scholarly journals Origin of the outer integument and its implication for the angiosperm evolution

2004 ◽  
Vol 16 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Toshihiro Yamada
Keyword(s):  
Outer Integument ◽  
Angiosperm Evolution

scholarly journals 4-CPA (4-Chlorophenoxyacetic Acid) Induces the Formation and Development of Defective “Fenghou” (Vitis vinifera × V. labrusca) Grape Seeds

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 515
Author(s):  
Zhenhua Liu ◽  
Yan Wang ◽  
Wenjiang Pu ◽  
Haifeng Zhu ◽  
Jinjun Liang ◽  
...  
Keyword(s):  
Vitis Vinifera ◽  
Outer Integument ◽  
Underlying Mechanism ◽  
Grape Seeds ◽  
Endosperm Tissue ◽  
Seed Shape ◽  
Seed Formation ◽  
Significant Difference ◽  
Fruit Setting ◽  
Chlorophenoxyacetic Acid

For some horticultural plants, auxins can not only induce normal fruit setting but also form fake seeds in the induced fruits. This phenomenon is relatively rare, and, so far, the underlying mechanism remains unclear. In this study, “Fenghou” (Vitis vinifera × V. labrusca) grapes were artificially emasculated before flowering and then sprayed with 4-CPA (4-chlorophenoxyacetic acid) to analyze its effect on seed formation. The results show that 4-CPA can induce normal fruit setting in “Fenghou” grapes. Although more seeds were detected in the fruits of the 4-CPA-treated grapevine, most seeds were immature. There was no significant difference in the seed shape; namely, both fruit seeds of the grapevines with and without 4-CPA treatment contained a hard seed coat. However, the immature seeds lacked embryo and endosperm tissue and could not germinate successfully; these were considered defective seeds. Tissue structure observation of defective seeds revealed that a lot of tissue redifferentiation occurred at the top of the ovule, which increased the number of cell layers of the outer integument; some even differentiated into new ovule primordia. The qRT-PCR results demonstrated that 4-CPA application regulated the expression of the genes VvARF2 and VvAP2, which are associated with integument development in “Fenghou” grape ovules. Together, this study evokes the regulatory role of 4-CPA in the division and continuous redifferentiation of integument cells, which eventually develop into defective seeds with thick seed coats in grapes.

Seed morphology and ultrastructure in Citrus garrawayi (Rutaceae) in relation to germinability

2007 ◽  
Vol 55 (6) ◽  
pp. 618 ◽  
Author(s):  
Kim N. Hamilton ◽  
Sarah E. Ashmore ◽  
Rod A. Drew ◽  
Hugh W. Pritchard
Keyword(s):  
Moisture Content ◽  
Seed Size ◽  
Seed Coat ◽  
Outer Integument ◽  
Dry Weight ◽  
Seed Morphology ◽  
Embryonic Axis ◽  
Morphological Development ◽  
Seed Moisture Content ◽  
Immature Seeds

Combinational traits of seed size and seed-coat hardness in Citrus garrawayi (F.M.Bailey) (syn. of Microcitrus garrowayi) were investigated as markers for estimation of seed morphological and physiological maturity. Seed size (length) and coat hardness correlated well with changes in seed coat and embryo morphological development, dry-weight accumulation, decreases in moisture content and a significant increase in germinability. Seed moisture content decreased from 82 ± 1% in immature seeds to 40 ± 1% at seed maturation. The outer integument of immature seeds consisted of thin-walled epidermal fibres from which outgrowths of emerging protrusions were observed. In comparison, mature seed coats were characterised by the thickening of the cell walls of the epidermal fibres from which arose numerous protrusions covered by an extensive mucilage layer. Immature seeds, with incomplete embryo and seed-coat histodiffereniation, had a low mean germination percentage of 4 ± 4%. Premature seeds, with a differentiated embryonic axis, were capable of much higher levels of germination (51 ± 10%) before the attainment of mass maturity. Mature seeds, with the most well differentiated embryonic axis and maximum mean dry weight, had the significantly highest level of germination (88 ± 3%).

scholarly journals Fossil evidence for low gas exchange capacities for Early Cretaceous angiosperm leaves

Paleobiology ◽  
2011 ◽  
Vol 37 (2) ◽  
pp. 195-213 ◽  
Author(s):  
Taylor S. Feild ◽  
Garland R. Upchurch ◽  
David S. Chatelet ◽  
Timothy J. Brodribb ◽  
Kunsiri C. Grubbs ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Early Cretaceous ◽  
Leaf Gas Exchange ◽  
Exchange Capacity ◽  
Basal Angiosperm ◽  
Photosynthetic Gas Exchange ◽  
Angiosperm Evolution ◽  
Early Angiosperm ◽  
Fossil Evidence ◽  
Functional Analyses

