5 research outputs found
Constituents leached by tomato seeds regulate the behavior of root-knot nematodes and their antifungal effects against seed-borne fungi
Germinating seeds can release diverse phytochemicals that repel, inhibit, or kill pathogens such as root-knot nematodes and seed-borne fungi. However, little is known about the composition of these phytochemicals and their effects on pathogens. In this study, we demonstrated that tomato seed exudates can attract the nematode Meloidogyne incognita using a dual-choice assay. Eighteen compounds were then isolated and identified from the exudates. Of these, esters (1-3), fatty acids (4-6), and phenolic acids (10-12) were proven to be the signaling molecules that facilitated the host-seeking process of second-stage juveniles (J2s) of nematodes, while alkaloids (17 and 18) disrupted J2s in locating their host. Furthermore, some phenolic acids and alkaloids showed antifungal effects against seed-borne fungi. In particular, ferulic acid (12) showed obvious activity against Aspergillus flavus (minimum inhibitory concentration (MIC), 32 μg/mL), while dihydrocapsaicin (17) showed noticeable activity against Fusarium oxysporum (MIC, 16 μg/mL). Overall, this study presents the first evidence that M. incognita can be attracted to or deterred by various compounds in seed exudates through identification of the structures of the compounds in the exudates and analysis of their effects on nematodes. Furthermore, some antifungal compounds were also found. The findings of this work suggest that seed exudates are new source for finding insights into the development of plant protective substances with nematocidal and antifungal effects
Solution-Processed Organic Thin-Film Transistor Arrays with the Assistance of Laser Ablation
Importance of Solvent Removal Rate on the Morphology and Device Performance of Organic Photovoltaics with Solvent Annealing
Solvent vapor annealing
has been widely used in organic photovoltaics (OPV) to tune the morphology
of bulk heterojunction active layer for the improvement of device
performance. Unfortunately, the effect of solvent removal rate (SRR)
after solvent annealing, which is one of the key factors that impact
resultant morphology, on the morphology and device performance of
OPV has never been reported. In this work, the nanoscale morphology
of small molecule (SM):fullerene bulk heterojunction (BHJ) solar cell
from different SRRs after solvent annealing was examined by small-angle
neutron scattering and grazing incidence X-ray scattering. The results
clearly demonstrate that the nanoscale morphology of SM:fullerene
BHJ especially fullerene phase separation and concentration of fullerene
in noncrystalline SM was significantly impacted by the SRR. The enhanced
fullerene phase separation was found with a decrease of SRR, while
the crystallinity and molecular packing of SM remained unchanged.
Correlation to device performance shows that the balance between pure
fullerene phase and mixing phase of SM and fullerene is crucial for
the optimization of morphology and enhancement of device performance.
Moreover, the specific interfacial area between pure fullerene phase
and mixing phase is crucial for the electron transport and thus device
performance. More importantly, this finding would provide a more careful
and precise control of morphology of SM:fullerene BHJ and offers a
guideline for further improvement of device performance with solvent
annealing
Impact of Fullerene Structure on Nanoscale Morphology and Miscibility and Correlation of Performance on Small Molecules: Fullerene Solar Cell
This manuscript reports the impact
of fullerene structure on the
morphology and miscibility of small molecules via a fullerene bulk
heterojunction solar cell. The small angle neutron scattering and
neutron reflectometry measurements were analyzed to provide quantifiable
measures of the morphology of the resultant mixtures, offering miscibility,
domain sizes, interfacial area between the small molecule and fullerene,
and depth profiles in the mixtures. These results indicate that the
bis-adduct fullerenes exhibit lower miscibility in small molecules.
Correlation of miscibility and morphology to photovoltaic properties
indicates that small molecule/fullerene miscibility is crucial to
rationally optimize the design of fullerenes for use in small molecule
organic photovoltaics. A higher open circuit voltage was obtained
for bis-adduct fullerene devices which, however, does not translate
to an increased power conversion efficiency. This decrease in performance
is associated with the lower miscibility of bis-fullerene, which decreases
the probability of the dissociation of excitons and enhances charge
recombination rate in the miscible region. A quantitative analysis
shows that an increase in the average separation of fullerenes in
the miscible region is detrimental to electron transport in the miscible
region, especially for a distance greater than ∼11 Å