Physiological and Biochemical Mechanism of Allelopathy of Secalonic Acid F on Higher Plants

2001 ◽  
Vol 93 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Ren Sen Zeng ◽  
Shi Ming Luo ◽  
Yue Hong Shi ◽  
Mu Biao Shi ◽  
Cong Yong Tu
2012 ◽  
Vol 518-523 ◽  
pp. 5363-5365
Author(s):  
Guo Fu He ◽  
Juan Li ◽  
Wei Liu ◽  
Jing Li Du

In order to ascertain the allelopathy of Reed on Alligator Weed, the water culture experiments were performed to investigate the effects of aqueous extract on the growth, physiological and biochemical mechanism in Alligator Weed. The results showed that aqueous extract of Reed inhibited the growth of Alligator Weed, and the inhibition became stronger as the concentration of the extract increased. Some results from physiological and biochemical mechanism of treated Alligator Weed indicated that with the increase of extract concentration, photosynthetic pigment contents, root activity and CAT activity decreased, while P and MDA contents increased; N content decreased first and then up to normal. The results showed that aqueous extract of Reed inhibited the photosynthesis, CAT activities of Alligator Weed but increased the MDA content of Alligator Weed.


1994 ◽  
Author(s):  
John Steffens ◽  
Eithan Harel ◽  
Alfred Mayer

Polyphenol oxidase (PPO) catalyzes the oxidation of phenols to quinones at the expense of O2. PPOs are ubiquitous in higer plants, and their role in oxidative browning of plant tissues causes large annual losses to food production. Despite the importance of PPOs to agriculture, the function(s) of PPOs in higher plants are not understood. Among other roles, PPOs have been proposed to participate in aspects of chloroplast metabolism, based on their occurrence in plastids and high Km for O2. Due to the ability of PPO to catalyze formation of highly reactive quinones, PPOs have also been proposed to be involved in a wide array of defensive interactions with insect, bacterial, and fungal pests. Physiological and biochemical studies of PPO have provided few answers to the major problems of PPO function, subcellular localization, and biochemical properties. This proposal achieved the following major objectives: cloning of PPO cDNAs in potato and tomato; characterization of the tomato PPO gene family; antisense downregulation of the tomato PPO gene family; and reduction in post-harvest enzymic browning of potato through expression of antisense PPO genes under the control of tuber-specific promoters. In addition, we established the lumenal localization of PPO, characterized and clarified the means by which PPOs are imported and processed by chloroplasts, and provided insight into the factors which control localization of PPOs. This proposal has thereby provided fundamental advances in the understanding of this enzyme and the control of its expression.


1997 ◽  
Vol 160 (2) ◽  
pp. 239-251 ◽  
Author(s):  
Jóska Gerendás ◽  
Zhujun Zhu ◽  
Roy Bendixen ◽  
R. George Ratcliffe ◽  
Burkhard Sattelmacher

2021 ◽  
pp. 180-187
Author(s):  
I. Beznosko ◽  
A. Parfenyuk ◽  
T. Gorgan ◽  
L. Gavrilyuk ◽  
Y. Turovnik

Mycobiota of Podolyanka and Poliska 90 winter wheat varieties seeds was found to be represented mainly by fungi of the Alternaria, Fusarium, Penicillium, Aspergillus, Chaetomium, Trichothecium genera which are characterized by various levels of pathogenicity, depending on the physiological and biochemical properties the host variety. Signifcant increase is air temperature and relative humidity during the wheat flowering and milking stage of grain ripening contributed to the spread of micromycetes of the genus Alternaria Nees. (50 %). The seeds the affected by fungi Alternaria were physiologically underdeveloped, had low energy and germination, which averaged 40 %. Plants form such seeds lag behind in growth and development. It is established that the physiological and biochemical mechanism of Podolyanka winter wheat variety stimulates mycelium radial growth and intensity of fungi Alternaria sporulation indicating the rapid reproduction of micromycetes, which contributes to the contamination of agrophytocenoses by propagative structures of the pathogen. However, the intensity of spore formation and the rate of mycelium radial growth on Poliska 90 variety seeds, was signifcantly lower. This fact gives reason to believe that the physiological and biochemical mechanism of the Poliska 90 variety plants is able to restrain the intensity of the genus Alternaria micromycetes spore formation at an ecologically safe level. It was found that the seeds of the Podolyanka and Poliska 90 winter wheat varieties are low in protein content and have high humidity. In terms of raw gluten content, they are classifed in the quality group 3. Isolates of fungi the genus Alternaria developed more intensively on the Podolyanka winter wheat variety grain, which is characterized by a lower content of protein and gluten. However the development of fungi was signifcantly lower on the Poliska 90 variety grain, which is characterized by a slightly higher content of protein and gluten. System-ecological approach to the improvement of agroecosystems in organic farming can be carried out using indicators of the variety physiological and biochemical properties interaction with physiological properties of phytopathogenic fungi, namely sporulation intensity and mycelial radial growth rate. This can increase the level of biosafety in agroecosystems and improve the quality of plant raw materials. Key words: the frequency of occurrence, mycelium radial growth, sporulation intensity, phytosanitary optimization, wheat winter agrphytocenoses.


Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.


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