Plant Dry Matter Weight Research Articles

Características fisiológicas de porta-enxertos de videira em solução salina

A tolerância de cinco porta-enxertos de videira ('IAC 766 Campinas', 'IAC 313 Tropical', 'IAC 572 Jales', '420-A' e 'Ripária do Traviú') à salinidade foi avaliada em um ensaio, em casa de vegetação, em solução nutritiva, com cinco níveis de NaCl (0, 5, 10, 15 e 20 mmol L-1). Foram determinados a taxa fotossintética, a condutância estomática, a taxa transpiratória, a altura de plantas e o peso da matéria seca. A altura de planta e o peso da matéria seca foram afetados pelo incremento da salinidade. As cultivares mais tolerantes ('IAC 572', 'IAC 766' e 'Ripária do Traviú') apresentaram, mesmo nas maiores doses de NaCl, fotossíntese líquida de 0,75 mimol m-2 s-1, acompanhada pela manutenção da abertura estomática e da taxa transpiratória.

Growth and Competitiveness of Common Lambsquarters (Chenopodium album) after Foliar Application ofAscochyta caulinaas a Mycoherbicide

Control of common lambsquarters by the use ofAscochyta caldinaas a postemergence mycoherbicide was studied in corn and sugar beet, in 1992 or 1993. The weed was planted at determined positions in the crops. Plots were treated with suspensions ofA. caulinaspores, and wetness duration's were varied to create different levels of disease development. Application ofA. caulinaresulted in necrosis development on, and mortality of common lambsquarters. Average severities of leaf necrosis 1 wk after treatment ranged from 0.01 to 0.75. Average proportions of dead plants 3 wk after treatment ranged from 0.00 to 0.65. Necrosis development and mortality were affected by wetness duration in two experiments. Sublethally diseased plants showed reduced growth. Maximum dry matter was affected by crop and by necrosis development. Numbers of fruits per plant showed a positive, almost linear relationship with plant dry matter weight. Seed weight was less affected by necrosis than number of fruits per plant. Competitiveness of common lambsquarters was reduced after infection byA. caulina.Crop dry matter weight showed a positive relationship with the level of common lambsquarters control. In corn, yield reduction by competition was prevented by application of A.caulina, but not in sugar beet.

Phosphorus availability and phosphate fraction relationships in volcanic ash soils

The effects of liming and phosphorus (P) application on sorghum seedlings (Sorghum vulgare L.) grown in three volcanic ash soils (Camembaro, umbric; Bosque, vitric; and San Gregorio, mollic) were studied in a greenhouse, and relationships between soil P fractions, plant dry matter, and P uptake were examined. Results showed that P application improved plant growth (dry matter and P uptake) significantly (p < 0.001); effect of liming on these crop growth parameters, however, was not consistent. Correlation coefficients between the most abundant inorganic P (P:) forms, resin‐P and NaHCO3‐P, and plant dry matter weight and P uptake were highly significant: r = 0.958 for resin‐P versus dry matter; r = 0.960 for resin‐P versus P uptake; r = 0.837 for NaHCO3‐P versus dry matter; and r = 0.848 for NaHCO3‐P versus P uptake. Plant dry matter and P uptake were partially dependent on organic P (Po) by contributing to total soil P and suggesting that Po may play an important role in plant P availability in these andosols.

Wheel Traffic Effects on Corn Growth

Corn growth as affected by soil compaction due to wheel traffic before secondary tillage was studied. Compaction treatments included none, between rows, on rows, and on entire plot area. Corn yields with wheel traffic on entire plot area averaged 9.8 Mg/ha which was significantly lower than yields with the other treatments which averaged 12.5 Mg/ha with no traffic and 12.6 Mg/ha with traffic between rows and with traffic on rows. Corn plant height and dry matter weight throughout the growing season, and root mass assessed soon after tasseling, were also lower with wheel traffic on entire plot area compared to the other treatments.

Correlações entre parâmetros da análise de crescimento de cultivares de tomateiro (Lycopersicon esculentum Mill.)

