scholarly journals Chemical Composition of Cuticular Waxes and Pigments and Morphology of Leaves of Quercus suber Trees of Different Provenance

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1165
Author(s):  
Rita Simões ◽  
Ana Rodrigues ◽  
Suzana Ferreira-Dias ◽  
Isabel Miranda ◽  
Helena Pereira

The chemical composition of cuticular waxes and pigments and the morphological features of cork oak (Quercus suber) leaves were determined for six samples with seeds of different geographical origins covering the natural distribution of the species. The leaves of all samples exhibited a hard texture and oval shape with a dark green colour on the hairless adaxial surface, while the abaxial surface was lighter, with numerous stomata and densely covered with trichomes in the form of stellate multicellular hairs. The results suggest an adaptive role of leaf features among samples of different provenance and the potential role of such variability in dealing with varying temperatures and rainfall regimes through local adaptation and phenotypic plasticity, as was seen in the trial site, since no significant differences in leaf traits among the various specimens were found, for example, specific leaf area 55.6–67.8 cm2/g, leaf size 4.6–6.8 cm2 and photosynthetic pigment (total chlorophyll, 31.8–40.4 µg/cm2). The leaves showed a substantial cuticular wax layer (154.3–235.1 µg/cm2) composed predominantly of triterpenes and aliphatic compounds (61–72% and 17–23% of the identified compounds, respectively) that contributed to forming a nearly impermeable membrane that helps the plant cope with drought conditions. These characteristics are related to the species and did not differ among trees of different seed origin. The major identified compound was lupeol, indicating that cork oak leaves may be considered as a potential source of this bioactive compound.

1997 ◽  
Vol 75 (5) ◽  
pp. 769-780 ◽  
Author(s):  
Dolors Verdaguer ◽  
Marisa Molinas

The endodermis maturation process was studied in the primary root of the cork oak (Quercus suber L.) with emphasis on the chemical nature of the cell wall and on the possible role of tannins. Tannins were found in endodermal and adjacent cortical cells in all maturation stages. We discuss our findings in relation to the previous literature in other woody and herbaceous species. The results of the histochemical tests showed differences in the aliphatic compounds of the suberin between the Casparian strip suberin and the suberin layer deposited in state II cells. Plasmodesmata were present in radial and tangential walls during the entire maturation process. The significance of plasmodesmata and of the suberin deposition pattern is discussed in relation to apoplastic and symplastic transport in roots. Key words: Casparian strip, endodermis, primary root, suberin, Quercus suber L.


2019 ◽  
Vol 42 (3) ◽  
pp. 251-257
Author(s):  
Luis A. Hernández-Alvarado ◽  
Esaú Ruiz-Sánchez ◽  
Luis Latournerie-Moreno ◽  
René Garruña-Hernández ◽  
Daniel González-Mendoza ◽  
...  

Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is one of the most damaging pests of Capsicum annuum L. (Solanales: Solanaceae) worldwide. The large genetic diversity of landrace genotypes of C. annuum in several regions of America offers an excellent opportunity to study the factors involved in the resistance response to B. tabaci. This study was carried out to evaluate the oviposition preference and nymphal mortality of B. tabaci in landrace genotypes of C. annuum and to determine whether the physical or chemical characteristics of the leaves influence this response. Oviposition preference varied among genotypes. Low oviposition preference and high nymphal mortality were observed in genotypes Amaxito and Simojovel. Oviposition preference and nymphal mortality showed no significant correlation with leaf size, leaf hardness or trichome density. The chemical composition analyses of leaves of four genotypes with differential response on nymphal mortality showed significant differences in the foliar content of N, phenol, and total flavonoids, but there was no clear trend in the association between the nymphal mortality and chemical composition of leaves.


Synlett ◽  
2021 ◽  
Author(s):  
Kripa Subramanian ◽  
Subhash L. Yedage ◽  
Kashish Sethi ◽  
Bhalchandra M. Bhanage

An electrochemical method for the synthesis of phenanthridinones via constant potential electrolysis (CPE) mediated by <i>n</i>-Bu<sub>4</sub>NI (TBAI) has been reported. The protocol is metal and oxidant free and proceeds with 100% current efficiency. Here TBAI plays the dual role of the redox catalyst as well as supporting electrolyte. The intramolecular C-H activation proceeds under mild reaction conditions and short reaction time via electrochemically generated amidyl radicals. The reaction has been scaled up to gram level showing its practicability and the synthetic utility and applicability of the protocol has been demonstrated by the direct one-step synthesis of the bioactive compound Phenaglaydon.


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