scholarly journals Death of pastures syndrome: tissue changes in Urochloa hybrida cv. Mulato II and Urochloa brizantha cv. Marandu

2017 ◽  
Vol 77 (1) ◽  
pp. 97-107 ◽  
Author(s):  
N. G. Ribeiro-Júnior ◽  
A. P. R. Ariano ◽  
I. V. Silva
Keyword(s):  
Anatomical Study ◽  
Sieve Tube ◽  
Cortical Region ◽  
Forage Production ◽  
Aerenchyma Formation ◽  
Mato Grosso ◽  
Vessel Elements ◽  
Tissue Changes ◽  
Urochloa Brizantha ◽  
The Individual

Abstract The quality of forage production is a prerequisite to raising livestock. Therefore, income losses in this activity, primarily cattle raising, can result in the impossibility of economic activity. Through the qualitative and quantitative anatomical study of Urochloa hybrida cv. Mulato II and U. brizantha cv. Marandu, we searched for descriptions and compared changes in the individual vegetative body from populations with death syndrome pastures (DPS). Specimens were collected at different physiological stages from farms in northern Mato Grosso. After collection, the individuals were fixed in FAA50 and stored in 70% alcohol. Histological slides were prepared from the middle third of the sections of roots, rhizomes, and leaves, and the proportions and characteristics of tissues were evaluated in healthy, intermediate, and advanced stages of DPS. Changes were compared between cultivars. With the advancement of the syndrome, the following changes were observed: a more marked decrease in the length of roots in U. hybrida; disorganization of the cortical region of the roots and rhizome cultivars; fungal hyphae in roots and aerenchyma formation in U. hybrida; a decrease in sclerenchyma fiber proportions in roots and leaves; sclerification of the epidermis of U. brizantha rhizomes; and an increase in pericyclic fibers in U. hybrida. Furthermore, there was a decrease in the volume of epidermal cells of the abaxial face of the leaves of both cultivars, with a greater reduction in U. hybrida; a gradual decrease in thickness in the midrib of leaves similar to leaf mesophyll; conduction system obstructions; partial or total cell lysis in roots and rhizomes affected by the syndrome. Obstructions in sieve tube element and companion cells, and sometimes obstruction in xylem vessel elements. The evolution of DPS in cultivars was similar, but there were variations, arising probably from the physiological response to stress, such as aerenchyma formation in the root and increased pericycle in the rhizome of U. hybrida.

scholarly journals Size correlations among cambial initials and their derivatives in Polyalthia longifolia Thw.

2015 ◽  
Vol 48 (1) ◽  
pp. 93-98 ◽  
Author(s):  
D. D. Sharma ◽  
H. K. Sharma ◽  
G. S. Paliwal
Keyword(s):  
Major Change ◽  
Sieve Tube ◽  
Maximum Increase ◽  
Vessel Elements ◽  
Parenchyma Cells ◽  
Fusiform Initials ◽  
The Individual ◽  
Average Size ◽  
Mother Cells ◽  
Polyalthia Longifolia

The length and breadth of the cambial initials and their derivatives have been examined in <i>Polyalthia longifolia</i>, a tropical tree possessing non-storied cambium. Taking the average size of the initials and the elements originating from them, most of the sieve-tube elements have been found to be slightly shorter in length than the fusiform initials. On the other hand, a few of these are still shorter - almost half of the fusiform initials, due to transverse or somewhat oblique divisions in the sieve element mother cells. The vessel elements are slightly shorter but 5-6 times wider than the fusiform initials. The parenchyma strands, in phloem comprising cells storing starch or tannin (pps), in xylem accumulating starch only (ssps), are more or less equal to fusiform initials indicating that the xylem and phloem mother cells forming parenchyma cells have not undergone any major change except for transverse divisions. The individual vessel-associated parenchyma cells (v.a.p. cells) are wider but much shorter in length as compared to the starch-storing parenchyma cells (s.s.p. cells) indicating that more transverse divisions have occured in the strands of the former than those of the latter. Among all the cambial derivatives, the fibers exhibit maximum increase in length, due to intrusive growth. The ray parenchyma cells are slightly longer than the ray initials possibly due to the elongation of these initials during their transformation into vascular ray cells.

