Temperature and Leaf Growth in Lolium perenne. I. The Thermal Microclimate: Its Measurement and Relation to Crop Growth

Ma, Aiqun; W, Wang; Wang, H; Yang, Yuqin; Ke, Wei; Fu, Yicheng

doi:10.2307/2401720

Cited by 75 publications

(56 citation statements)

References 15 publications

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“…Bar above the columns correspond to mean standard error. average temperatures (Figures 1 and 2), resulting in restritive environmental conditions to plant growth and development, which, therefore, reduced the leaf elongation rate (Peacock, 1975). The combination of these factors contributed to the low final leaf blade length observed during this period.…”

Section: Resultsmentioning

confidence: 98%

Morphogenetic and structural characteristics of andropogon grass submitted to different cutting heights

Sousa¹,

Júnior²,

Silva

et al. 2010

R. Bras. Zootec.

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-This work was performed aiming to evaluate the morphogenetic and structural characteristics of Andropogon gayanus cv. Planaltina species submitted to three cutting heights (20, 27 and 34 cm). The three cutting heights were allocated in experimental units (12 m 2 ) in a complete randomized block design with three replications. The cuts were done when the light interception by the sward reached 95%. At this moment, the sward height revealed itself constant with values close to 50 cm. The lowest cutting height (20 cm) influenced negatively the final leaf blade length, the number of live leaves, the leaf lifespan, the stem elongation rate and the tiller population density, and it influenced positively the phyllochron and the leaf senescence rate. Probably, cuts at 20 cm height caused a high decapitation and death of the tillers. The worst growth conditions in addition to the blossom of this specie occurred during fall resulted in higher stem elongation rates and number of live leaves, and lower phyllochron, final leaf blade length, and leaf lifespan. The sward height can be used as a practical and efficient criterion in the management of andropogon grass. Under intermittent management conditions, the regrowth of andropogon grass must be interrupted when the sward reaches 50 cm height, and the defoliation must be interrupted when the stubble height is close to 27 cm.Key Words: Andropogon gayanus, ecophysiology, light interception, morphogenesis, sward height Características morfogênicas e estruturais do capim-andropógon submetido a diferentes alturas de corte RESUMO -Este trabalho foi realizado com o objetivo de avaliar as características morfogênicas e estruturais da espécieAndropogon gayanus cv. Planaltina, submetida a três alturas de corte (20, 27 e 34 cm). As três alturas de corte foram alocadas às unidades experimentais (12 m 2 ) em delineamento de blocos completos casualizados com três repetições. Os cortes foram realizados quando a interceptação luminosa pelo dossel atingiu 95%. A altura do dossel nesse momento mostrou-se constante, com valores próximos a 50 cm. A menor altura de corte (20 cm) influenciou negativamente o comprimento final da lâmina foliar, o número de folhas vivas, a duração de vida da folha, a taxa de alongamento de colmo e a densidade populacional de perfilhos, e positivamente o filocrono e a taxa de senescência de folhas. Provavelmente, cortes a 20 cm de altura causaram elevada decapitação e morte de perfilhos. As piores condições de crescimento junto do florescimento ocorrido durante o outono resultaram em maiores taxas de alongamento de colmos e número de folhas vivas e em menor filocrono, comprimento final da lâmina foliar e duração de vida da folha. A altura do dossel pode ser utilizada como critério prático e eficiente de manejo do capim-andropógon. Em condições de manejo intermitente, a rebrotação deve ser interrompida quando o dossel atingir 50 cm de altura, e a desfolhação, quando a altura de resíduo ficar próxima de 27 cm.

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Section: Resultsmentioning

confidence: 98%

Morphogenetic and structural characteristics of andropogon grass submitted to different cutting heights

Sousa¹,

Júnior²,

Silva

et al. 2010

R. Bras. Zootec.

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“…A temperatura influencia a dinâmica de acúmulo de massa à medida que a resposta da taxa de alongamento foliar à variação em temperatura é imediata (Peacock, 1975;Lemaire & Agnusdei, 2000), de tal forma que a produção de tecidos segue exatamente as variações térmicas sazonais. Além da taxa de alongamento foliar, a taxa de aparecimento das folhas também é afetada pelo efeito sinérgico da temperatura e umidade, pois a taxa de aparecimento das folhas é influenciada por fatores do meio.…”

Section: Resultsunclassified

“…Após a obtenção dos escores fatoriais, estes foram utilizados como base para realização de análise multivariada de agrupamento por otimização, segundo o método de Tocher (Cruz & Regazzi, 1997). No método de otimização proposto por Tocher, é adotado o critério de manter a distância média intragrupos sempre inferior a qualquer distância intergrupos (Rao, 1952). Foi adotada a distância euclidiana média como medida básica de dissimilaridade.…”

