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A facility that stores seeds in order to preserve genetic diversity for the future is referred to as a Seed Bank. These banks house vaults often made up of bombs, floods, and radiation-proof materials. Contained in these vaults are jars of seeds from various plant species all over the world. The seeds are typically stored at low humidity and cold temperatures (around -20°C), preserve the seeds and ensuring that they can grow again for future uses.

There are over 1,000 seed banks around the world, varying in type, size, and focus. The Millennium Seed Bank in Sussex, managed and coordinated by the Royal Botanic Gardens, is the world's largest seed bank that opened in 2000. It houses seeds from nearly 40,000 different species from all over the world, including nearly all of the native trees and plants the United Kingdom.

Depending on the species, seeds stored in these vaults could be dormant for hundreds or even thousands of years. However, because nothing like this has been attempted before, these predictions can only be based on models. There have been a few reports and examples of ancient seeds germinating in pyramids and ancient palaces, but data on seed longevity is limited. We can only rely on models until the first stored seeds reach 1,000 years old. The best prediction is that seeds will survive in vaults for at least 150 years – ideally much longer.

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Figure 1. Seed storages in the Millennium Seed Bank. Adapted from kew.org.

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Currently, estimated 40% of plant species across the world are on the verge of extinction. A seed bank is a form of insurance, allowing us to save as many plant species as possible from this fate, conserving the world’s plant genetic diversity. Movements in preserving the plant genetic diversity is much more important than ever before. Plants are under threat from many factors, including:
(1) climate change
(2) habitat loss
(3) pollution
(4) pests and diseases.

The rate at which they are having an impact is also increasing, posing an ever-increasing risk of an incremental and catastrophic loss. We may be losing plants at a faster rate than we are discovering them. Moreover, seed banks act as repositories for agriculturally important crops and plants.

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In the Philippines, agriculture and food account for nearly 15-20% of gross national income. It employs approximately 32% of the working population, and agricultural and food trade accounts for up to 10% of national exports. Rice, coconut, banana, maize, and cassava are the food crops that dominate agricultural production.

Amidst being an agricultural country, no seed bank has yet been established in the Philippines. Efforts in preserving the genetic diversity of the agricultural and endemic plants in the country are centered on the deposition of unique samples in the Svalbard Global Seed Vault. Unique samples in Svalbard, amounting to 13,271, have originated from the Philippines.

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LAND AREA: 3,662 sq.km.
BORDERS: Ilocos Sur (south), Abra (southeast), Cagayan (east), and South China Sea (west).
CITIES: 2 ( Laoag & Batac)
TOWNS: 21 (Adams, Bacarra, Badoc, Bangui, Banna, Burgos, Carasi, Currimao, Dingras, Dumalneg, Marcos, Nueva Era, Pagudpud, Paoay, Pasuquin, Piddig, Pinili, San Nicolas, Sarrat, Solsona & Vintar)
PROXIMITY: By air: 45 minutes from Manila; 55 minutes from Kaoshiung; 80 minutes from Guangzhou, Hongkong & Taipei; and 2.15 hours from Shanghai. By land: 8 hours from Manila; 4 hours from Baguio
SEASONS: Dry (November to April) and wet (May to October)
CLIMATE: Average temperature is 26.8C
LANGUAGE: Iloko (Ilocano) is the common language, although English and Filipino are widely used.
BIODIVERSITY: The Biodiversity of Ilocos Norte Plant Species Ilocos Norte is well known for its many ornamental, medicinal, and edible plants. These plants beautify our homes, cure common diseases, and provide nourishment in a variety of ways because they can be cooked in a variety of ways.

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Figure 2. Map of Ilocos Norte, Philippines. Adapted from Birhane et al. (2016).

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The province of Ilocos Norte boasts immense biodiversity. Unfortunately, like any other area in the Philippine archipelago, it is vulnerable and fragile due to its constant immersion in pressure from excessive human exploitation and numerous infrastructure developments, aggravated by the drastic changes in the climatic condition. In 2001, genetic conservationists from Mariano Marcos State University in the City of Batac, Ilocos Norte, reported more than 100 native plant species in the province as endangered (Read more: https://www.philstar.com/business/agriculture/2001/11/25/141330/more-100-plant-species-ilocos-norte-deemed-endangered). This report has urged the scientists in the province to collect plant material samples, averting genetic erosion and further loss of biodiversity.

