scholarly journals Ovule development in Cycads: observation on anatomy and nucellus morphology in Zamia and Cycas

2019 ◽  
Author(s):  
Xin Zhang

AbstractIn the ovule evolution, the integument is the most attention point in discussion as a morphologic character of the seed plants. There are several theories and hypotheses about the origin of the integument were presented in the history. However, the development and function of the ovule envelopes are not so clear until now. The development of thehe basal gymnosperms Cycas and Zamia were to investigated, especially of the integument to complement the existing knowledge in seed plants. The development of ovules of seed plant is documented with morphological and anatomical using LM and SEM.The nucellar beak found in Zamia is a structure that has not been recorded previously. It protrudes from the micropyle at pollination and may be the primary acceptor for pollen. There are striking similarities to the lagenostom or salpinx in Lyginopteridatae. There may be an evolutionary way to interpret the pollination drop existing in the Lyginopteridatae. Probably the nucellar beak of Cycads, even Ginkgoales have the same function with the lagenostom or salpinx of the Lyginopteridatea. Unfortunately, pollen and transport inside the pollination chambers have not been observed. Further analysis of this unusual structure seems to be very important.

2009 ◽  
Vol 25 (1) ◽  
pp. 103-106 ◽  
Author(s):  
Nathan G. Swenson

Whole plant form and function vary spectacularly across the seed plants. In recent years, plant evolutionary ecologists have begun to document this diversity on large geographic scales by analysing ‘functional traits’ that are indicative of whole plant performance across environmental gradients (Swenson & Enquist 2007, Wright et al. 2004). Despite the high degree of functional diversity in tropical forests, convergence in function does occur locally along successional or light gradients (Bazzaz & Pickett 1980, Swaine & Whitmore 1988).


2020 ◽  
Vol 58 (1) ◽  
pp. 253-276 ◽  
Author(s):  
Dmitry Lapin ◽  
Deepak D. Bhandari ◽  
Jane E. Parker

The EDS1 family of structurally unique lipase-like proteins EDS1, SAG101, and PAD4 evolved in seed plants, on top of existing phytohormone and nucleotide-binding–leucine-rich-repeat (NLR) networks, to regulate immunity pathways against host-adapted biotrophic pathogens. Exclusive heterodimers between EDS1 and SAG101 or PAD4 create essential surfaces for resistance signaling. Phylogenomic information, together with functional studies in Arabidopsis and tobacco, identify a coevolved module between the EDS1–SAG101 heterodimer and coiled-coil (CC) HET-S and LOP-B (CCHELO) domain helper NLRs that is recruited by intracellular Toll-interleukin1-receptor (TIR) domain NLR receptors to confer host cell death and pathogen immunity. EDS1–PAD4 heterodimers have a different and broader activity in basal immunity that transcriptionally reinforces local and systemic defenses triggered by various NLRs. Here, we consider EDS1 family protein functions across seed plant lineages in the context of networking with receptor and helper NLRs and downstream resistance machineries. The different modes of action and pathway connectivities of EDS1 family members go some way to explaining their central role in biotic stress resilience.


2007 ◽  
Vol 168 (5) ◽  
pp. 751-761 ◽  
Author(s):  
Megan C. McCarthy ◽  
Brian J. Enquist ◽  
Andrew J. Kerkhoff

2018 ◽  
pp. 18-24
Author(s):  
V. Doronin ◽  
Yu. Kravchenko ◽  
V. Dryga ◽  
M. Budovsky ◽  
V. Doronin

