Organography and Plant Histology of Salvinia molesta (Salviniaceae)

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(Edited)

As usual, I would like to start by extending a warm greeting to all users of the #Hive platform, especially my friends from the @STEMsocial team. I would like to express that, despite the impossibility of going to the field to make plant collections and in situ determinations, or going to the Agricultural Botany laboratory to make cuts, identify and describe histological segments, activities that in the current circumstances cannot be done due to the strict isolation and confinement measures decreed by Covid-19 in the Southern Zone of Lake Maracaibo. However, with this entry I want to take up again the contributions on Organography and plant histology, so the manuscript was developed mainly from taxonomic descriptors of organographic character..


Introduction


Salvinia molesta, they are located in the group of Aquatic Macrophytes, it belongs to the genus Salvinia and family Salviniaceae, these vegetal specimens are characterized for being covered by structures in form of velvety hairs, on the other hand, it is important to point out that at global scale 12 species of the genus Salvinia have been reported, namely; S. molesta, S. auriculata, S. rotundifolia, S. biloba, S. cucullata, S. hastata, S. herzogii, S. martynii, S. natans, S. nymphellula, S. oblongifolia and S. minimos.

Of the previously mentioned specimens, Salvinia molesta is the most studied at an ecological level, mainly because, this Aquatic Macrophyte usually causes infestation problems in water bodies, however, in the last decade researches have been developed with the objective of verifying the hydrophobic and absorbent potential of this aquatic vegetal material, for the extraction of polluting hydrocarbons.

Consequently, and based on the multiple in situ tests where Salvinia molesta has been used in the cleaning of oil spills, the objective of this post is to describe the organographic and histological characteristics, and the main hydrophobic and absorbent properties of this valuable biological resource.


Biological classification


Kingdom: Plantae
Division: Pteridophyta
Class: Pteridopsida
Orde: Salviniales
Family: Salviniaceae
Gender: Salvinia
Species: molesta

Common names

In most countries in South America Salvinia molesta is known as "Water Accordion", however, in Brazil it is identified as Giant Salvinia, or Kariba weed.


Hydrophobic and absorbent potential


It has been indicated, that Salvinia molesta is one of the few aquatic Macrophytes with capacity to float freely on the bodies of water, this due to the internal air chambers of its macrostructures in form of velvety hairs, that exhibit the vegetative segments of this vegetal material, morphological element that offers hydrophobic and absorbent potential.

Fig. 2 Salvinia molesta exhibits macro-structures in the form of velvety hairs with hydrophobic and absorbent capacity. Public domain image Author: Wilhelm Barthlott, 2020 / CC BY-SA 4.0

It is important to emphasize that these velvety macrostructures are made up of absorbent tissue, which is why, from the biological point of view, the use of Salvinia molesta is being considered as a viable solution in the decontamination of water bodies that suffer from hydrocarbon spills, basically because of its capacity to effectively repel water and because of the potential of its trichomes to trap the drops or corpuscles that form the crude oil.

Fig. 3 The macrostructures in the form of velvety hairs of Salvinia molesta, have the capacity to trap the drops or corpuscles that form the crude oil. Public domain image Author: Patrice, 2018 / CC BY-SA 2.0


Origin and distribution


Salvinia molesta is native to southeast Brazil, and was first observed outside its natural range in the Democratic Socialist Republic of Sri Lanka in 1939, and has since become an invasive plant in more than 20 countries including Australia, New Zealand, Fiji, India, Indonesia, Malaysia, the Philippines, Singapore, and Papua New Guinea. It has also been reported to affect wetlands in African countries such as the Republic of Ivory Coast, Ghana, Zambia, Kenya, Namibia, Botswana, South Africa, and Madagascar. In the particular case of South America and the Caribbean, this waterborne bug has infected water bodies in Colombia, Guyana, Cuba, and Trinidad.

Fig. 4 Salvinia molesta exhibits vegetative structure in the form of velvety hairs. Public domain image Author: Francesco Cervoni, 2016 / CC BY-SA 4.0


Botanical description


Way of life

The aquatic specimens of "Water Accordion", as Salvinia molesta is widely known, are water ferns that float freely, this because, each pair of fronds that occur in each knot of the stem, have the ability to float just below the submerged leaves.

Fig. 5 Salvinia molesta is a free-floating water fern. Public domain image Author: Forest and Kim Starr, 2010 / CC BY-SA 3.0

Root

It exhibits a radical system of filiform segments, with secondary and tertiary roots, which gives it the ability to establish itself on the water sheets.

Stem

It has cylindrical and horizontal sandstone stems (tissues with abundant intercellular spaces).