The photosynthetic gas exchange capacities of early angiosperms remain enigmatic. Nevertheless, many hypotheses about the causes of early angiosperm success and how angiosperms influenced Mesozoic ecosystem function hinge on understanding the maximum capacity for early angiosperm metabolism. We applied structure-functional analyses of leaf veins and stomatal pore geometry to determine the hydraulic and diffusive gas exchange capacities of Early Cretaceous fossil leaves. All of the late Aptian—early Albian angiosperms measured possessed low vein density and low maximal stomatal pore area, indicating low leaf gas exchange capacities in comparison to modern ecologically dominant angiosperms. Gas exchange capacities for Early Cretaceous angiosperms were equivalent or lower than ferns and gymnosperms. Fossil leaf taxa from Aptian to Paleocene sediments previously identified as putative stem-lineages to Austrobaileyales and Chloranthales had the same gas exchange capacities and possibly leaf water relations of their living relatives. Our results provide fossil evidence for the hypothesis that high leaf gas exchange capacity is a derived feature of later angiosperm evolution. In addition, the leaf gas exchange functions of austrobaileyoid and chloranthoid fossils support the hypothesis that comparative research on the biology of living basal angiosperm lineages reveals genuine signals of Early Cretaceous angiosperm ecophysiology.

scholarly journals Ontogenia de la semilla de Yucca periculosa (Agavaceae)

2017 ◽  
pp. 5
Author(s):  
Eduardo García-Villanueva ◽  
E. Mark Engleman
Keyword(s):  
Cell Wall ◽  
Embryo Development ◽  
Seed Coat ◽  
Outer Integument ◽  
Triangular Prism ◽  
Seed Shape ◽  
Food Reserve ◽  
Seed Maturity ◽  
Nuclear Development ◽  
Black Color

Seeds of several Yucca species have been studied by Arnott and Horner. They mainly studied the nature condition and stated that the extra-embryonic food reserve tissue is a perisperm. This paper provides ontogenic evidence that this tissue is an endosperm with nuclear development type. The seed shape is nearly a triangular prism less than 1 cm long, black color and the raphe groove is conspicuous. The seed coat is derived exclusively from the outer integument. The exotesta external periclinal cell wall appears with irregular thickness. Both mesotesta and endotesta grow irregularly inward the seed confering to the endosperm a ruminate appearance. Toward seed maturity, the inner integument tissues disappear, thus fusion between intertegumentary and tegmen-nucellar cuticles occurs; valuable ontogenic information is showed by the cuticles, due to its persistence in spite of its generative tissue disappearance. The embryo development increases until 10 weeks after anthesis, it is cylindric, folds like "S" and two thirds of its chalazal lenght correspond to the cotyledon.

Oxygen and environmental stress in plants: and evolutionary context

1994 ◽  
Vol 102 ◽  
pp. 155-165 ◽  
Author(s):  
George A. F. Hendry
Keyword(s):  
Oxidative Stress ◽  
Free Radical ◽  
Environmental Stress ◽  
Angiosperm Evolution ◽  
Selective Pressures ◽  
The Past ◽  
Wide Range ◽  
Evolutionary Context ◽  
Radical Processes ◽  
Oxidative Attack

SynopsisContemporary plant species show a wide range of responses to oxidative attack. Much of this variation may reflect the different environmental selective pressures operating at different geological periods over the course of angiosperm evolution. Evidence is provided to show that the wide range of contemporary responses to oxidative stress may directly reflect the persistence of genes controlling free radical processes under environments of the past.

SUPERMAN attenuates positive INNER NO OUTER autoregulation to maintain polar development of Arabidopsis ovule outer integuments

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4281-4289
Author(s):  
Robert J. Meister ◽  
Louren M. Kotow ◽  
Charles S. Gasser
Keyword(s):  
De Novo ◽  
Outer Integument ◽  
Negative Regulator ◽  
Sufficient Information ◽  
Coding Region ◽  
Adaxial Side ◽  
Abaxial Side ◽  
Protein Coding ◽  
Plant Parts ◽  
Reporter Gene Analysis

The outer integument of Arabidopsis ovules exhibits marked polarity in its development, growing extensively from the abaxial side, but only to a very limited extent from the adaxial side of the ovule. Mutations in two genes affect this asymmetric growth. In strong inner no outer (ino) mutants outer integument growth is eliminated, whereas in superman (sup) mutants integument growth on the adaxial side is nearly equal to wild-type growth on the abaxial side. Through complementation and reporter gene analysis, a region of INO 5′-flanking sequences was identified that contains sufficient information for appropriate expression of INO. Using this INO promoter (P-INO) we show that INO acts as a positive regulator of transcription from P-INO, but is not sufficient for de novo initiation of transcription in other plant parts. Protein fusions demonstrate nuclear localization of INO, consistent with a proposed role as a transcription factor for this member of the YABBY protein family. Through its ability to inhibit expression of the endogenous INO gene and transgenes driven by P-INO, SUP is shown to be a negative regulator of INO transcription. Substitution of another YABBY protein coding region (CRABS CLAW) for INO overcomes this negative regulation, indicating that SUP suppresses INO transcription through attenuation of the INO positive autoregulatory loop.

Sign in / Sign up

Export Citation Format

Share Document