With this new delivery, I resume the manuscripts on organography and plant histology, this time I will share with all users of the HIVE platform and especially with lovers of botanical content, descriptive information of the species Cucurbita maxima (CUCURBITACEAE) with the firm intention of contributing to the dissemination of scientific-technical and nutritional elements of this important plant resource.
Introduction
Cucurbita maxima, is a species of herbaceous biotype of climbing category, this vegetal resource belonging to the family of the Cucurbitaceae, is widely consumed in North America and South America, this because, its edible fruits contain sources of macros and essential micronutrients for the feeding [1].
The availability of macros and micronutrients, which have the organographic structures of Cucurbita maxima, has been throughout history the main reason for its agricultural domestication, particularly by the high percentage of carbohydrates available in the mesocarp of its fruits, in addition to the oil and protein content in the seeds [2].
Consequently, starting from the botanical and utilitarian foundations shown by the Cucurbita maxima, the aim of this post is to describe the organographic and histological characteristics and food properties of this important biological resource.
Biological classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Orde: Cucurbitales
Family: Cucurbitaceae
Gender: Cucurbita
Species: maxima
Common names
In the particular case of Venezuela a Cucurbita maxima, is distinguished as Auyama, however, in the rest of the countries of North, Central and South America it is usually identified as Squash.
Food properties
According to information reported by the FAO, the Cucurbita maxima is widely cultivated, not only for its agronomic viability and economic profitability, but also for the nutritional contributions and safety offered by its fruits [4].
It is estimated that the fruits of Cucurbita maxima, have acceptable nutritional properties with carbohydrate values above 10%, protein 15%, in addition to vitamin A, minerals and fiber, without ignoring the high proportion of water reported in 90% of total weight, a beneficial element for healthy intake [5].
These nutritional properties, places the fruit of Squash Cucurbita maxima, as a high quality food that can be consumed in fresh state, dehydrated or after having been submitted to cooking, gastronomically in Venezuela it is used in the preparation of soups, cakes, creams and desserts, additionally flours can be elaborated in the search of prolonging the durability of its biomass.
Besides the fruit, the seeds of Squash Cucurbita maxima, as they have considerable lipid values, are appreciated by the oilseed industries for oil extraction, essential fatty acid values estimated at 40% of the total dry weight of seeds of C. maxima have been reported [5].
Origin and distribution
The Cucurbita maxima, originates from the American continent, specifically from Central America, with an extensive tropical and subtropical distribution. It can be established geographically in temperate latitudes due to its characteristics of ecological adaptability [2].
Botanical description
Way of life
The Squash, as it is designated in Venezuela, has a biotype of herbaceous condition and annual.
Root
he species Cucurbita maxima, develops relatively thick pivot roots, and adventitious roots at the vegetative nodes of the stem.
Stem
It has cylindrical, semi-upright and climbing stems, which emit vegetative tendrils of helical morphology and phytomechanical, which allow it to prostrate on various physical structures.
Leaf
Cucurbita maxima, has simple petiole insertion leaf blades, with reniform morphology, lobed edge, accumulated apex, sagittal base, webbed rib, alternate phyllotaxy and depigmented segments.
Flower
The flowers are monoic (both sexes in the same individual), with floral units of yellow coloration, pentameras and corolla of flared morphology, biologically they present dehiscence in the first hours of the day.
Fruit
The Squash, exhibits big fruits type berry of ovarian ínfera formation, of fleshy mesocarp and rounded to elliptical morphology.
Seeds
Cucurbita maxima, has seeds with an oval appearance and oil content.
Reproduction
Sexual reproduction
The Squash Cucurbita máxima, presents a system of sexual reproduction mediated perennially by entomophilic cross-pollination [2].
Asexual reproduction
Biologically no propagation or vegetative regeneration.
Growth
Phenologically it presents a short cycle system, registering an accelerated vegetative growth in the first 30 days, starting from this period the emission of the reproductive structures, and finishing the filling of the fruits between 3 and 4 months after the germination, this active development that shows Cucurbita máxima, is favored by having motor structures like the tendrils, which allow it to make certain movements in search of light photons [5].