In the intensive arable farming the productivity of sugar beets depends on many factors: soil-climatic conditions, introduction of highly productive hybrids, quality pre-sowing seed treatment, use of updated machinery and technologies, fertilizers, reliable plant protection, high technological processing at sugar mills and others. All the mentioned factors can reduce the productivity of sugar beets considerably, but it is not possible to reach a maximum potential of crop productivity without the use of good-quality seeds of the latest hybrids. The quality of sugar beet seeds is formed during the growth, and it depends on several factors, and first of all on the quality of mother root crops – their mass, sizes, turgor, disease damage and others. Laboratory trials were carried out at the Institute of bio-energy crops and sugar beets of Ukraine’s NAAS, field trials were carried out in the conditions of Ivanivka research-breeding station in the years of 2016–2018. The trial scheme envisaged the planting of root crops, which were not damaged with root rot and damaged with root rot, a focal point of rot being removed before planting. During vegetation, seed plants were treated with fungicides at a bud stage (one–time treatment) and at a bud stage and the beginning of flowering (two–time treatment). Fungicides were not used in the control. Mother root crops, seed plants and seeds of a sugar beet hybrid, developed on the basis of cytoplasm male sterility Romul, were the object of the research. In the field trials the following was determined: viability of the root crops (the number of the emerged crops as to the number of the panted root crops) and the seed plant density at a full emergence stage and before harvesting. Agro-biological evaluation of the seed plant condition was made before harvesting – the number of non-productive seed plants (dried, infertile ones and others), the number of disease-damaged plants and the degree of their development. A record plot area of one replication was 20 m2 in field trials, a fourfold replication. The technology of seed plant cultivation is conventional, in accordance with the recommendations of the Institute of bio-energy crops and sugar beets of Ukraine’s NAAS. The paper covered some peculiarities of the yield formation and the quality of sugar beet seeds, depending on the quality of mother root crops. It was proved that the use of the root crops, partially damaged with rot during storage, and even when a focal point of rot was removed before harvesting, had an effect on the root crop viability (which was by 4.4 % lower), the formation of more non-productive plants – by 1.6–1.8 times – due to the increase of prematurely dried plants and infertile ones, which resulted in a serious yield decease – by 0.09-0.13 t/ha and seed quality – viability by 4 % and emergence by 6 %, as compared with the variants where health root crops were planted. Two-time spraying of the seed plants with fungicides resulted in the increase of the yield capacity and the seed quality in the variants where only partially rot-damaged root crops were planted. A tendency to the increase of the mentioned indicators, both in the variants with healthy root crops planted and with partially damaged root crops planted, was recorded under one-time spraying of the seed plants with fungicides. The research of the seeds gathered from the seed plants, which were grown from the root crops, disease-damaged and healthy ones, confirmed the results of the field trials. The viability of the seeds, received from the healthy (not disease-damaged) root crops was higher by 9 %, emergence – by 5 %, as compared with the root crops, partially rot-damaged, focal points of which were removed before planting. Key words: mother root crops, rot, productive seed plants, yield capacity, viability, germination.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Upendo Lupanga ◽  
Rachel Röhrich ◽  
Jana Askani ◽  
Stefan Hilmer ◽  
Christiane Kiefer ◽  
...  

The V-ATPase is a versatile proton-pump found in a range of endomembrane compartments yet the mechanisms governing its differential targeting remain to be determined. In Arabidopsis, VHA-a1 targets the V-ATPase to the TGN/EE whereas VHA-a2 and VHA-a3 are localized to the tonoplast. We report here that the VHA-a1 targeting domain serves as both an ER-exit and as a TGN/EE-retention motif and is conserved among seed plants. In contrast, Marchantia encodes a single VHA-isoform that localizes to the TGN/EE and the tonoplast in Arabidopsis. Analysis of CRISPR/Cas9 generated null alleles revealed that VHA-a1 has an essential function for male gametophyte development but acts redundantly with the tonoplast isoforms during vegetative growth. We propose that in the absence of VHA-a1, VHA-a3 is partially re-routed to the TGN/EE. Our findings contribute to understanding the evolutionary origin of V-ATPase targeting and provide a striking example that differential localization does not preclude functional redundancy.


Rodriguésia ◽  
2015 ◽  
Vol 66 (4) ◽  
pp. 1085-1113 ◽  
Author(s):  
Daniela C. Zappi ◽  
Fabiana L. Ranzato Filardi ◽  
Paula Leitman ◽  
Vinícius C. Souza ◽  
Bruno M.T. Walter ◽  
...  

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora.


2014 ◽  
Vol 2 (2) ◽  
pp. 69 ◽  
Author(s):  
Neha Sharma ◽  
Pooja Gokhale Sinha ◽  
Ashok Kumar Bhatnagar

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