No presente trabalho, estudaram-se as possíveis correlações entre os parâmetros da análise quantitativa de crescimento vegetal , através dos dados de experimento conduzido com as culti vares de tomateiro, Kada, Angela, Floradel e Tropic, em sistema de cultivo para as condições do trópico-úmido, em Manaus, Amazonas , Brasil. A partir da semeadura, a cada 14 dias, durante todo o ciclo do tomateiro, foram colhidas plantas e determinadas a altura, área foliar, peso da matéria seca da planta e peso da matéria fresca e seca dos frutos. Executou-se, dessa forma, a análise de crescimento vegetal dos cultivares e a correlação entre os parâmetros avaliados na planta: altura,, produção, peso da matéria seca (PMS) , índice de área foliar (IAF) , taxa de produção de matéria seca (TPMS), taxa de produção de matéria seca vegetativa (TPMSV), taxa de produção de matéria seca dos frutos (TPMSF) taxa de crescimento relativo (TCR) e taxa de assimilação líquida (TAL). No estudo das correlações entre os parâmetros, a altura foi o que apresentou maior quantidade de altas correlações, sendo assim, um bom índice para se estimar o desenvolvimento da planta. Existem correlações positivas: a) da altura com o IAF, com a produção, com o PMS e com a TPMS, ou seja, esses parâmetros estão diretamente correlacionados com a altura; b) do PMS com a produção e com o IAF. A TAL é mais afetada pela TCR, já que apresentou todos os coeficientes de correlação com valores baixos, e dentre eles, o mais elevado foi com a TCR. A TCR só teve altas correlações com a altura e o IAF, sendo essas correlações negativas, ou seja, à medida que a planta cresce, diminui a TCR. Os cultivares mais produtivos apresentaram altas correlações positivas entre TMSF e TPMS, mostrando ser a produtividade econômica diretamente afetada pela produtividade biológica nesses cultivares.

Genetic specificity in relation to plant mineral nutrition

Abstract The present paper deals with methodology, criteria, and directions of the investigation in genetic specificity of plant mineral nutrition. The genetic specificity is found in a great number of plant species such as maize, wheat, soyabean, apple, sugarbeet, grape, etc. The content and concentration of elements in genotypes of the same plant species vary greatly. These variations are affected by growth conditions of plants as well as their developmental stages. Therefore, they may be established in the same growth conditions and at the same developmental stages only. Also, genetic specificity in plant mineral nutrition may be affected by certain physiological and biochemical processes. Genetic specificity in plant mineral nutrition is manifested not only through the element content of certain plant organs but in the morphological and physiological features and in plant dry matter weight.

Heterosis During the Early Phases of Growth in Intraspecific and Interspecific Crosses of Cotton1

The performance of interspecific and intraspecific F1 hybrids of Gossypium hirsutum and G. barbadense planted on two different dates was investigated. The interspecific crosses showed significant heterosis for percentage and time of germination, leaf number, and date of square formation when planted on the first planting date, and for plant height, LAI, and dry matter weight for both planting dates. The G. barbadense intraspecific cross exhibited a higher degree of heterosis than the G. hirsutum one for germination and dry matter weight when planted on the first planting date.The traits exhibiting significant estimates of heterosis for early planting, but not for late planting, were those associated with the early phases of plant growth. The differences stemming from planting dates were probably due to the low temperature that prevailed after the first planting, since the temperature after the second planting was close to the optimum. We concluded that F1 hybrids have greater phenotypic stability than their parents when confronted with varying temperature conditions. This condition probably results from their heterosis for seedling growth rate under suboptimal temperature regimes.

Effects of Silicic Acid Absorbed from the Surface of the Leaves upon the Paddy Rice Plant Growth

The experiment was made as to what would be the effect of silicic acid upon the growth of rice plants cultured without supply of silica, when it was applied through their leaf blades. The experiment was designed as follows: Plot non-Si: Rice plants were cultured without supply of silica. Plot spray: Na2SiO3 solution (0.1-0.2 ppm, Aug. 23-Sept. 27) was sprayed every other day on the surface of top of the rice plants cultured under the same conditions as rice plants of plot non-Si. Plot Si: Na2SiO3 was added in the culture solution. The results obtained were as follows: The rice plants of plot spray were superior to those of the other two plots in the following points; plant height, leaf number, stem number, panicle number, and dry matter weight at harvest time (fig. 1∼5). Contents and percentages of P2O5 in the whole plant and each of its organs (except its root) of plot spray were larger than in those of plot non-Si (fig. 7). Total N and P2O5 in the rice plant of plot spray were translocated to culms more smoothly than in those of plot non-Si, but not smoothly to panicles (fig. 6∼7). The serious differences of percentages of total N and K2O among three plots were not found (fig. 6, 8). The number of silicified cells in a leaf blade of the rice plant of plot spray was larger than that of the plant of plot non-Si (table 1), which proves that silica was absorbed in the leaves. Generally, the growth of the rice plant of plot spray were superior than that of the other two plots. The absorbtion of N, P, K through the roots of the rice plants of plot spray was easily; so was the translocation of N, P in the rice plants of plot spray. It is recognized that silicic acid absorbed from the surface of the leaf blade positively affected on the growth and physiological activity of the rice plant. It has need of silicic acid for the good growth of the rice plant.