scholarly journals Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

2010 ◽  
Vol 22 (4) ◽  
pp. 245-254 ◽  
Author(s):  
Anandra S. Silva ◽  
Jurandi G. Oliveira ◽  
Maura da Cunha ◽  
Angela P. Vitória
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Rainy Season ◽  
Photosynthetic Pigment ◽  
Photosynthetic Performance ◽  
Dry Season ◽  
Limiting Factor ◽  
Native Forest ◽  
The Sun ◽  
Adaxial Epidermis

The photosynthetic dynamics of the tropical pioneer species, Byrsonima sericea DC., were studied during the regeneration process of a native forest by evaluating ecophysiological (gas exchange, chlorophyll a fluorescence and photosynthetic pigment contents) and anatomical parameters of plants in sunny and shady environments. Ecophysiological evaluations were carried out monthly for one year, encompassing both a dry and a rainy season. Byrsonima sericea DC. presents anatomical plasticity that enables it to establish in environments with contrasting light regimes. In sunny conditions, it produced a thicker leaf (about 420 mm) and flat adaxial epidermis, whilst in the shade, leaves had a thinner convex adaxial epidermis (about 395 mm). No differences were found in the compositions of the pigments in the different environments, however, during the dry season, the plants presented a significantly higher concentration of photosynthetic pigments. In the sun, plants showed decreases in Fv/F0 ratio (in the rainy season) and NPQ (in the dry season), but no difference was observed between plants that were in the sun or in the shade. A significantly higher net photosynthetic rate was found only in the rainy season in the plants in the sun, compared to shaded plants (9.9±0.8 and 7.4±0.3 µmol m-2s-1, respectively). Significant increase in transpiration was observed in plants in the shade during the dry season, but no alterations were observed in the water use efficiency. Ecophysiological data suggest that mainly plants overexposed to the sun underwent water limitations during the dry season and that, in the rainy season, these plants increased their net photosynthetic rate, possibly due to the greater drainage force resulting from increased growth during this period. Data suggest that anatomic alterations, namely the convex adaxial epidermis, could aid in the supply of light to shaded plants during both seasons, precluding changes in the pigments, such as the increase in chlorophyll b usually observed in shaded plants, but not detected in the present study. Another consequence of the greater quantity of light captured by these shade plants is that during the dry season their net photosynthetic rate was not different from that of plants in a sunny environment. However, when water was not a limiting factor, a better photosynthetic performance was observed in this pioneer specie in open spaces.

Mosquitos bred from Dry Material taken from Holes in Trees

1926 ◽  
Vol 17 (2) ◽  
pp. 183-187 ◽  
Author(s):  
Lawrence H. Dunn
Keyword(s):  
Yellow Fever ◽  
Rainy Season ◽  
Dry Season ◽  
Western Hemisphere ◽  
The Sun ◽  
Living Tree ◽  
Tree Holes ◽  
Control Work ◽  
Short Time ◽  
Selection Of

An investigation of the breeding habits of the yellow fever mosquito, Aëdes aegypti, Linn., in West Africa was begun in December 1925. This was undertaken for the purpose of ascertaining if the selection of breeding-places of this mosquito in Africa differs from that in the Western Hemisphere, and, if so, to learn if this difference is sufficient to be of material importance in yellow fever control work.Since it was believed that breeding in tree-holes constituted a problem worthy of investigation, it was decided to make a survey of the rot-holes and fork-hollows in trees in the vicinity of Lagos, in the Southern Province of Nigeria. This survey was begun on 8th December 1925, shortly after the rainy season had passed and the dry season had set in. However, after inspecting a number of trees, the fact became evident that this was not a propitious time of the year for finding larvae in such places, since practically all of the holes were without water, and their contents, consisting of leaves and débris, were dry.This early drying of the material in the holes drew my attention to the probability of mosquito eggs remaining in the holes, surviving the drought of the dry season and producing larvae with the beginning of the rains. In furtherance of this question, an examination of the dry holes was then began, and material collected from all those that were suitable. The term “ suitable ” in this sense signifies that the hole was in a living tree—of a formation to contain water, for a short time at least—that the aperture was of sufficient size to allow the débris to be removed and the inside of the hole scraped, and that the contents were dry. The distance of the trees from habitations, their location in open areas or thick bush, the height of the holes from the ground, the exposure of the holes to the sun, or the amount of débris contained caused no discrimination to be made.