Productivity increase, reduction of nitrogen fertiliser use and drought-stress mitigation by inoculation of Marandu grass (Urochloa brizantha) with Azospirillum brasilense

2019 ◽  
Vol 70 (1) ◽  
pp. 61 ◽  
Author(s):  
Rubson da C. Leite ◽  
José G. D. dos Santos ◽  
Eduardo L. Silva ◽  
Cássio R. C. R. Alves ◽  
Mariangela Hungria ◽  
...  
Keyword(s):  
Drought Stress ◽  
South America ◽  
Central Region ◽  
Azospirillum Brasilense ◽  
Forage Production ◽  
Nitrogen Fertiliser ◽  
Forage Species ◽  
Productivity Increase ◽  
Urochloa Brizantha ◽  
Fertiliser Use

Among the forage species cultivated in South America, the genus Urochloa is the most used, and the cultivar Marandu of U. brizantha is the most widely planted in Brazil. The objective of this study was to evaluate forage performance in association with Azospirillum brasilense, combined with nitrogen (N) fertilisation. The study was conducted under field conditions in Araguaína, Tocantins, in the central region of Brazil, between March 2016 and March 2017. Four N fertiliser rates (0, 12.5, 25 and 50kg/ha of N per cutting cycle) were combined with two inoculation treatments (inoculated and non-inoculated), with evaluations carried out in three periods of the year (transition, dry and wet seasons). Marandu grass plants inoculated with A. brasilense had greater plant height, number of tillers and forage production than non-inoculated plants, regardless of the N rate. Inoculation with A. brasilense allowed a 20% reduction in N fertilisation. Our results indicate that inoculation with A. brasilense in Marandu grass, as well as increasing forage production, can help to mitigate the stresses caused by the dry season.

scholarly journals Soil quality and soybean productivity in crop-livestock integrated system in no-tillage

2018 ◽  
Vol 53 (11) ◽  
pp. 1248-1258 ◽  
Author(s):  
Jackeline Vieira dos Santos Laroca ◽  
Juliana Mendes Andrade de Souza ◽  
Gabriela Castro Pires ◽  
Gleidson José Coutinho Pires ◽  
Leandro Pereira Pacheco ◽  
...  
Keyword(s):  
Soil Quality ◽  
Block Design ◽  
Pigeon Pea ◽  
Integrated System ◽  
Total N ◽  
Mato Grosso ◽  
Positive Effects ◽  
Urease Enzyme ◽  
Urochloa Brizantha ◽  
Management Changes

Abstract: The objective of this work was to evaluate the quality of the soil and its relation with soybean (Glycine max) yield in an integrated crop-livestock system (ICLS), with intercropping between grasses and legumes in the pasture phase. The experiment was carried out in the state of Mato Grosso, Brazil, on a dystrophic Oxisol, in which grasses (Megathyrsus maximus 'BRS Tamani' and Urochloa brizantha 'BRS Piatã'), intercropped with cowpea (Vigna unguiculata 'BRS Tumucumaque') and pigeon pea (Cajanus cajan 'BRS Mandarim'), were cultivated after soybean harvest. A randomized complete block design was used, with three replicates, in a split-plot arrangement, in which grasses were considered as plots, and legumes as subplots. Legume intercrops provided increases of C and total N stocks. The intercrops caused the increase of C and N of the microbial biomass, whereas the single cultures contributed to stress in the soil microbiota. The activity of the urease enzyme was sensitive to management changes in the short term, but acid phosphatase and β-glucosidase were poorly sensitive indicators. Soil quality is high with intercropping between grasses and legumes, with positive effects on soybean grain yield.

scholarly journals RADIAL GROWTH DYNAMICS OF Khaya ivorensis TREES FROM EXPERIMENTAL PLANTATION

2018 ◽  
Vol 42 (2) ◽  
Author(s):  
Denise Ransolin Soranso ◽  
Graziela Baptista Vidaurre ◽  
Matheus Peres Chagas ◽  
José Tarcísio da Silva Oliveira ◽  
João Gabriel Missia da Silva ◽  
...  
Keyword(s):  
Growth Dynamics ◽  
Anatomical Study ◽  
Radial Increment ◽  
Growth Rings ◽  
African Mahogany ◽  
False Rings ◽  
Biological Adaptation ◽  
Historical Series ◽  
Vessel Elements ◽  
Scanned Images

ABSTRACT The objective of this study was to characterize the formation of growth rings in Khaya ivorensis wood, as well as to analyze the variation in the morphology of the vessel elements, aiming to understand the growth of this species in experimental plantations. Disks from the bases of five trees were collected, and after polishing the cross-section, demarcation of the growth rings limits was carried out. The anatomical study of the wood was conducted with the purpose of characterizing the rings, and their width was measured by means of scanned images of the disks. A historical series of data was obtained concerning the diameter of the trees to establish a correlation with the width of the rings measured over the years. The growth rings limits of African mahogany wood are demarcated by a thin layer of marginal parenchyma, and the presence of false rings has been observed. Significant annual growth correlation of 0.62 was observed among the trees, being the radial increment of irregular wood in the first years (wide and narrow rings), and highlighting the 3rd and 11th year of growth in which the largest increases were observed due to a biological adaptation tendency to the environment and the occurrence of thinning carried out in the planting area, respectively.

