Nanoscale sulfur can be a multifunctional agricultural
amendment
to enhance crop nutrition and suppress disease. Pristine (nS) and
stearic acid coated (cS) sulfur nanoparticles were added to soil planted
with tomatoes (Solanum lycopersicum) at 200 mg/L
soil and infested with Fusarium oxysporum. Bulk sulfur,
ionic sulfate, and healthy controls were included. Orthogonal end
points were measured in two greenhouse experiments, including agronomic
and photosynthetic parameters, disease severity/suppression, mechanistic
biochemical and molecular end points including the time-dependent
expression of 13 genes related to two S bioassimilation and pathogenesis-response,
and metabolomic profiles. Disease reduced the plant biomass by up
to 87%, but nS and cS amendment significantly reduced disease as determined
by area-under-the-disease-progress curve by 54 and 56%, respectively.
An increase in planta S accumulation was evident,
with size-specific translocation ratios suggesting different uptake
mechanisms. In vivo two-photon microscopy and time-dependent gene
expression revealed a nanoscale-specific elemental S bioassimilation
pathway within the plant that is separate from traditional sulfate
accumulation. These findings correlate well with time-dependent metabolomic
profiling, which exhibited increased disease resistance and plant
immunity related metabolites only with nanoscale treatment. The linked
gene expression and metabolomics data demonstrate a time-sensitive
physiological window where nanoscale stimulation of plant immunity
will be effective. These findings provide mechanistic understandings
of nonmetal nanomaterial-based suppression of plant disease and significantly
advance sustainable nanoenabled agricultural strategies to increase
food production.
Summary
Understanding the resilience of moist tropical forests to treefall disturbance events is important for understanding the mechanisms that underlie species coexistence and for predicting the future composition of these ecosystems. Here, we test whether variation in the functional composition of Amazonian forests determines their resilience to disturbance.We studied the legacy of natural treefall disturbance events in four forests across Amazonia that differ substantially in functional composition. We compared the composition and diversity of all free‐standing woody stems 2–10 cm diameter in previously disturbed and undisturbed 20 × 20 m subplots within 55, one‐hectare, long‐term forest inventory plots.Overall, stem number increased following disturbance, and species and functional composition shifted to favour light‐wooded, small‐seeded taxa. Alpha‐diversity increased, but beta‐diversity was unaffected by disturbance, in all four forests.Changes in response to disturbance in both functional composition and alpha‐diversity were, however, small (2 – 4% depending on the parameter) and similar among forests.
Synthesis. This study demonstrates that variation in the functional composition of Amazonian forests does not lead to large differences in the response of these forests to treefall disturbances, and overall, these events have a minor role in maintaining the diversity of these ecosystems.
This study with the Gardner-Eberhart model (1966) involved eight maize parental populations and their related populations. The objectives were to estimate the cumulative gene effects (additive, dominance and heterotic) which could The justify support of a maize hybrid programo The grain yield inter-varietal dominance effects accounted for 55.54% of the generation means, suggesting large genetic variability within populations. Heterotic effects accounted for 12.11 %, indicating little difference in gene frequency for loci controlling grain yield. Plant height followed the same pattero as grain yield, since dominance effects were the most important. However, homozygote loci (aj) were important in explaining genetic variability for days to bloom and number of ears. For grain yield, the cross Pop. 32 x Pop. 21 maximized the heterotic effects. Population 21 exhibited a high average heterosis, so we suspect that its, combination with Popo 32 and CN(S)-C3, among others, would be a great genetic material for a Reciprocal Recurrent Selection Programo
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