Several researchers from the country have investigated, as well, the biodiversity in the Metropolitan Ilocos Norte Watershed Forest Reserve (MINWFR), one of the critical ecosystems in the province. Shown in Figure 3 is the summary of the plant families and species recorded MINFWR, Northwestern Luzon, Philippines (Batuyong et al., 2020).

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More than a hundred plant species are now considered endangered in Ilocos Norte, but genetic conservationists in the Mariano Marcos State University (MMSU) have started to collect planting materials from the few remaining plants to avert genetic erosion and loss of biodiversity.

Dr. Miriam E. Pascua, dean of the MMSU College of Agriculture, and her five co-workers claim that these plant species are fast disappearing and are likely to become extinct unless something is done to reverse the situation. They assert that the following scenarios have led these plant species to near extinction:

* Newly developed modern and high yielding crop varieties have spread across many places and are replacing native varieties with unique characteristics.

* The loss of genetic biodiversity could be due to the intensification of the agricultural system, over exploitation and excessive gathering of wild plants that are useful for food, medicine and ornamentals, inadvertent introduction of insect pests and diseases, and establishment of commercial plantation of industrial crops.

* Increasing population pressure and the resulting urbanization of the environment have greatly increased the demand for raw materials to meet basic necessities and support emerging industries.

Elderly folks asked to identify plants that are hardly seen nowadays asserted that some of the vanishing species have superior characteristics, such as good eating quality, low input requirement, adaptability to different ecological niches, and resistance to pests and other biotic and abiotic stresses.

Thus, these species could be tapped in the development of new cultivars, strains and hybrids, as well as in restructuring varieties that lack some attributes.

These species could also be tapped for the production of natural products, such as medicines and health foods in response to the growing health consciousness of people.

Considered vanishing among the vegetables are the following: Balinsoek, red cowpea, cayenne pepper, kundol, kapas-kapas, sugod-sugod, himbabao and wild sponge gourd.

The legumes balinsoek and red cowpea are resistant to weevil and have good eating quality. Unlike most legumes, the seeds of balinsoek are hardly infested by weevil. On the other hand, cayenne pepper, a wild Capsicum species, is a favorite spice, especially when soaked in vinegar (inartem). A strong infusion of the fruits can be applied as a lotion for ringworm control, while a warm liquid extract of both the leaves and fruits can be applied as an ointment to relieve rheumatic pain.

Kundol, kapas-kapas, sugod-sugod, himbabao and wild sponge gourd are eaten as vegetable. However, they have other uses. For instance, sugod-sugod was used as laundry soap during the second World War. When dried and crushed, its vine produces a lathery effect when soaked in water.

Among fruit and forest trees, the following are considered vanishing: dalayap (Citrus aurantifolia), caburao (Citrus macroptera), darukis (Citrus sp.), custard apple or anonang (Anona reticulata), mansanitas (Zyzyphus mauritiana), antipolo (Artocarpus blanco), balayang (Musa errans), pomegranate (Punica granatum), bignay (antidesma bunius), carissa (Carissa carandas), zapote Negro (Diospyrus ebenaster), and pannalayapen or aping.

The tops of pannalayapen, a woody forest Plant, are consumed as green leafy vegetable.

Most of the vanishing fruit and forest trees have medicinal uses. For example, dalayap and caburao are commonly used for treating cough and headache. Their leaves are crushed Or softened and then applied as poultice over the forehead to treat headache.

On the other hand, fresh leaves of anonang are applied on the stomach of children who are suffering from indigestion. Likewise, a decoction of its green fruits, leaves and barks is used for treating kidney trouble, dysentery and diarrhea.