Comparative Structure Of Vascular Cambium And Its Derivatives In Some Species Of Sterculia

IAWA Journal ◽  
1996 ◽  
Vol 17 (3) ◽  
pp. 311-318 ◽  
Author(s):  
K. S. Rao ◽  
Kishore S. Rajput ◽  
T. Srinivas
Keyword(s):  
Sieve Tube ◽  
Vascular Cambium ◽  
The South ◽  
Structural Variations ◽  
Axial Parenchyma ◽  
Vessel Elements ◽  
Comparative Structure ◽  
The Mean ◽  
Cambial Cells ◽  
Sheath Cells

Structural variations in cambium, xylem and phloem collected from main trunks of Sterculia colorata, S. alata, S. villosa, S. urens and S. foetida growing in the South Dangs forests were studied. In all five species, the cambium was storied with variations in the length of fusiform cambial cells. Compared to other species S. foetida had the longest and S. urens the shortest fusiform cambial cells. Cambial rays in all the species were compound (tall) and heterocellular with sheath cells. Their height and width were maximal in S. foetida and in S. villosa respectively. In all the species the storied nature of fusiform cambial cells was maintained in derivative cells that developed into sieve tube elements; vessel elements and axial parenchyma of both phloem and xylem. However, fibres of phloem and xylem were nonstoried. The dimensions of elements in phloem and xylem varied among the species. The variation in the mean length of sieve tube elements and vessel members coincided with that of fusiform cambial cells.

scholarly journals Forage Production and Bromatological Composition of Forage Species Intercropped With Soybean

2019 ◽  
Vol 12 (1) ◽  
pp. 84
Author(s):  
Carlos Augusto Oliveira de Andrade ◽  
Emerson Borghi ◽  
Leandro Bortolon ◽  
Elisandra Solange Oliveira Bortolon ◽  
Francelino Peteno de Camargo ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Block Design ◽  
Production Capacity ◽  
Winter Period ◽  
Forage Production ◽  
Randomized Block Design ◽  
Forage Species ◽  
Urochloa Brizantha ◽  
Cattle Producer ◽  
Livestock System

Brazil is one the largest soybean and cattle producer worldwide and degrade pasture is one of the major problem in the Cerrado region. Integrated crop-livestock system is a key to increase grower income, to reduce crop yield loss by water deficit during growing season and to reclaim degraded pasture. However, forage production and its quality is important to evaluate under integrated crop-livestock system. The objective of this study was to evaluate forage production and the bromatological composition of different forage species in monoculture and in intercropping with soybean in an oversowing system. A completely randomized block design with four replications in a 5 &times; 2 + 1 factorial scheme, with five forage species (Urochloa brizantha cv. Marandu; U. ruziziensis; P. maximus cv. Momba&ccedil;a; P. infestans cv. Massai and P. americanum) and two cropping systems (monoculture and a consortium with soybeans) and a standard treatment (P. americanum in succession with soybeans). The forage productivity and the bromatological composition of the forages were evaluated. The species U. ruziziensis, U. brizantha, M. maximum and P. infestans presented higher forage production capacity, when cultivated in consortium with soybeans and in monoculture, in relation to P. americanum. The cultivation of the forages U. ruziziensis, U. brizantha, M. maximum and P. americanum in monoculture produced higher productivity than that in consortium with soybeans. The forages U. ruziziensis and U. brizantha intercropped with soybean presented a better nutritional value over the autumn-winter period.

Interactions between Source, Path and Sink in Determining Phloem Translocation Rate

1978 ◽  
Vol 5 (5) ◽  
pp. 665
Author(s):  
A Lang
Keyword(s):  
Hydrostatic Pressure ◽  
Sap Flow ◽  
Sieve Tube ◽  
Joint Control ◽  
Temperature Changes ◽  
Slightly Compressible ◽  
Steady Rate ◽  
Phloem Translocation ◽  
Sieve Tubes ◽  
The Individual

Treatments involving mild (5-10 Celsius degrees) temperature changes, spanning a range of mean temperatures, were imposed upon the source, path and sink regions of a translocating plant of Nymphoides geminata whilst the translocation rate was monitored. The temperature dependence (Q*10) of the rate of translocation was evaluated for each of these treatments. A new steady rate was achieved in only 3-5 min following a temperature change and was sustained for 2 h or more. Changes in rate were propagated down the sieve tubes at speeds more than ten times greater than those of sap flow, indicating that translocation involves the flow of a slightly compressible sap. The results suggest that translocation rate is normally under the joint control of source, path and sink regions of the plant. An attempt is made to assess their relative contributions to the overall control and this leads to the conclusion that, in this plant situation, the pathway predominates in controlling rate. It would seem that the individual rates of activity of source, path and sink regions are modulated by changes in the sieve tube sap concentration in their vicinity, these changes corresponding to, and being brought about rapidly by, changes in the hydrostatic pressure of this sap.