scholarly journals Soil macrofauna as a bioindicator of soil quality in successional agroforestry systems

2021 ◽  
Vol 10 (10) ◽  
pp. e580101019144
Author(s):  
Rafaela Martins da Silva ◽  
Rakiely Martins da Silva ◽  
Sandra Santana de Lima ◽  
Jianne Rafaela Mazzini de Souza ◽  
Jheny Kesley Mazzini de Souza ◽  
...  
Keyword(s):  
Soil Quality ◽  
Rainy Season ◽  
Agroforestry System ◽  
Agroforestry Systems ◽  
Dry Season ◽  
Native Forest ◽  
Secondary Forests ◽  
Euterpe Oleracea ◽  
Soil Macrofauna ◽  
Time Of Collection

The objective of this study was to evaluate soil macrofauna as a bioindicator of soil quality in successional agroforestry systems and secondary forests. The study was conducted in the southern lower region of Bahia in Brazil, in two areas: a successional agroforestry system (AFS18) and native forest (NF).  AFS18 consists of two species: mahogany (Khaya ivorensis and Khaya grandifoliola), açaí (Euterpe oleracea), cacao (Theobroma cacau) and banana (Musa spp.).  Sampling was carried out in the dry (June) and rainy (October) seasons of 2019, and eight soil monoliths were collected in both areas.  A total of 889 individuals from the soil macrofauna were sampled. The highest frequency (RF) of taxons occurred in NF in the rainy season, and the groups that stood out were: Oligochaeta with 42% FR in ASF18, Formicide with 33.9% in NF and Isoptera with 58% in AFS18. The macrofauna structure of the soil varied according to the time of collection. The density of macrofauna individuals differed between areas only in the dry season. The highest number of ind.m² was observed in the area NF (378) when compared to ASF18 (196). TOC, Mg2+, Al3+ and CTC were related to AF on both occasions of collection and AFS18 in the rainy season, K+, P and pH were associated with AFS18 in the dry season. The diversity, equitability and richness of the soil macrofauna was greater in AF area. HFA18 in the rainy season was similar to NF, favoring colonization of the area by soil macrofauna organisms.

Litterfall production and fluvial export in headwater catchments of the southern Amazon

2007 ◽  
Vol 23 (3) ◽  
pp. 329-335 ◽  
Author(s):  
Evandro Carlos Selva ◽  
Eduardo Guimarães Couto ◽  
Mark S. Johnson ◽  
Johannes Lehmann
Keyword(s):  
Rainy Season ◽  
Riparian Zone ◽  
Stream Water ◽  
Dry Season ◽  
Native Forest ◽  
Lateral Movement ◽  
Mato Grosso ◽  
Litterfall Production ◽  
Forested Landscapes ◽  
Southern Amazonia

Resolving the carbon (C) balance in the Amazonian forest depends on an improved quantification of production and losses of particulate C from forested landscapes via stream export. The main goal of this work was to quantify litterfall, the lateral movement of litter, and the export of coarse organic particulate matter (>2 mm) in four small watersheds (1–2 ha) under native forest in southern Amazonia near Juruena, Mato Grosso, Brazil (10°25′S, 58°46′W). Mean litterfall production was 11.8 Mg ha−1 y−1 (5.7 Mg C ha−1 y−1). Litterfall showed strong seasonality, with the highest deposition in the driest months of the year. About two times more C per month was deposited on the forest floor during the 6-mo dry season (0.65 Mg C ha−1 mo−1) compared with the rainy season (0.3 Mg C ha−1 mo−1). The measured C concentration of the litterfall samples was significantly greater in the dry season than in the rainy season (49% vs. 46%). The lateral movement of litter increased from the plateau (upper landscape position) towards the riparian zone. However, the trend in C concentration of laterally transported litter samples was the opposite, being highest on the plateau (44%) and lowest in the riparian zone (42%). Stream-water exports of particulate C were positively correlated with streamflow, increasing in the rainiest months. The export of particulate C in streamflow was found to be very small (less than 1%) in relation to the amount of litterfall produced.

scholarly journals BIODIVERSIDADE DE BACTÉRIAS ANTAGÔNICAS A FUNGOS ASSOCIADOS À SINDROME DA MORTE DO CAPIM-MARANDU (Brachiaria brizantha)