Pomegranate fruits are also used for treating diarrhea, advanced stages of dysentery, and other cases requiring the use of astringents. The juice of the fresh fruit is likewise used as a cooling, thirst-quenching beverage for one who has fever. (To be continued)

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More than 100 plant species in Ilocos Norte deemed endangered

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More than a hundred plant species are now considered endangered in Ilocos Norte, but genetic conservationists in the Mariano Marcos State University (MMSU) have started to collect planting materials from the few remaining plants to avert genetic erosion and loss of biodiversity.

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Figure 3. Representation of vascular families and species recorded in MINFWR, Northwestern Luzon, Philippines. Adapted from Batuyong et al. (2020).

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Scientific Name: Diospyrus montana var. timorensis Bakh.
Common Names: Bombay Ebony (English), Ballatinaw (Ilocano)
Habit: Tree
Conservation Status: Not evaluated (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Endemic
Description: Various parts of the plant have been reported to be used in fever, dysuria, gravel, neuralgia, pleurisy, pneumonia, menorrhagia and flooding, puerperal fever, diarrhea, and poisonous spider bite. Bark extract has anti-inflammatory, antipyretic, and analgesic properties. Aside from its potential medicinal purposes, seeds of this plant must be preserved since it is endemic in the province.

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THE BOMBAY EBONY/BALLATINAW PLANT AND ITS FRUITS

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Scientific Name: Shorea contorta S.Vidal
Common Name: White Lauan (English)
Habit: Tree
Conservation Status: Least Concern (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Endemic
Description: The wood of White Lauan is used in the general construction of furniture and cabinets, boat planking, mining timbers, and papermaking. It is also used in the production of boxes, crates, utensils, and veneer plywood. Apart from its industrial uses, this plant species is endemic to the province. That said, its genetic features must be preserved.

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THE WHITE LAUAN PLANT

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Scientific Name: Podocarpus polystachyus R.Br. ex Endl.
Common Names: Sea Teak (English); Igem (Ilocano)
Habit: Tree
Conservation Status: Vulnerable (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Native
Description: The wood of Igem is used for interior work, beams, framing, furniture, and oars as a light to medium-weight softwood timber. Unfortunately, this plant species is vulnerable or at verge of extinction; hence, preservation of seeds must be also conducted, averting genetic erosion.

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THE SEA TEAK / IGEM TREE

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Podocarpus polystachyus - National Parks Board

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Scientific Name: Radermachera coriacea Merr.
Common Name: Radermachera coriacea
Habit: Tree
Conservation Status: Vulnerable (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Endemic
Description: Radermachera coriacea is valued for its decorative features. Although it has no known medicinal and industrial importance, it has a conservation status of vulnerable. As it is an endemic plant in the area, its conservation must be highlighted.

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THE RADERMACHERA CORIACEA FLOWER

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Scientific Name: Diospyros pilosanthera Blanco
Common Name: Bolong-eta (Ilocano)
Habit: Tree
Conservation Status: Vulnerable (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Native
Description: Furniture is made from the wood of Bolong-eta. The wood is used for fancy woodwork, furniture, cabinet making, and tool handles as streaked ebony. It is occasionally used for piling. Apart from its industrial importance, the seeds of Bolong-eta must be subjected to preservation since it is at the verge of extinction.

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THE BOLONG-ETA TREE

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Scientific Name: Colocasia esculenta (L.) Schott.
Common Names: Aba (Ilocano)
Habit: Herb
Conservation Status: Least Concern (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Native
Description: Since ancient times, the herb has been known for its curative properties and has been used to treat a variety of ailments including asthma, arthritis, diarrhea, internal hemorrhage, neurological disorders, and skin disorders. Furthermore, Aba is also a delicacy in the province. As a source food that can feel a large human population, seeds of the must be highlighted for preservation.

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THE ABA HERB

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colocasia esculenta - north carolina extension gardener plant toolbox

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Scientific Name: Dracontomelon dao (Blanco) Merr. & Rolfe
Common Names: Argus Pheasant Tree (English)
Habit: Tree
Conservation Status: Vulnerable (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Native
Description: The tree is harvested in the wild for local consumption as food, medicine, and a source of wood. The fruit is occasionally available in local markets and is a popular food in some areas. In villages, the tree is planted as a fruit tree as well as an ornamental in roadside plantings. Unfortunately, this plant species has been classified as vulnerable or at the verge of extinction.

