Development of open and closed leaf sheaths in Festuca trachyphylla and Festuca rubra (Poaceae)

1992 ◽  
Vol 70 (7) ◽  
pp. 1417-1428 ◽  
Author(s):  
Youqi Liu ◽  
Nancy G. Dengler
Keyword(s):  
Cross Sections ◽  
Leaf Development ◽  
Small Diameter ◽  
Leaf Sheath ◽  
Festuca Rubra ◽  
Ground Tissue ◽  
Longitudinal Splitting ◽  
Mature Leaves ◽  
Whole Plants ◽  
Important Character

The development of the leaf sheaths in two species of Festuca, subgenus Festuca, Festuca trachyphylla (Hackel) Krajina with open leaf sheaths and Festuca rubra L. s.l. with closed leaf sheaths is compared to determine the developmental basis of this taxonomically important character. In both species serial cross sections of seedlings, scanning electron microscopy, and dissections of whole plants showed that a short tubular leaf base is formed early during the second plastochron of leaf development. Later during the same plastochron, ligule formation delimits sheath and blade; at this stage, the tubular portion occupies about one-half (200 – 500 μm) of the incipient leaf sheath. Differential extension growth of the distal open portion and proximal closed section of the sheath results in the primarily open or closed sheaths that characterize the mature leaves of the two species. The longitudinal splitting of the tubular leaf sheath in a position opposite the midvein in F. rubra is anticipated by a zone of small-diameter cells within the ground tissue, but no other structural correlates of sheath mechanical strength and persistence were detected. Our observations indicate that subtle shifts in the distribution of growth during leaf expansion result in the contrasting character states exemplified by these two species. Key words: Festuca, grass leaf development, leaf sheath, Poaceae.

New morphological and anatomical data on the genus Fuernrohria (Apiaceae)

Phytotaxa ◽  
2020 ◽  
Vol 429 (1) ◽  
pp. 48-56
Author(s):  
BARIŞ BANİ ◽  
DUDU ÖZLEM MAVİ İDMAN
Keyword(s):  
Cross Sections ◽  
Leaf Sheath ◽  
Distribution Area ◽  
Morphological Description ◽  
Leaf Segment ◽  
Vascular Bundles ◽  
Anatomical Data ◽  
Micromorphological Characters ◽  
First Time ◽  
Stem Leaf

In this study, morphological and anatomical data (including fruit micromorphological characters) of the genus Fuernrohria were studied and compared with the related genera Grammosciadium, Caropodium and Vinogradovia. The morphological description of Fuernrohria setifolia, which is the only known species in the genus, is expanded. Photos of inflorescences, infructescences and leaves of the species taken from the wild are provided. Leaf segment and mericarps are illustrated, and also the distribution area of the genus is mapped. Anatomical features of root, stem, leaf sheath, leaf segment and fruit are presented with photographs of cross sections for each of them. Vegetative anatomical characteristics of the species and micromorphological description of fruit are given and exhibited for the first time in the present study. The results show that two important diagnostic characters for Fuernrohria are determined for the first time as “shape and size of commissural vittae in mericarps” and “number of vascular bundles in leaf cross section”.

scholarly journals Distribution of the endophytic fungi community in leaves of Bauhinia brevipes (Fabaceae)

2011 ◽  
Vol 25 (4) ◽  
pp. 815-821 ◽  
Author(s):  
Mariana Patrícia Amorim Hilarino ◽  
Fernando Augusto de Oliveira e Silveira ◽  
Yumi Oki ◽  
Leonardo Rodrigues ◽  
Jean Carlos Santos ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Host Plant ◽  
Endophytic Fungi ◽  
Leaf Development ◽  
Morphological Traits ◽  
Significant Contribution ◽  
Leaf Age ◽  
Mature Leaves ◽  
Tropical Biodiversity ◽  
Bauhinia Brevipes

Endophytic fungi represent large, yet unexplored components of biodiversity. This work evaluated the richness and the distribution of endophytes in the leaves of Bauhinia brevipes (Fabaceae). A total of 1110 colonies were recovered from the samples and grouped by their morphological traits into 126 taxa. The total number of taxa according to leaf development was: 102 in mature leaves, 93 in recently expanded leaves and 79 for unfolded leaves. The major endophyte genera were Phomopsis, followed by Dothiorella, Pestalotiopsis and Acremonium. The richness and the isolate numbers of endophytes were not statistically affected by leaf region. However, some taxa were leaf-age specific; six were isolated only from unfolded leaves, nine from recently expanded leaves and 17 were exclusively found in mature leaves. The composition of endophytes varied with leaf region; the similarities (Jaccard's Index) among the leaf regions of different leaf ages ranged from 0.36 to 0.46, indicating a high spatial variation in the community of endophytic fungi inside the leaves. The high richness of endophytes in this host plant highlights a significant contribution of fungi to tropical biodiversity and the need for further research in this area.

