Diversity of cell lengths in intercalary meristem regions of grasses: location of the proliferative cell population

Intercalary meristems are responsible for the production of the majority of cells in stems. The overall objective of the present study was to determine (i) the boundaries of the proliferative parenchyma cells in the intercalary meristems and (ii) the proliferative capacity of cells in the intercalary meristems in stems of a species of Bambusa Schreb. (bamboo), Phragmites australis (Cav.) Trin. ex Steud., Triticum aestivum L., and Zea mays L. Data show that lengths of parenchyma cells within proliferative portions of intercalary meristems were not the same for all intercalary meristems of a species. Lengths of elongated parenchyma cells in internodes were relatively similar among internodes of a species, but lengths of elongated parenchyma cells in internodes were not similar among the four grass species tested. For example, cell lengths of elongated parenchyma cells in internodes of P. australis ranged from 14.8 to 23.0 µm, very different from lengths of elongated cells in Bambusa sp. (69.175.4 µm). The number of proliferative cells in most files of intercalary meristems of Bambusa was less than 15. For many of the intercalary meristems of P. australis, the intercalary meristem consisted of 1025 cells in each file. Fourth intercalary meristems of T. aestivum and Z. mays consisted of 20 and 25 cells in files, respectively. Data showed that none of the cell populations of the intercalary meristems of four species exhibited an exponential cell length distribution. In general, less than half of the 10 groups of cells had percentages of cells that resembled an exponential cell-age distribution. These data lead to the conclusion that not all parenchyma cells of intercalary meristems are rapidly proliferating. Also, potentially prolifera tive cells (short cells) of the intercalary meristems may not be localized into a specific zone but are more scattered throughout the nodal region.Key words: intercalary meristems, proliferative cell populations, Gramineae, cell lengths.

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The dynamics of continuous microbial culture described by cell age distribution and concentration of one substrate

Bulletin of Mathematical Biology ◽

10.1007/bf02458270 ◽

1994 ◽

Vol 56 (5) ◽

pp. 837-862 ◽

Cited By ~ 4

Author(s):

I. G. Minkevich ◽

A. Yu. Abramychev

Keyword(s):

Age Distribution ◽

Microbial Culture ◽

Cell Age

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Bias in Using an Age–Length Key to Estimate Age-Frequency Distributions

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-030 ◽

1978 ◽

Vol 35 (2) ◽

pp. 184-189 ◽

Cited By ~ 36

Author(s):

S. J. Westrheim ◽

W. E. Ricker

Keyword(s):

Frequency Distribution ◽

Age Distribution ◽

Length Distribution ◽

Fish Population ◽

Systematic Bias ◽

Parental Age ◽

Frequency Distributions ◽

Class Strength ◽

Key Words Age ◽

Age Frequency Distribution

Consider two representative samples of fish taken in different years from the same fish population, this being a population in which year-class strength varies. For the "parental" sample the length and age of the fish are determined and are used to construct an "age–length key," the fractions of the fish in each (short) length interval that are of each age. For the "filial" sample only the length is measured, and the parental age–length key is used to compute the corresponding age distribution. Trials show that the age–length key will reproduce the age-frequency distribution of the filial sample without systematic bias only if there is no overlap in length between successive ages. Where there is much overlap, the age–length key will compute from the filial length-frequency distribution approximately the parental age distribution. Additional bias arises if the rate of growth if a year-class is affected by its abundance, or if the survival rate in the population changes. The length of the fish present in any given part of a population's range can vary with environmental factors such as depth of the water; nevertheless, a sample taken in any part of that range can be used to compute age from the length distribution of a sample taken at the same time in any other part of the range, without systematic bias. But this of course is not likely to be true of samples taken from different populations of the species. Key words: age–length key, bias, Pacific ocean perch, Sebastes alutus

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Sistemas de cultivo e características do solo afetando a estabilidade de agregados

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06831998000200017 ◽

1998 ◽

Vol 22 (2) ◽

pp. 311-317 ◽

Cited By ~ 36

Author(s):

I. F. Silva ◽

J. Mielniczuk

Keyword(s):

Triticum Aestivum ◽

Zea Mays ◽

Glycine Max ◽

Zea Mays L ◽

Triticum Aestivum L ◽

Digitaria Decumbens ◽

Glycine Max L ◽

Macroptilium Atropurpureum

Em um Latossolo Roxo de Santo Ângelo (RS), e em um Podzólico Vermelho-Escuro de Eldorado do Sul (RS), ambos com textura argilosa, submetidos o primeiro à exploração com cultivo convencional de trigo (Triticum aestivum L.) e soja (Glycine max L.) e sob setária (Setaria anceps L.), e o segundo à exploração com capim-pangola (Digitaria decumbens L.), siratro (Macroptilium atropurpureum L.), plantio direto com aveia (Avena bizantina L.)/milho (Zea mays L.) e área sem vegetação, foi realizado o presente trabalho durante a safra de verão (1990/1991), com o objetivo de avaliar a estabilidade e a agregação do solo sob diferentes sistemas de cultivo. Constatou-se, nessa avaliação, que as gramíneas perenes por meio do seu sistema radicular tiveram grande efeito na agregação e estabilidade dos agregados do solo e que os teores de carbono orgânico, de ferro e alumínio-oxalato, argila e grau de dispersão tiveram também efeitos na agregação do solo, porém insuficientes para explicar as variações entre o diâmetro médio ponderado dos agregados sob os diferentes sistemas de cultivo.

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Comparative Population Growth of the Psocid Liposcelis yunnaniensis (Psocoptera: Liposcelididae) on Different Diets

International Journal of Insect Science ◽

10.4137/ijis.s4590 ◽

2010 ◽

Vol 2 ◽

pp. IJIS.S4590 ◽

Cited By ~ 2

Author(s):

M.W. Hassan ◽

W. Dou ◽

H.B. Jiang ◽

J.J. Wang

Keyword(s):

Triticum Aestivum ◽

Population Growth ◽

Avena Sativa ◽

Zea Mays L ◽

Triticum Aestivum L ◽

Artificial Diets ◽

Relative Level ◽

Rice Hulls ◽

Hulled Barley ◽

Comparative Population

In this study, we investigated the population growth of the Liposcelis yunnaniensis (Psocoptera: Liposcelididae) feeding on ten different diets. Out of the ten diets, eight were made of plain cereals namely wheat ( Triticum aestivum L.), corn ( Zea mays L.), barley ( Hordeum vulgar L.), oats ( Avena sativa L.), rice ( Oryza sative L.), and sorghum ( Sorghum bicolour L.) while two were the artificial diets named Nayak wheat diet and Universal diet. The population growth was recorded as corn > wheat > universal diet > hulled barley > rice (hulls intact) > barley (hulls intact) > sorghum > Nayak wheat diet > oats > hulled rice. After 32 d culture, the initial 5 psocids developed to the populations as 41.8 ± 4.26, 41.5 ± 4.09 and 39.1 ± 7.64 on corn, wheat and universal diet, respectively. Meanwhile, psocids feeding on Nayak wheat diet, oats and hulled rice had significantly lower populations with 25.6 ± 2.42, 22.5 ± 3.09 and 13.6 ± 2.36 respectively. Rice and barley were included in the diets with and without hulls to see their effect on population growth. In case of barley, hulls had no significant effect on population growth while rice with hulls had significantly higher populations than rice alone. This study has confirmed the relative level of suitability of different cereals for this species when damaged. We have described a method to get the uniform age adults that can be helpful in research experiments.

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