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THE ARGUS PHEASANT TREE

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Scientific Name: Artocarpus blancoi (Elmer) Merr.
Common Names: Antipolo (Tagalog; Ilocano)
Habit: Tree
Conservation Status: Vulnerable (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Endemic
Description: The wood is used as terap in local construction. Perhaps more importantly, it is used as a fiber plant in the production of pulp and paper. The bast is made into weak ropes, which have been used to yoke buffaloes, for example. An extract of the bark has potent antimicrobial properties. Unfortunately, due to excessive human exploitation, antipolo is at the verge of extinction; hence, preservation of its genetic features must be performed.

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THE ANTIPOLO TREE

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Scientific Name: Pterospermum obliquum Blanco
Common Names: Bayok-bayok (Ilocano)
Habit: Tree
Conservation Status: Least Concern (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Endemic
Description: The bark is used locally to dye brownish fishermen's cloth. The bark can also be used to make tannin. The wood is used in house construction for interior work as well as furniture, cabinetry, and implements. Due to its endemicity, its genetic perseveration must be highlighted.

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THE BAYOK-BAYOK FLOWER

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Scientific Name: Areca ipot Becc.
Common Names: Betel Nut (English); Bua (Ilocano)
Habit: Tree
Conservation Status: Vulnerable (DENR Administrative Order 2017-11 and IUCN Red List)
Endemicity: Endemic
Description: Its native habitat is threatened by habitat destruction and over-collection of seeds for betel nut chewing. It is best suited to cultivation in the tropics. It grows quickly and easily and has a lot of potential as a landscape plant.

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THE BETEL NUT/ BUA TREE

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Figure 14. Anatomical structures of various seeds from different plant groups, which changes are associated with the plant's evolution.  Common to all seeds are the seed coat (testa), but in some cases, it is fused to the pericarp. The seeds can be broadly categorized as either endospermic, which relies on endosperm for stored reserves, or non-endospermic, which relies on their large storage cotyledons for food reserves.

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(1) Zygotic stage – first stage of diploid life.
◎ Polarized growth of the cell, proceeded by asymmetric transverse division, giving rise to an elongated basal cell and a small apical cell.

(2) Globular stage – apical cell undergoes series of division, creating an eight-cell (octant) globular embryo that exhibits radial symmetry
◎ Additional cell division occurs producing the outer layer proctoderm (fate: epidermis)

(3) Heart stage – focused cell division on either side of the potential shoot apical meristem, forming the two cotyledons.
◎ Gives the embryo bilateral symmetry.

(4) Torpedo stage – cell elongation and cellular differentiation processes ensue all over the embryonic axis
◎ Distinctions between the adaxial and abaxial tissues become obvious.

(5) Mature stage – toward the end of embryogenesis.
◎ Three processes occur during the maturation stage:

Store food - Storage compounds accumulate in the cells.

Desiccation - Loses water

Enter dormancy – promoted by the abscisic acid hormone.

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Figure 15. Arabidopsis embryogenesis is characterized by a precise pattern of cell division. Successive stages of embryogenesis are depicted here. (A) One-cell embryo after the first division of the zygote, which forms the apical and basal cells; (B) two-cell embryo; (C) eight-cell embryo; (D) early globular stage, which has developed a distinct protoderm (surface layer); (E) early heart stage; (F) late heart stage; (G) torpedo stage; (H) mature embryo.

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(1) Zygotic stage – single cell stage, produced from the fusion of egg and sperm haploid cells
(2) Globular stage – Formed from horizontal division, producing apical and basal cells. Sequential divisions create a multilayered globular embryo.
(3) Coleoptile stage – Occurs 5 days after pollination, where radicle, root apical meristem, coleoptile, and shoot apical meristem forms.
(4) Juvenile vegetative stage – the shoot apical meristem produces several vegetative leaves
(5) Maturation stage – maturation-related genes are expressed preceding the onset of dormancy

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Figure 16. Rice embryonic development illustrating the globular stage (A), coleoptile stage (B), juvenile embryo stage (C), and mature embryo stage (D). The scutellum is a modified cotyledon specialized to absorb sugars released from the endosperm during germination.