Leaf development in eight related grasses

1994 ◽  
Vol 123 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Y. Gao ◽  
D. Wilman
Keyword(s):  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Leaf Development ◽  
Festuca Arundinacea ◽  
Leaf Blade ◽  
Leaf Sheath ◽  
Leaf Expansion ◽  
Italian Ryegrass ◽  
Meadow Fescue ◽  
Rate Of Increase

SummaryLeaf development was studied in eight related grasses, grown in field swards cut at 5-week intervals, during the year of sowing and the subsequent year (1989 and 1990). The rate of leaf expansion was in the order Westerwolds ryegrass > Italian ryegrass (Lolium multiflorum), Italian ryegrass × meadow fescue > hybrid ryegrass > perennial ryegrass × meadow fescue, meadow fescue (Festuca pratensis), tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne). The order of grasses was similar, but not identical, for rate of leaf appearance, rate of leaf extension, weight of leaf blade emerging per shoot per week and rate of increase in length of exposed leaf sheath, and the order was approximately the reverse for weight per unit area of emerging leaf blade. The area per leaf blade increased greatly between May and October of the year of sowing, particularly in Westerwolds, Italian and hybrid ryegrasses and Italian ryegrass × meadow fescue. Area per leaf blade in tall fescue increased greatly between May and July of the year of sowing and May–July of the subsequent year. Rate of leaf expansion in meadow fescue was much higher in May of the year after sowing than in the previous May.

Losses of the digestible components of annual ryegrass (Lolium rigidum Gaudin) during senescence

1990 ◽  
Vol 41 (4) ◽  
pp. 719 ◽  
Author(s):  
RA Ballard ◽  
RJ Simpson ◽  
GR Pearce
Keyword(s):  
Chemical Composition ◽  
Leaf Blade ◽  
Leaf Sheath ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Stem Internode ◽  
Whole Plants ◽  
Grass Sward ◽  
Stem Leaf

Changes in the digestibility and chemical composition of a L. rigidum cv. Wimmera sward sown in May, 1985 were measured from 21 d pre-anthesis (9 Oct.) until 69 d after anthesis (7 Jan.) when the plants were dead. Max. yield of 11.7 t DM/ha was reached 8 d pre-anthesis. The in vitro DM digestibility (IVDMD) of whole plants decreased from 58% at anthesis to 36% 69 d after anthesis. This was associated with a decrease in the IVDMD of stem, leaf blades and sheaths. In the 3rd stem internode, which was considered representative of the stem, the loss of digestible yield was due to loss of DM soluble in neutral detergent (NDS). The NDS consisted mainly of non-structural carbohydrates. Similar losses of NDS contributed to loss of digestibility in the uppermost leaf blade and leaf sheath. The digestibility of NDS was generally 80-95% but in the leaf blade this declined to 45% as NDS was mobilized during leaf senescence. NDF digestibility of the stem declined from 35% at anthesis to 19% when dead; corresponding values for the uppermost leaf blade were 83 and 54%, resp., and for the leaf sheath 46 and 37%, resp. These characteristics of a senescing grass sward are discussed in relation to options for improving digestibility of dead grass pastures.