Section: Methodsunclassified

Grupos funcionais de gramíneas forrageiras tropicais

et al. 2012

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RESUMO -Foram avaliadas as características morfogênicas e estruturais de gramíneas forrageiras com o objetivo de agrupá-las, de acordo com seu padrão de desenvolvimento, em seus respectivos grupos funcionais. As gramíneas foram plantadas em parcelas de 1,0 m 2 com 24 plantas, em delineamento de blocos completos casualizados com três repetições. Os dados foram submetidos à análise de fatores, reduzindo as variáveis em quatro fatores: desenvolvimento de massa, mortalidade de perfilhos, estádio de desenvolvimento e longevidade foliar. Os dados foram submetidos à análise de agrupamento por otimização de Tocher adotando-se a distância euclidiana média como medida básica de dissimilaridade. As gramíneas foram agrupadas da seguinte forma: Verão -grupo I (Xaraés, Massai, Mombaça e Marandu); grupo II (Gordura e Aruana); e grupo III (Jaraguá). Outonogrupo I (Mombaça, Massai, Xaraés, Marandu e Gordura); grupo II -(Jaraguá); e grupo III (Aruana). Possivelmente a maior participação do fator mortalidade de perfilhos na formação dos grupos no período de outono influenciou na reorganização dos grupos. Os padrões de desenvolvimento de massa dos diferentes grupos de gramíneas diferiram entre si quanto à forma de utilização dos recursos disponíveis. Houve mudança nos escores de todos os fatores com a mudança do período do verão para o outono. O agrupamento funcional comprova que gramíneas de gêneros e/ou espécies diferentes podem ser enquadradas em um mesmo grupo.Palavras-chave: análise multivariada, avaliação de gramíneas, características estruturais, morfogênese Functional clusters of tropical forage grassesABSTRACT -Morphogenetic and structural characteristics of forage grasses were evaluated in order to group them according to their pattern of development in their respective functional groups. Grasses were planted in plots of 1.0 m 2 with 24 plants in a completely randomized block design with three replications. Data were submitted to factor analysis, reducing the variables to four factors: mass development, tiller mortality, developmental stage and leaf longevity. The data were submitted to cluster analysis by Tocher's optimization by adopting the mean Euclidean distance as a basic measure of dissimilarity. Grasses were grouped as follows: Summer -the group I (Xaraés, Massai, Mombaca and Marandu); group II (Molassa and Aruana); and group III (Jaraguagrass). Fall -group I (Mombaca, Massai, Xaraés, Marandu and Molassa); group II -(Jaraguagrass); and group III (Aruana). Possibly, the greater role of the tiller mortality factor in the formation of groups in the fall influenced the reorganization of the groups. The patterns of mass development of the different groups of grasses differ from each other as for the means of utilizing the resources available. There was a change in the scores of all factors with the change of the period from summer to Fall. The functional clustering of grasses demonstrates that gender and/or different species can be placed in the same group.

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“…The use of photosynthesized nutrients by the foliar meristems is regulated by the temperature (Ben Haj Salah & Tardieu, 1995). and when variations positive of temperature are sensed by the apical meristem, there is increase in the leaf elongation rate (Peacock, 1975). Duru & Ducrocq (2000) observed significant increases in leaf appearance rate and in the number of leaves with changes in the temperature, which indicates that this environmental factor is one of the most important in leaf appearance rate control (Bauer et al, 1984).…”

Section: Discussionmentioning

confidence: 94%

“…Results from chemical analysis of soil (Raij et al, 1986) for the 0-20 cm layer were: pH in H 2 O = 5.05; P = 2.03 (Mehlich-1) and K = 151 mg/dm 3 ; Ca = 1.95; Mg = 1.25; Al = 0.03; H+Al = 3.81 and cation exchange capacity = 35.9 mmol c /dm 3 ; base saturation = 48.5%.…”

Section: Methodsmentioning

confidence: 99%

Morphogenesis in guinea grass pastures under rotational grazing strategies

Montagner¹,

Júnior²,

Sousa³

et al. 2012

R. Bras. Zootec.

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-This study was conducted in order to evaluate the morphogenetic and structural characteristics of guinea grass cv. Mombasa under three post-grazing heights (intense -30 cm, lenient -50 cm and variable -50 in springsummer and 30 cm in autumn-winter) when sward light interception reached 95% during regrowth. Post-grazing heights were allocated to experimental units (0.25 ha) in a completely randomized block design with three replications. Postgrazing heights affected only leaf elongation rate and the number of live leaves. Pastures managed with variable postgrazing height showed higher leaf elongation rate in the summer of 2007. This management strategy also resulted in a higher number of live leaves. During the spring of 2006, plants showed lower leaf elongation rate, leaf appearance rate and number of live leaves, and greater phyllochron and leaf lifespan. In contrast, during the summer of 2007, the leaf appearance rate, leaf elongation rate, number of live leaves, and final leaf length were greater while phyllochron, stem elongation rate, and leaf senescence rate were lower. The management of the guinea grass cv. Mombasa with intense or variable post-grazing height throughout the year seems to represent an interesting management target, in terms of leaf appearance rate and number of live leaves.

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Temperature and Leaf Growth in Lolium perenne. I. The Thermal Microclimate: Its Measurement and Relation to Crop Growth

Cited by 75 publications

References 15 publications

Morphogenetic and structural characteristics of andropogon grass submitted to different cutting heights

Morphogenetic and structural characteristics of andropogon grass submitted to different cutting heights

Grupos funcionais de gramíneas forrageiras tropicais

Morphogenesis in guinea grass pastures under rotational grazing strategies

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