Nativa ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 454-459
Author(s):  
Maira Laís Both Bourscheidt ◽  
Kellen Banhos do Carmo ◽  
Bruno Carneiro Pedreira ◽  
Gilcele de Campos Martin Berber ◽  
Anderson Ferreira
Keyword(s):  
Biological Control ◽  
Rainy Season ◽  
Production Systems ◽  
Dry Season ◽  
Native Forest ◽  
Bacterial Isolates ◽  
Fusarium Spp ◽  
Brachiaria Brizantha

A síndrome da morte do capim-marandu (Brachiaria brizantha) é um dos principais problemas na degradação das pastagens no bioma Amazônia. A morte das forrageiras ocorre durante a época chuvosa por suscetibilidade a fitopatógenos. Assim, objetivou-se estudar sistemas de produção e selecionar bactérias antagônicas a Fusarium spp., um dos agentes fitopatogênicos. Os isolados bacterianos foram obtidos de 10 sistemas de produção, mata nativa e pousio, na chuva e na seca. Realizou-se a caracterização molecular de isolados por sequenciamento. Dois isolados de Fusarium foram testados. Para o patógeno 1, na época da chuva, 7,5% dos isolados apresentaram antagonismo enquanto na seca foi 15%. Para o patógeno 2, nem todos os isolados positivos para o patógeno 1 foram eficientes no controle, demonstrando a ocorrência de interações entre isolados bacterianos e Fusarium spp. Na chuva, para o patógeno 1, a mata apresentou maior número de isolados positivos (20%). Na seca, os tratamentos mata, 1-Floresta e 8-integração lavoura floresta para o patógeno 1, foram os que apresentaram maior número de positivos (25%). Na identificação molecular, 8 foram os gêneros bacterianos encontrados: Burkholderia, Bacillus, Brevibacillus, Streptomyces, Pseudomonas, Escherichia, Paenibacillus e Pandoraea, em que a maioria é descrita como capaz de controlar Fusarium spp. in vitro. Palavras-chave: Burkholderia; controle biológico; integração lavoura-pecuária-floresta.   Biodiversity of bacteria antagonic to fungi associated with syndrome's death palisadegrass (Brachiaria brizantha)   ABSTRACT: The death syndrome of marandu grass (Brachiaria brizantha) is one of the main problems in the degradation of pastures in the Amazon biome. Plant death occurs during the rainy season due to susceptibility to phytopathogens. Thus, the objective was to study production systems and select bacteria antagonistic to Fusarium spp., one of the phytopathogenic agents. Bacterial isolates were obtained from 10 production systems, native forest and fallow, in rain and drought season. Molecular characterization of isolates was carried out by sequencing. Two Fusarium isolates were assessed. For pathogen 1, in the rainy season, 7.5% of the isolates showed antagonism, while in the dry season it was 15%. For pathogen 2, not all isolates positive for pathogen 1 were efficient in the control, showing correlations between bacterial isolates and Fusarium spp. In the rain, for pathogen 1, the forest showed the highest number of positive isolates (20%). In the dry season, the treatments forest, 1-Forest and 8-plant-forest integration for pathogen 1, were ones with the highest number of positives (25%). In the molecular identification, 8 bacterial genera were found: Burkholderia, Bacillus, Brevibacillus, Streptomyces, Pseudomonas, Escherichia, Paenibacillus and Pandoraea, most of which are described as able to controlling Fusarium spp. in vitro. Keywords: Burkholderia; biological control; integrated crop-livestock-forest.

scholarly journals Experimental Study on The Effect of Arches Setting on Semi-Flexible Monocrystalline Solar Panels

2020 ◽  
pp. 111-118
Author(s):  
Iwan Arissetyadhi ◽  
Tresna Dewi ◽  
RD Kusumanto
Keyword(s):  
Experimental Study ◽  
Renewable Energy ◽  
Rainy Season ◽  
Solar Power ◽  
Dry Season ◽  
Solar Panel ◽  
The Sun ◽  
Solar Panels ◽  
Energy Potential ◽  
Convex Setting

