scholarly journals Nitrogen Fixation Outside and Inside Plant Tissues

Author(s):  
C.P. Chanway ◽  
R. Anand ◽  
H. Yang
PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9062
Author(s):  
Yongbin Li ◽  
Qin Li ◽  
Guohua Guan ◽  
Sanfeng Chen

Phosphate (P) availability often limits biological nitrogen fixation (BNF) by diazotrophic bacteria. In soil, only 0.1% of the total P is available for plant uptake. P solubilizing bacteria can convert insoluble P to plant-available soluble P (ionic P and low molecular-weight organic P). However, limited information is available about the effects of synergistic application of diazotrophic bacteria and P solubilizing bacteria on the nitrogenase activity of rhizosphere and nifH expression of endosphere. In this study, we investigated the effects of co-inoculation with a diazotrophic bacterium (Paenibacillus beijingensis BJ-18) and a P-solubilizing bacterium (Paenibacillus sp. B1) on wheat growth, plant and soil total N, plant total P, soil available P, soil nitrogenase activity and the relative expression of nifH in plant tissues. Co-inoculation significantly increased plant biomass (length, fresh and dry weight) and plant N content (root: 27%, shoot: 30%) and P content (root: 63%, shoot: 30%). Co-inoculation also significantly increased soil total N (12%), available P (9%) and nitrogenase activity (69%) compared to P. beijingensis BJ-18 inoculation alone. Quantitative real-time PCR analysis showed co-inoculation doubled expression of nifH genes in shoots and roots. Soil nitrogenase activity and nifH expression within plant tissues correlated with P content of soil and plant tissues, which suggests solubilization of P by Paenibacillus sp. B1 increased N fixation in soils and the endosphere. In conclusion, P solubilizing bacteria generally improved soil available P and plant P uptake, and considerably stimulated BNF in the rhizosphere and endosphere of wheat seedlings.


Author(s):  
Ocampo-Guevara Jhon-Alexander ◽  
Vega Espinoz Johana Jazmín ◽  
Rivera González Johanna Rivera ◽  
Carlos Jacome

Agribusiness is one of the areas with the greatest impact, which, due to the processes involved within this area, generates waste that, given its composition, is used in optimal materials to be used for degradation methods in the production of composting, different microorganisms such as Pseudomonas, Bacillus, Aspergillus help in the decomposition of waste from agribusiness, the metabolic activity of these microorganisms allows the degradation of animal and plant tissues such as cellulose, starch, pectin, proteins, agar that intervene in nitrification and nitrogen fixation processes, for the degradation process it is necessary to carry out in composting beds of organic waste isolated with strains of the rhizosphere from the natural forest of CIPCA the strains use the dimensions of 4 x 1 x 1 giving a city layer of 4𝑚3 or about 640 kg of organic rough which are covered with geo mucosa, surrounded by gutters to collect leachate two produced by the effect of degradation, this process of degradation of organic matter allows to obtain a product with characteristics such as earthy odor, texture and uniform structure, where a pH close to neutral was registered in the control beds, gradually increasing from that moment with slightly alkaline values where it does not present characteristics of the initial organic matter, reducing the volume by 35%, for this the objective is to maintain Controller of certain parameters of temperature, humidity, pH, compost ratio and organic matter content.


Author(s):  
John S. Gardner ◽  
W. M. Hess

Powdery mildews are characterized by the appearance of spots or patches of a white to grayish, powdery, mildewy growth on plant tissues, entire leaves or other organs. Ervsiphe cichoracearum, the powdery mildew of cucurbits is among the most serious parasites, and the most common. The conidia are formed similar to the process described for Ervsiphe graminis by Cole and Samson. Theconidial chains mature basipetally from a short, conidiophore mother-cell at the base of the fertile hypha which arises holoblastically from the conidiophore. During early development it probably elongates by polar-tip growth like a vegetative hypha. A septum forms just above the conidiophore apex. Additional septa develop in acropetal succession. However, the conidia of E. cichoracearum are more doliform than condia from E. graminis. The purpose of these investigations was to use scanning electron microscopy (SEM) to demonstrate the nature of hyphal growth and conidial formation of E. cichoracearum on field-grown squash leaves.


Author(s):  
Y. R. Chen ◽  
Y. F. Huang ◽  
W. S. Chen

Acid phosphatases are widely distributed in different tisssues of various plants. Studies on subcellular localization of acid phosphatases show they might be present in cell wall, plasma lemma, mitochondria, plastid, vacuole and nucleus. However, their localization in rice cell varies with developmental stages of cells and plant tissues. In present study, acid phosphatases occurring in root cap are examined.Sliced root tips of ten-day-old rice(Oryza sativa) seedlings were fixed in 0.1M cacodylate buffer containing 2.5% glutaraldehyde for 2h, washed overnight in same buffer solution, incubated in Gomori's solution at 37° C for 90min, post-fixed in OsO4, dehydrated in ethanol series and finally embeded in Spurr's resin. Sections were doubly stained with uranyl acetate and lead citrate, and observed under Hitachi H-600 at 75 KV.


Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


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