Ecology
Cucurbita maxima, can develop in tropical, subtropical and temperate climates, however, their vegetative and reproductive structures show their maximum potential, at temperatures ranging from 18 to 25 °C, relative humidity around 70%, preferably acidic soils rich in organic matter.
Histology and organography
Microscopic study
In order to extend the existing information, a histological study was developed on the vegetative structures of Cucurbita maxima, using the optical microscope for the morphological characterization at the level of tissues, the same was executed in the laboratory of Botany of the UNESUR - Venezuela.
Collection
The vegetative material of Cucurbita maxima, was collected from the short cycle cultivation area of UNESUR, a university institution located in Santa Bárbara, municipality of Colón in the state of Zulia - Venezuela.
Histological identification
The vegetative structures of Cucurbita maxima, were placed in containers with water to guarantee the maintenance of the turgidity of the tissues, later they were transferred to the laboratory facilities of Botany of the UNESUR.
Materials and reagents used
- Plants of Cucurbita maxima
- Carrier sheets and coverslips
- Botanical dissection team
- Petri dishes
- Optical microscope
- Distilled water
- Lugol
- Safranin
- Floroglucin
Tissue observation
The histological structures of Cucurbita maxima, were observed using OPTIKA brand microscopes, for the identification of epidermal tissue, photosynthetic mesophilic, transverse, longitudinal and tangential cuts were made to the leaves (both sides), first proceeded to focus at 4x to locate tissues and then changed to 10x, for morphological characterization.
For the observation of xylem conduction and phloem tissues, cross sections were made to young petioles and stems of Cucurbita máxima.
Histological results
Epidermal characterization
The adaxial and abaxial epidermis of Cucurbita maxima, has cells with rounded to irregular and pyliferous morphology, with pluricellular trichomes protruding from the leaf lamina.
Stomatic characterization and epidermal excrescences
The observed stomas are located in Amphistomatic disposition, this indicates that they are located on both sides of the leaf blades of Cucurbita maxima. In relation to the type of stoma observed, it was found to be anomocytic, in relation to the epidermal excrescences, unisex pluricellular trichomes were found in the form of hairs with a visible structural plane (base, body and head).
Parenchymal characterization
The foliar laminae of Cucurbita maxima, exhibit mesophyll with palatal and spongy parenchymal cells of irregular morphology, followed by colenchymal cells with appreciable angular thickening.
Xylematic and phloematic characterization
Histological sections made to young petioles and stem of Cucurbita maxima, showed excretions in the form of pluricellular trichomes, followed by epidermis, rounded parenchymal and cholenchymal cells with angular thickening, with vascular bundles of bicolateral aspect arranged in rings.
SCIENTIFIC CONTRIBUTIONS OF THIS PUBLICATION
- It is relevant to indicate, that the organographic, morpho-anatomical, histological description of the plant species Cucurbita maxima, supported with food information, includes unpublished contributions within the HIVE social network, when referring to the content of plant morphology and utilitarian botany of the Squash as a resource of agricultural and food interest, On the other hand, the socialization of each scientific and technical topic treated in the post, provides in a referential way, taxonomic details of recognition for future morphological and histological descriptions, such as the phytomechanical capacity of the helical tendrils of C. maxima.
BIBLIOGRAPHICAL REFERENCES CONSULTED AND CITED:
[1] Jeffrey C. A review of the Cucurbitaceae. Botanical J. Linnean Soc. 1980; 81: 233-234. Article: Online access
[2] Díez M., and Nuez F. Cucurbit Genetic Resources in Europe. Ad hoc meeting. 2002; 19. Article: Online access
[3] Schaefer H., and Renner S. Cucurbitaceae. Flowering Plants. Eudicots: Sapindales, Cucurbitales, Myrtaceae. 2010; 112 - 174. Article: Online access</div
[4] FAO. Food and Agriculture Organization of the United Nations. Proyecto de revisión de la clasificación de alimentos y piensos: Grupos de hortalizas seleccionadas grupo 011: hortalizas de fruto, Cucurbitáceas. 2016. Article: Online access</div
[5] Rodríguez R., Valdés R., Ortiz G. Características agronómicas y calidad nutricional de los frutos y semillas de zapallo Cucurbita sp. Rev Colombiana Cienc Anim. 2018; 10; 1: 86 - 97. Article: Online access</div
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