, but induced prominent reduction in fresh weight. Contrary, all AgNO3 concentrations inhibited root growth but only the higher ones decreased fresh weight. Obtained results imply that the observed AgNP toxicity could be ascribed to NP form and can be correlated with high AgNP stability in the solid medium. On the other hand, majority of AgNP and AgNO3 treatments induced an increase in chlorophyll content which was accompanied with significantly lower values of relative electron transport rate and coefficient of photochemical quenching, implying an inhibition of the electron transport chain. Similar impact of AgNPs and AgNO3 on photosynthesis can be correlated with lower stability of AgNPs in the liquid medium, resulting in AgNP aggregation and dissolution of Ag+ ions.


1994 ◽  
Vol 92 (4) ◽  
pp. 675-680 ◽  
Author(s):  
Iduna Arduini ◽  
Douglas L. Godbold ◽  
Antonino Onnis

Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum


2005 ◽  
Vol 33 (4) ◽  
pp. 697-704 ◽  
Author(s):  
Adriana Sánchez-Urdaneta ◽  
Cecilia Peña-Valdivia ◽  
Carlos Trejo ◽  
J. Aguirre R. ◽  
Elizabeth Cárdenas S.

2013 ◽  
Vol 12 (10) ◽  
pp. 695-701
Author(s):  
Herve Martial Poumale Poumale ◽  
Alphonsine Nkapwa Guedem ◽  
Louis Pergaud Sandjo ◽  
Bonaventure Tchaleu Ngadjui ◽  
Yoshihito Shiono

A new lupane type triterpene (1), together with betulinic acid (2), friedelin (3), aristolochic acid I (4), alpinumisoflavone (5) and 4’-O-methylepinumisoflavone (6) have been isolated from the leaves of Thecacoris annobonea. The structure of the new compound was elucidated on the basis of 1 and 2D NMR experiments. The isolated compounds were evaluated for their phytotoxicity and antimicrobial activity. 1 exhibited significant antimicrobial activity at 30 μg/ml and compounds 1, 2, 3, 4, 5 and 6 inhibited root growth lettuce at 100 μg/ml. 


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