A New Oidiodendron maius Strain Isolated from Rhododendron fortunei and its Effects on Nitrogen Uptake and Plant Growth

Abstract Soil salinity with different harmful effects on plant growth and productivity is one of the main reasons in diminishing biological nitrogen fixation and nitrogen assimilation in legume plants. Molybdate has a key role on nitrogen metabolism of plants and can be has a beneficial effect on it. Thus, this experiment was conducted to evaluate the effects of sodium molybdate spraying (0.2 and 0.4% solutions in water) on nodulation, nitrogen uptake and translocation in soybean plants under different levels of salt stress (0, 5 and 10 dS m−1 NaCl, respectively). Salinity reduced the nodulation, root and shoot growth and special flavonoids content in roots, which are have a key role in nodulation includes, daidzein, genistein, coumestrol and glycitein, also diminished nitrogenase, glutamine synthetase (GS), glutamate dehydrogenase (GDH), glutamine oxoglutarate aminotransferase (GOGAT) and nitrate reductase (NR) activities in nodes, nitrogen content of nodes, roots and leaves, nitrogen uptake and translocation by soybean plants. Under salt stress and nonsaline condition, sodium molybdate treatments improved the nodulation by increasing flavonoids content of roots, also these treatments enhanced the plant growth and nitrogenase, GS, GDH, GOGAT and NR activities of nodes. Furthermore, nitrogen content of nodes, roots and leaves, nitrogen uptake and translocation by soybean plants improved by sodium molybdate applications. Both of the sodium molybdate doses, exposed the similar effects on improving nodulation and nitrogen metabolism of soybean.

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Evaluating RGB Imaging and Multispectral Active and Hyperspectral Passive Sensing for Assessing Early Plant Vigor in Winter Wheat

Sensors ◽

10.3390/s18092931 ◽

2018 ◽

Vol 18 (9) ◽

pp. 2931 ◽

Cited By ~ 9

Author(s):

Lukas Prey ◽

Malte von Bloh ◽

Urs Schmidhalter

Keyword(s):

Plant Growth ◽

Nitrogen Uptake ◽

Low Cost ◽

Canopy Cover ◽

Dry Weight ◽

Early Growth ◽

Spectral Unmixing ◽

Growth Stages ◽

Plant Vigor ◽

Red Edge

Plant vigor is an important trait of field crops at early growth stages, influencing weed suppression, nutrient and water use efficiency and plant growth. High-throughput techniques for its evaluation are required and are promising for nutrient management in early growth stages and for detecting promising breeding material in plant phenotyping. However, spectral sensing for assessing early plant vigor in crops is limited by the strong soil background reflection. Digital imaging may provide a low-cost, easy-to-use alternative. Therefore, image segmentation for retrieving canopy cover was applied in a trial with three cultivars of winter wheat (Triticum aestivum L.) grown under two nitrogen regimes and in three sowing densities during four early plant growth stages (Zadok’s stages 14–32) in 2017. Imaging-based canopy cover was tested in correlation analysis for estimating dry weight, nitrogen uptake and nitrogen content. An active Greenseeker sensor and various established and newly developed vegetation indices and spectral unmixing from a passive hyperspectral spectrometer were used as alternative approaches and additionally tested for retrieving canopy cover. Before tillering (until Zadok’s stage 20), correlation coefficients for dry weight and nitrogen uptake with canopy cover strongly exceeded all other methods and remained on higher levels (R² > 0.60***) than from the Greenseeker measurements until tillering. From early tillering on, red edge based indices such as the NDRE and a newly extracted normalized difference index (736 nm; ~794 nm) were identified as best spectral methods for both traits whereas the Greenseeker and spectral unmixing correlated best with canopy cover. RGB-segmentation could be used as simple low-cost approach for very early growth stages until early tillering whereas the application of multispectral sensors should consider red edge bands for subsequent stages.

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