Sorbitol Versus Sucrose as Photosynthesis and Translocation Products in Developing Apricot Leaves

1985 ◽  
Vol 12 (6) ◽  
pp. 657 ◽  
Author(s):  
RL Bieleski ◽  
RJ Redgwell
Keyword(s):  
Leaf Development ◽  
Main Product ◽  
Mature Leaf ◽  
Young Leaf ◽  
Mature Leaves ◽  
Specific Transport ◽  
Young Leaves

Very young apricot leaves behave like the young leaves of most plants; that is, [14C]sucrose is formed as the main product of 14CO2 photosynthesis, and also when the leaves are supplied with [14C]glucose. [14C]sorbitol is not produced, and is poorly metabolized when fed to the leaf. Expanding leaves behave differently: [14C]sorbitol and [14C]sucrose are formed in similar amounts from both 14CO2 and [14C]glucose; and when [14C]sorbitol is supplied, it is readily metabolized and utilized for growth. Mature leaves are different again. They form [14C]sorbitol as the main product from 14CO2 and from [14C]glucose, and they do not metabolize [14C]sorbitol at all. Thus during development, apricot leaves gain but then lose the ability to utilize sorbitol. They also gain and keep the ability to synthesize sorbitol. This suggests that different biochemical paths exist for sorbitol formation and utilization, and that these paths are differently developed in the various stages of leaf development. Although the very young leaves did not synthesize sorbitol from CO2 or glucose, they contained it as their major sugar. Translocation behaviour was therefore studied. Neither the very young leaves nor the expanding leaves export any photosynthate, but the mature leaf rapidly translocates carbohydrate, mainly in the form of sorbitol, to the younger leaves as well as the rest of the plant. [14C]sorbitol supplied to the mature leaf can be recovered in that form from the very young leaf on the same shoot. This further establishes the role of sorbitol in apricot as a specific transport carbohydrate.

A dominant mutation in the maize homeobox gene, Knotted-1, causes its ectopic expression in leaf cells with altered fates

Development ◽  
1992 ◽  
Vol 116 (1) ◽  
pp. 21-30 ◽  
Author(s):  
L.G. Smith ◽  
B. Greene ◽  
B. Veit ◽  
S. Hake
Keyword(s):  
Leaf Development ◽  
Early Stage ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Vascular Bundles ◽  
Ground Tissue ◽  
Wild Type ◽  
Dominant Mutation ◽  
Coding Regions ◽  
Undifferentiated Cells

Dominant mutations of the Knotted-1 (Kn1) homeobox gene of maize alter the differentiation and growth of cells associated with leaf veins. By analyzing Kn1 transcripts and KN1 protein, we show that the gene is not expressed at high levels during the development of wild-type leaves. Instead, Kn1 is expressed in apical meristems of vegetative and floral shoots, and is downregulated as leaves and floral organs are initiated. Kn1 is also expressed in relatively undifferentiated cells within developing vascular bundles, as well as ground tissue, in immature, unelongated axes of wild-type vegetative and floral shoots. In Kn1-N2 mutant plants, quantitative, but not qualitative differences are apparent in Kn1 transcripts and KN1 protein, consistent with previous observations that dominant Kn1 mutations map to non-coding regions of the gene. Kn1 is expressed ectopically in vascular bundles within developing mutant leaves in a pattern that correlates with the phenotypic alterations produced by the Kn1-N2 mutation. Thus, Kn1 apparently alters the fates of leaf cells in which it is ectopically expressed from an early stage of leaf development. Based on these observations, we hypothesize that Kn1 functions in its wild-type context as a regulator of cell determination.

Histological analysis of direct organogenesis from micro-cross-sections of cultures of the banana

2006 ◽  
Vol 54 (6) ◽  
pp. 595 ◽  
Author(s):  
Jia Li ◽  
Xue-Lin Huang ◽  
Yue-Rong Wei ◽  
Xia Huang ◽  
Zhe Li ◽  
...  
Keyword(s):  
Cross Sections ◽  
Adventitious Shoots ◽  
Peripheral Zone ◽  
Leaf Sheath ◽  
Amino Acid Mixture ◽  
Direct Organogenesis ◽  
Acid Mixture ◽  
Murashige Skoog ◽  
Dividing Cells ◽  
Cell Layers

The histological origin of organogenesis was studied during plant regeneration of banana (Musa AAA cv. Williams) via direct organogenesis from micro-cross-sections of the rhizome in modified Murashige–Skoog (MS) medium (including 10 µm 6-BAP, 1 µm IAA and 50 µm KN). The frequency of the organogenesis was dependent on the position from where the explant was cut. Generally, more adventitious shoots were obtained from explants cut from regions close to apical meristem. The origin of adventitious shoots was multicellular, from cell layers with active cell division in the epidermis of the rhizome axis. After 24 h of culture, a layer of epidermal cells close to the leaf sheath base was actively dividing, and as the time in culture increased, regions containing actively dividing cells became enlarged. By the fifth day of culture, regions of actively dividing cells covered the whole peripheral zone of cortex. Several meristemoid structures were formed from the peripheral zone of cortex after 7 days of culture. These structures developed into adventitious shoots by the ninth day of culture. Vigorous plantlets could be regenerated from the shoots when they were transferred to rooting medium containing MS basal salts supplemented with 30 g L–1 sucrose, 6.5 g L–1 agar, a vitamin/amino acid mixture, 1 µm NAA and 1 µm 6-BAP.