Leaf

Fig. 6 Salvinia molesta exhibits frond-like leaves and trichomes. Public domain image Author: Issempa, 2013 / CC BY-SA 3.0

The specimens of Salvinia molesta, present leaves type fronds, of light green color, rounded, with trichomes in the form of white hairs, and in verticilated disposition.

Sporocarp

The sporocarp of Salvinia molesta, has a pluricellular reproductive structure of oval morphology, with capacity to produce vegetative spores.


Reproduction


Sexual reproduction

It is believed that Salvinia molesta, reproduces sexually because it produces carpophore spores, but they are rarely found and when they are present, these spores are usually not viable.

Asexual reproduction

It is proposed, that the reproduction of Salvinia molesta is only asexual, that is vegetative, by means of the breakage of the rhizomes of the plants, that make arise daughter plants from new yolks.

Fig. 7 It is proposed that the reproduction of Salvinia molesta exclusively asexual. Public domain image Author: Vengolis, 2015 / CC BY-SA 4.0


Growth


Specimens of Salvinia molesta, are much smaller compared to other invasive aquatic macrophytes such as E. crassipes, however, presents a higher growth rate, under optimal conditions, allows doubling in number and biomass in less than 3 days.


Ecology


Salvinia molesta is adapted to lakes and rivers with little movement, is considered an invasive aquatic macrophyte, mainly by its excessive growth, an element that prevents the penetration of light in the water sheets, as a result of the formation of very dense layers of biomass.

Fig. 8 Generally Salvinia molesta grows in lakes and rivers with little movement. Public domain image Author: Jensen K, 2012 / CC BY-SA 3.0

This excessive growth of biomass, which exhibits Salvinia molesta brings problems of oxygenation in the water bodies, which generates the death of fish, on the other hand, this aquatic macrophyte causes disadvantages to the lacustrine transport, reduces the quality of the water and the aesthetic values, besides obstructing the takings of irrigation and generation of energy, also are known problems of public health associated with the excessive proliferation of specimens of Salvinia molesta.


Histology and organography


I would have liked to present a detailed histological description of Salvinia molesta, as outlined in the previous contributions, but unfortunately the institutional closure of the laboratory of Agricultural Botany of UNESUR, product of the isolation and confinement by Covid-19 made it impossible to comply with this procedure.

In this sense, and a little bit to not stop socializing the internal characteristics of Salvinia molesta, it is to manifest that, according to rigorous procedures of identification and histological description, the leaves type fronds in submerged condition exhibit smaller parenchymal cells in comparison with the floating fronds, both of elongated ellipsoidal morphology, while the epidermal structure of the floating fronds, presents adaxial surface with stomas of simple structure, and abaxial surface without stomas and cuticle.


SCIENTIFIC CONTRIBUTIONS OF THIS PUBLICATION


  • The socialized content, was outlined with the purpose of presenting in the platform #Hive information of taxonomic and organographic character, biological and ecological characteristics, besides the hydrophobic and absorbent potentialities, that have the vegetative segments of the specimens of Salvinia molesta, in the constant search for divulging manuscripts of technical-scientific utility.


BIBLIOGRAPHICAL REFERENCES CONSULTED AND CITED:


[1] Hussner A., and Netherlands M. Salvinia molesta D.S. Mitch. Bulletin. 2017; 47; 3: 1 - 6. Article: Online access

[2] Olivers D. A Review of the Biology of Giant Salvinia (Salvinia molesta Mitchell). J. Aquat. Plant Manage. 1993; 31: 227 – 231. Article: Online access

[3] McFarland D., Nelson L., Grodowitz M., Smart M., and Owens C. Salvinia molesta D. S. Mitchell (Giant Salvinia) in the United States: A Review of Species Ecology and Approaches to Management. Aquatic Plant Control Research Program. 2004; 41. Article: Online access

[4] Kau R. Anatomical Observations on Floating Leave. Faculty Publications in the Biological Sciences. 1976; 461. Article: Online access

[5] Vasco A., Moran R., and Ambrose B. The evolution, morphology, and development of fern leaves. Front Plant Sci. 2013; 4: 345. Article: Online access


ATTENTION

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OBSERVATION

The cover image was designed by the author: @lupafilotaxia, incorporating the public domain background image, Author: Issempa, 2013, 2008 / CC BY-SA 4.0.





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5 comments
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That's an interesting looking plant and it seems it is limited in distribution. I hope the covid situation can ease off soon so that we can learn more about histology and organography.

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(Edited)

Greetings friend @gentleshaid

It is widespread here in South America, mainly in countries such as Brazil, Colombia and Venezuela. In recent years it has been attracting the interest of the oil sector, as it is used to clean up rivers that have suffered oil spills.

The pandemic in this area has alarming figures, on the other hand, the health system is not working, the situation in these first two weeks of 2021 has worsened.

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