PARASITISM IN PHOLISMA (LENNOACEAE): II. ANATOMICAL ASPECTS

1967 ◽  
Vol 45 (7) ◽  
pp. 1155-1162 ◽  
Author(s):  
Job Kuijt
Keyword(s):  
Lateral Roots ◽  
Sieve Tube ◽  
Cambial Activity ◽  
Root Cap ◽  
Xylem Parenchyma ◽  
Vessel Elements ◽  
Xylem Elements ◽  
Host Tissues

The anatomy of roots and haustoria of Pholisma depressum is detailed. Lignified xylem consists of vessel elements only, and is associated with some xylem parenchyma. Sieve tube members exist in both the stem and the root. The pilot root is characterized by a restriction of cambial activity to the primary phloem regions, thus resulting in 3–5 bundle-like structures in older roots. From the protoxylem points between these bundles vascular flanges extend radially outward. The steles of lateral roots are extensions of these vascular flanges. A root cap is recognizable but very thin.The endophyte is a lobed organ with sinuous and irregular vascular strands lacking any phloem-like tissues. Strands, occasionally uniseriate, invade adjacent host tissues, usually in phloem-producing regions of the host cambium. These strands establish xylem-to-xylem contact, but are parallel to host xylem elements. They may subsequently become partially encapsuled by the latter. No radial sinkers exist.The nuclei of the endophyte show a more or less permanent type of heteropycnosis, the significance of which is unknown.A comparison of the parasitism of Lennoaceae and Orobanchaceae yields a number of significant differences in the structure and development of roots and haustoria.

Contractual Legitimacy in Organizations and Governments

1972 ◽  
Vol 13 (1) ◽  
pp. 18-33 ◽  
Author(s):  
Martin E. Spencer
Keyword(s):  
Social Structure ◽  
Social Contract ◽  
Rainy Season ◽  
Free Choice ◽  
Coercive Power ◽  
Mato Grosso ◽  
The Social ◽  
Primitive Forms ◽  
Nomadic Life ◽  
The Individual

In an essay on the Nambikuara of the Mato Grosso, Lévi-Strauss revives in an interesting fashion the problem of the Social Contract. Among the Nambikuara are found the most primitive forms of social and political structure. In the words of Lévi-Strauss: “No social structure is weaker and more fragile than the Nambikuara band” (I). The Nambikuara abandon their semi-permanent dwellings at the end of the rainy season in April or early May and divide into bands which are formed on the basis of free choice. The nucleus of the band is a leader who directs the movements and the hunting, fishing, and food-gathering activities of the group for the duration of its nomadic life during the dry season. The leader, however, disposes of no coercive power: he must derive his authority from the continual active consent of those subject to it. The price of leadership is the welfare of the group. If the band is badly managed and food is scarce the individual members of the group may leave to join other, more prosperous bands. Thus bands are always in the process of organizing and growing, or fragmenting and disappearing, with the vicissitudes of leadership. In return for his services the chief enjoys the privilege of having two or more wives, a prerogative shared only with the shamans. As Lévi-Strauss describes the situation of the leader, he appears to be a man forever hustling to provide his subjects with food and entertainment. He is in effect always running for office.

scholarly journals Does the lowering strategy before the stockpiling period modify the marandu palisade grass production and structure?

2021 ◽  
Vol 73 (6) ◽  
pp. 1403-1412
Author(s):  
M.E.R. Santos ◽  
G.O. Rocha ◽  
B.H.R. Carvalho ◽  
G.S. Borges ◽  
L.C. Adorno ◽  
...  
Keyword(s):  
Experimental Design ◽  
Forage Production ◽  
Grass Production ◽  
Urochloa Brizantha ◽  
In The Beginning

ABSTRACT The objective was to identify lowering strategies for Urochloa brizantha cv. Marandu in the beginning of the stockpiling period that increase forage production and improve the structure of stockpiled canopies. Three lowering strategies were evaluated: maintenance of marandu palisade grass with 15cm four months before the stockpiling period; maintenance of palisade grass with 30cm for four months, and lowering to 15cm before the stockpiling period; and maintaining of palisade grass at 45cm for four months, and lowering to 15cm before the stockpiling period. The experimental design was completely randomized, with four replications. At the end of stockpiling, the number of reproductive tillers and forage mass were higher in the canopy under 15/15cm than in the others; the percentage of live leaf was higher in the canopy under 45/15cm than under 15/15cm. Forage production during the stockpiling period was higher in the canopy under 15/15cm and lower in the under 45/15cm. Maintaining 15cm marandu palisadegrass for four months before the stockpiling period increases forage production during this period. The lowering of the marandu palisadegrass from 45 to 15cm at the beginning of the stockpiling period improves the structure of the stockpiled canopy.

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