Trichome density and its protective potential against ultraviolet-B radiation damage during leaf development

1995 ◽  
Vol 73 (3) ◽  
pp. 376-383 ◽  
Author(s):  
George Karabourniotis ◽  
Dimitris Kotsabassidis ◽  
Yiannis Manetas
Keyword(s):  
Radiation Damage ◽  
Leaf Development ◽  
Leaf Age ◽  
Ultraviolet B ◽  
Eriobotrya Japonica ◽  
Trichome Density ◽  
Cydonia Oblonga ◽  
Leaf Hairs ◽  
Ultraviolet B Radiation ◽  
Mature Leaves

Trichome density and the capacity of leaf hairs to protect underlying tissues against ultraviolet-B radiation damage were assessed during leaf development in three tree species. In all cases, trichome density and the relative quantities of ultraviolet radiation absorbing phenolic constituents (expressed on a leaf area basis) declined considerably with leaf age. In addition, the percent leaf dry mass invested in trichome decreased significantly. Reductions were greater on the adaxial leaf surface, leading to an almost glabrous upper epidermis in mature leaves. Internal (i.e., leaf total minus trichome) phenolics showed no significant changes with leaf age in Eriobotrya japonica and Cydonia oblonga. In Olea europaea, however, the concentration of internal phenolics was doubled in mature leaves. Ultraviolet-B radiation resulted in a reduction of photosystem II photochemical efficiency and extensive epidermal browning only in young, dehaired leaves. No such effects were observed in young, dehaired leaves in the absence of ultraviolet-B radiation or in normal young or mature ultraviolet-B-irradiated leaves. It is suggested that the dense trichomes often covering young leaves may, in addition to other functions, protect transiently the underlying cells against ultraviolet-B radiation damage during the time period required for the maturation of internal avoidance and (or) repairing mechanisms. Key words: Cydonia oblonga, Eriobotrya japonica, Olea europaea, leaf development, leaf hairs, phenolics, ultraviolet-B radiation damage.

Temporal and spatial distribution of BN28 during low temperature acclimation of Brassica napus cv. Cascade seedlings

1997 ◽  
Vol 75 (1) ◽  
pp. 28-35
Author(s):  
Mitchel D. de Beus ◽  
Anne M. Johnson-Flanagan ◽  
Joseph G. Boothe
Keyword(s):  
Brassica Napus ◽  
Low Temperature ◽  
Leaf Age ◽  
Temporal Distribution ◽  
Leaf Tissue ◽  
Temperature Acclimation ◽  
Ground Tissue ◽  
Temporal And Spatial Distribution ◽  
Apical Meristems ◽  
Mature Leaves

The objective of this study was to determine the spatial and temporal distribution of the peptide BN28 in Brassica napus cv. Cascade seedlings during low temperature acclimation. Immunoblots revealed that BN28 was present in leaves and shoot apical meristems of plants grown under low temperature but was absent from older tissues in the stem. Immunocytochemistry was used to determine the distribution throughout leaf and apical meristem tissues. BN28 was found throughout the apical meristems, was localized in the ground tissue and epidermis of young leaves, and was restricted to the ground tissue and guard cells in mature leaves. Differences in total accumulation were also noted, with the youngest leaves having the highest accumulation of BN28 and the quantity decreasing with leaf age. Despite these differences, plant developmental stage did not affect the accumulation of BN28 in individual leaves. Post-transcriptional controls are expected to regulate accumulation of the protein, as bn28 mRNA accumulates during acclimation in both young and mature leaves. Immunolocalization studies of BN28 in acclimated leaf tissue confirmed that BN28 is cytoplasmically localized and has no apparent weak association with organelles or other cellular membrane systems. Key words: acclimation, Brassica, development, immunocytochemistry, low temperature, protein synthesis.

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