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Figure 17. In longitudinal cross section (left), the apical-basal axis extends between the tips of the embryonic root and shoot. In transverse cross section (right), the radial axis extends from the center to the surface across vascular, ground and epidermal tissues.

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Common to all seed plants is the polarity, which is referred as the polarization of plants along two axes, (1) the apical-basal axis and the (radial axis).

Intercellular signaling processes are vital in the plant polarization, for they function in the position-dependent development of plants. The presence specific cues are responsible for the unique positions of a developing structures. Cells contain mechanisms that respond to these cues, assessing their location in relation to these signals.

This polarization is promoted by various hormones and genes. The hormone auxin is essential in embryogenesis. They act as a mobile chemical signal that can induce embryo formation from somatic cells and can stimulate concentration-dependent responses in different tissues. The plant’s polarity is regulated by the polar auxin streams. Two transport, rootward and shoot ward transport, of auxin are the main mechanisms responsible for the plant’s programmed directional growth. Cytokinin is another hormone that is needed for the root development, wherein it is proven that crosstalk between auxin and cytokinin occurs during embryogenesis. High levels of auxin promotes root formation, while high levels of cytokinin promotes shoot formation. Auxin is synthesized in shoots and is transported rootward, while cytokinin is produced in the roots and is transported shootward.

The genes associated with this polarization are the gurke, fackel, gnom, and monopteros. Gurke encodes for the acetyl-CoA carboxylase that is required in synthesizing long-chains of fatty acids and spingolipids. They are critical for the patterning of the apical portion of the embryo. Fackel encodes sterol C-14 reductase, which is important for the pattern formation occurring during embryogenesis. They are needed for the formation of hypocotyl. Gnom encodes for guanin nucleotide exchange factor that enables directional transport of auxin. Lastly, monopteros encodes for the auxin response transcription factor, which regulate specific genes that is involved in auxin responses. Monopteros is required for the formation of central and basal domain of the embryo.

The radial axis runs perpendicular to apical-basal axis. This patterning serves as the guide in the tissue layers formation. Proctoderm is a one-cell thick outermost layer that will later become the epidermis. Ground tissue lies below the proctoderm and will soon differentiate into cortex, and endodermis in the root and hypocotyl. The procambium is the innermost/ central domain that produces pericycle of the root and vascular tissues, needed in transporting water and nutrients.

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Figure 18. Summary of the sequence of radial patterning events during Arabidopsis embryogenesis. The five successive embryonic stages shown in the longitudinal section illustrate the origin of distinct tissues, beginning with the delineation of the protoderm (left) and ending with the formation of the vascular tissues (right). Note how the number of tissues increases through the action of stem cells. A cross-sectional view of the basal portion of the late heart stage embryo is shown at the far right (the level of the cross-section is shown by the line in the longitudinal section to its left)

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Seed dormancy is an intrinsic property that temporarily prevents seed germination to provide time for the seed dispersal to occur over a wide geographic distance or seasonal dormancy cycling, which is for seed bank. This prevents seed germination in unfavorable environmental conditions.

Seed dormancy and germination is regulated by the ration of two hormones: abscisic acid (ABA) and gibberellin (GA). The hormonal activity of the seed depends on the amount of each hormone present within specific tissues and its ability to respond to those hormones. ABA is known to be an inhibitory effect on seed germination, thus, promotes dormancy, while GA promotes germination.

Seed dormancy that is imposed on the embryo by its surrounding tissues (i.e., seed coat, endosperm, pericarp), is known as the coat-imposed dormancy (e.g., legumes and wild mustard). This kind of seeds readily germinates on the presence of oxygen and water when its surrounding tissue got damaged or removed. On the other hand, seed dormancy can be intrinsic to the embryo itself, which is referred as embryo dormancy (e.g., celery and carrot). Sometimes, this can be relieved by removing its cotyledons, while some cases, the embryo just needs time to fully mature.