Indonesia has a high potential for renewable energy, especially solar power, due to its location in the equator and blessed with an abundance of sunlight. However, the energy potential from the sun is not maximally utilized. One of the efforts to increase the generated electricity and efficiency is by applied the panels in arches setting. This setting is made possible by the availability of the semi-flexible monocrystalline solar panel. This paper investigates the increment of harvested power and efficiency by arranging the solar panel in concave, convex, and plane settings. The data were taken in August 2019, where Palembang experiences the dry season and January 2020 during the rainy season. The highest power produced (20.27 Watt) and efficiency (13.14%) were achieved in a concave setting during the dry season. The convex setting produced more power and efficiency (13.26 Watt and 9.30%) compared to the plane setting (10.24 Watt and 9.71%). These results show that arches setting are more efficient to harvest solar power and give more extensive applications such as to power a dynamics mobile robot applied in agriculture.

scholarly journals Differences in Characteristics of Photosynthesis and Nitrogen Utilization in Leaves of the Black Locust (Robinia pseudoacacia L.) According to Leaf Position

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 348
Author(s):  
Dongsu Choi ◽  
Woongsoon Jang ◽  
Hiroto Toda ◽  
Masato Yoshikawa
Keyword(s):  
Electron Transport ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Environmental Changes ◽  
Robinia Pseudoacacia ◽  
The Sun ◽  
Bisphosphate Carboxylase ◽  
Robinia Pseudoacacia L ◽  
Shade Leaves ◽  
Sun Leaves

Robinia pseudoacacia L. has been widely planted worldwide for a variety of purposes, but it is a nonindigenous species currently invading the central part of Japanese river terraces. To understand and control this invasion, we investigated how this species invests nitrogen resources in different functions depending on the leaf location, and how these resources are used in physiological reactions such as photosynthesis. The Tama river terrace was examined in Tokyo, Japan. The leaf nitrogen (N) concentration, chlorophyll (Chl) concentration, Chl a/b ratio, leaf mass per unit area (LMA) and ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCo) concentration were all significantly lower in shade leaves than in leaves exposed to the sun. Conversely, the net photosynthetic rate in saturated light conditions (Pmax), the net photosynthetic rate under enhanced CO2 concentration and light saturation (Amax), the maximum carboxylation rate of RuBisCo (Vcmax) and the maximum rate of electron transport driving RUBP regeneration (Jmax) were all significantly lower in shade leaves than in leaves exposed to the sun. We also found that RuBisCo/N and Chl/N were significantly less in shade leaves, and values of Jmax/N, Vcmax/N less in shade leaves than in sun leaves, but not significantly. Allocation of nitrogen in leaves to photosynthetic proteins, RuBisCo (NR) was broadly less in shade leaves, and NL (light-harvesting complex: LHC, photosystem I and II: PSI and PSII) and NE (electron transport) were also lower. The N remaining was much greater in shade leaves than in sun leaves. We suggest that N remobilization from RuBisCo is more efficient than remobilization from proteins of NE, and from NL. This study shows that R. pseudoacacia has an enhanced ability to adapt to environmental changes via characteristic changes in N allocation trade-offs and physiological traits in its sun and shade leaves.

scholarly journals Effect of Enhanced UV-B Radiation on Fruit Maturity and Quality, and Leaf Photosynthesis in ' Guifei ' Mango

2021 ◽  
Author(s):  
Xiaokai Lin ◽  
Haizhi Liao ◽  
Jingjia Du ◽  
Junjie Peng ◽  
Kaibing Zhou
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Fruit Quality ◽  
Radiation Treatment ◽  
Mangifera Indica ◽  
Photosynthetic Pigment ◽  
Photochemical Quenching ◽  
Hill Reaction ◽  
Early Maturity ◽  
Fruit Maturity

(1) Background: Investigating the characteristics of photosynthetic physiological changes of leaves in Mangifera indica L. cv. 'GuIfei' under enhanced UV-B radiation, natural light exposed trees were regarded as control, and 96 kJ·m-2·d-1enhanced UV-B radiation was artificially simulated in the field; (2) Methods: The changes of fruit maturity and fruit quality, leaf net photosynthetic rate (Pn), photosynthetic pigments contents, photochemical reaction, activities of photosynthetic enzymes and their genes expressions were determined; (3) Results: Compared with CK, the percentage of mature fruits of the treatment was significantly increased, and fruit quality was better. The net photosynthetic rate (Pn), the contents of photosynthetic pigment, Hill reaction activity and photochemical quenching coefficient (qP) of the treatment leaves showed a significantly higher trend than CK. The activities of Rubisco and RCA, and the expression of Rubisco genes rbcL and rbcS were significantly increased; (4) Conclusions: 96 kJ·m-2·d-1 enhanced UV-B radiation treatment improved Rubisco activity through increasing the expression of Rubisco genes rbcL and rbcS, thereby enhancing the CO2-fixing capacity and dark reaction capacity of leaves. Based on this, it raised the net photosynthetic rate of leaves, which promoted the early maturity of 'Guifei' mango by the fast accumulating photosynthetic products.