Dormancy can be relieved through alteration of the metabolic state of the seed. Some seeds are photoblasty (e.g. Lettuce) that requires exposure to light for a specific period and interval. Some seeds (e.g. Barley) need after-ripening to break dormancy. The duration of after-ripening depends per plant species. Furthermore, there are seeds (e.g., Bluntseed sweetroot) that require chilling to break dormancy. Stratification can break such seeds, which involves overwintering in layered soil or sand. This can also be done by simply storing moist seeds in the refrigerator. Moreover, there are various chemical compounds that can be used to break dormancy, such as oxidants and sulfhydryl compounds; however, only few occurs naturally. Hedge mustard requires nitrate and light to break dormancy, other seeds need nitric oxide, while some requires smoke.

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Germination is a process that requires various factors, such as water, light, nitrate, temperature, and oxygen. This is divided into three phases. Phase I is where the dry seeds take in water via imbibition. Matric potential plays an important role in this process. Matric potential creates a gradient by lowering the water potential in the dry seed. This emerges from the interaction that occurs between water molecules and the solid surfaces of various macromolecules in the seeds. This rehydrates these cellular components, activating the basal metabolic processes. Imbibition stops when the potential binding sites for water become saturated. Phase II involves the reduction of the uptake of water until the water potential gradient is restored. Metabolic processes are reinitiated, the embryo expands, and the radicle arises from the seed coat. Phase III occurs when the water uptake resumes due to the cell expansion, which involves loosening of cell wall. During this phase, the water potential is maintained by the solute accumulation and relaxation of cell wall. In this phase the food storage is fully mobilized.

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Figure 19. Phases of seed imbibition. In Phase I, dry seeds imbibe water rapidly. Since water flows from the higher to the lower water potential, the water uptake by the seed stops when the difference in water potential between the seed and the environment becomes zero. During Phase II the cells expand and the radicle emerges from the seed. Metabolic activity increases and cell wall loosening occurs. In Phase III, water uptake resumes as the seedling becomes established.

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Food reserves of the seeds are usually located at the endosperm or in the cotyledons. The mobilization of these stored reserves happens after germination, where nutrients are already provided, and the seedlings become autotrophic. Starches are stored in amyloplast and mobilizing this requires starch degradation. The enzymes a- and B-amylase are responsible for this degradation. The a-amylase hydrolyzes starch chains to produce oligosaccharides, which are further degraded by the B-amylase, producing maltose. Maltose is then converted to glucose to be utilized by the seedlings. A specialized digestive tissue known as the aleurone layer surrounds the endosperm. This generates and releases enzymes that hydrolyzes these reserves. The products produced are then transported to the growing embryo via scutellum.

Additionally, protein storage vacuoles provide the amino acids needed for the seedling’s protein synthesis. During mobilization of stored reserves, the phytase enzyme hydrolyzes phytin, releasing phosphate and various ions to be used by the seedling.

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Figure 20. Structure of barley grain and the functions of various tissues during germination. (A) Diagram of germination-initiated interactions. (B–D) Micrographs of the barley aleurone layer (B) and barley aleurone protoplasts at an early (C) and a late (D) stage of amylase production. Multiple protein storage vesicles (PSVs) in (C) coalesce to form a large vesicle in (D), which will provide amino acids for α-amylase synthesis. G, phytin globoid that sequesters minerals; N, nucleus.

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Plants does not grow randomly, but rather responds to various stimuli that guides its directional growth. Tropism can either be positive, which grows in the direction of the stimulus, or negative that grows on the opposite direction of the stimulus. There are different types of tropism, these are: Gravitropism, Phototropism, and Thigmotropism. Gravitropism refers to the directional growth in response to gravity. Examples of positive gravitropism are the roots, while the shoots are examples of negative gravitropism. On the other hand, plants that are phototropic responds to sunlight, which is essential in maximizing photosynthesis. Thigmotropism refers to the growth in response to touch. A great example of this is the plant Mimosa pudica, commonly known as the Makahiya.

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Figure 21. Examples of different tropism and how they react to different stimuli.

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