scholarly journals Chlorophyll content, photosynthetic efficiency and genetic markers in two sour cherry (Prunus cerasus L.) genotypes under drought stress

2013 ◽  
Vol 72 (2) ◽  
pp. 221-235 ◽  
Author(s):  
Marija Viljevac ◽  
Krunoslav Dugalić ◽  
Ines Mihaljević ◽  
Domagoj Šimić ◽  
Rezica Sudar ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Water Status ◽  
Photosynthetic Pigment ◽  
Photosynthetic Apparatus ◽  
Sour Cherry ◽  
Fruit Production ◽  
Photosynthetic Performance ◽  
Limiting Factor ◽  
Relative Water ◽  
Photosynthetic Pigment Content

Abstract - Drought is a limiting factor in fruit production today. Identification of sour cherry genotypes tolerant to drought will enable the sustainability of fruit production. The aim of our study was to select sour cherry genotypes according to their genetic background as well as drought tolerance and investigate possible mechanisms of drought tolerance through the changes in photosynthetic apparatus (i.e. photosynthetic pigment content) and photosynthesis process assessed through the chlorophyll fluorescence transient. All of them together with molecular markers (SSRs and AFLPs), relative water content (RWC) as indicator of plant water status distinguish two genotypes (Kelleris 16 and OS), which are the opposite in regards to drought tolerance. Down-regulation of photosynthesis in drought-treated Kelleris 16 plants was seen as changes in antenna complexes of PSII (decreased total chlorophylls content (a+b) and chlorophylls ratio (a/b)). Despite unchanged maximum quantum yield of PSII in drought-treated leaves of genotype OS, overall photosynthetic performance expressed as PIABS was down-regulated in both investigated genotypes. However, decrement of PIABS was much pronounced in genotype Kelleris 16, mainly because of changes in a certain fraction of RCs, which become dissipative centres, seen as increase in ABS/RC and DI0/RC, in order to avoid photooxidative damage of photosynthetic apparatus. Also, electron transport, seen as decrease in ET0/(TR0-ET0) and ET0/RC, was impaired which lead to impaired CO2 fixation and photosynthesis. The described changes in the functioning of photosynthetic apparatus in drought-treated plants of Kelleris 16 constitute the main distinction between the two investigated genotypes regarding drought adaptation mechanisms.

STUDI BIONOMIK VEKTOR MALARIA DI KECAMATAN KALIBAWANG, KULONPROGO

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Sardjito Eko Windarso dkk
Keyword(s):  
Land Use ◽  
Malaria Vector ◽  
Rainy Season ◽  
Dry Season ◽  
Physical Factors ◽  
Mosquito Vector ◽  
Anopheles Species ◽  
Commercial Farming ◽  
Study Results ◽  
Dry And Rainy Seasons

The increasing of malaria cases in recent years at Kecamatan Kalibawang has been suspected correspond with the conversion of farming land-use which initiated in 1993. Four years after the natural vegetation in this area were changed become cocoa and coffee commercial farming estates, the number of malaria cases in 1997 rose more than six times, and in 2000 it reached 6085. This study were aimed to observe whether there were any differences in density and diversity of Anopheles as malaria vector between the cocoa and mix farming during dry and rainy seasons. The results of the study are useful for considering the appropriate methods, times and places for mosquito vector controlling. The study activities comprised of collecting Anopheles as well as identifying the species to determine the density and diversity of the malaria vector. Both activities were held four weeks in dry season and four weeks in rainy season. The mea-surement of physical factors such as temperature, humidity and rainfall were also conducted to support the study results. Four dusuns which meet the criteria and had the highest malaria cases were selected as study location. Descriptively, the results shows that the number of collected Anopheles in cocoa farming were higher compared with those in mix horticultural farming; and the number of Anopheles species identifi ed in cocoa farming were also more varied than those in the mix horticultural farming.Key words: bionomik vektor malaria, anopheles,

Sign in / Sign up

Export Citation Format

Share Document