Edible Durio of Sarawak

There are 31 known species of Durio.   12 species have been identified to produce edible fruits.   7 out of 12 edible species can be found in various places of Sarawak.

No	Edible Species	Distribution
1	Durio dulcis	Borneo
2	Durio grandiflorus	Borneo
3	Durio graveolens	Borneo, Malaya, Palawan, Sumatra
4	Durio kinabaluensis	Crocker Range
5	Durio kutejensis	Borneo
6	Durio lowianus	Malaya, Sumatra
7	Durio macrantha	Sumatra
8	Durio mansoni	Indochina
9	Durio oxleyanus	Borneo, Malaya, Sumatra
10	Durio testudinarius	Borneo
11	Durio wyatt-smithii	Terengganu
12	Durio zibethinus	Borneo, Sumatra

No	Other Species	Distribution
1	Durio acutifolius	Sabah, Kalimantan
2	Durio affinis	Kalimantan
3	Durio beccarianus	Borneo
4	Durio bukittrayaensis	borneo
5	Durio burmanicus	Borneo
6	Durio carinatus	Borneo, Malaya,  Sumatra
7	Durio  ceylanicus	Sri Langka
8	Durio crassipes	Tenom, Sipitang
98	Durio exceisus	Kalimantan
10	Durio griffithii	Borneo, Malaya, Sumatra
11	Durio lanceolatus	Borneo, Sumatra
12	Durio lissocarpus	Borneo
13	Durio macrolepis	Malaya
14	Durio macrophyllus	Malaya
15	Durio malaccensis	Malaya, Sumatra
16	Durio oblongus	Sarawak
17	Durio penangianus	Perak, Penang
18	Durio purpureus	Kalimantan
19	Durio singaporensis	Malaya

Roller-Tanker

Roller-Tanker® is an innovation of local company S Two Green Landscape. 

It is an upgraded version or roller-bins, which are used in solid waste disposal. 

The tanker is custom made to fit to the truck, with dimension of the tank approximate 2.5m width x 4.5m length x 1.5m height.  Additional 1.5m compartment at rear for water pump.

The biggest advantage of Roller-Tanker® is that it can be detached from the truck for watering, while the truck can go about doing other tasks, or go for reload of water with a second Roller-Tanker®. 

Phytohormones 2

Plant hormones control all aspects of growth and development :-

embryogenesis,

regulation of organ size,

pathogen defense,

 stress tolerance,

reproductive development.

The term 'phytohormone' was coined by Went and Thimann, in their book ”Phytohormone” in 1937.

Chemical compounds synthesized by humans which are used to regulate the growth of cultivated plants, weeds, and in vitro-grown plants and plant cells; are called plant growth regulators ( PGRs ).

Initial research into plant hormones identified five major classes: abscisic acid, auxin, cytokinins, ethylene and gibberellins.  The list was later expanded to include brassinosteroids, jasmonates, salicylic acid and strigolactones.

Brassinosteroids

Brassinolide, a major brassinosteroid Brassinosteroids are a class of polyhydroxysteroids, the only example of steroid based hormones in plants. Brassinosteroids control cell elongation and division, gravitropism, resistance to stress, and xylem differentiation. They inhibit root growth and leaf abscission.

Brassinolide was the first identified brassinosteroid and was isolated from extracts of rapeseed (Brassica napus) pollen in 1979.

Jasmonates ( JAs )

Jasmonates are lipid-based hormones that were originally isolated from jasmine oil. JAs are especially important in the plant response to attack from herbivores and necrotrophic pathogens.

The most active JA in plants is jasmonic acid. Jasmonic acid can be further metabolized into methyl-JA, which is a volatile organic compound. This unusual property means that methyl-JA can act as an airborne signal to communicate herbivore attack to other distant leaves within one plant and even as a signal to neighboring plants.  In addition to their role in defense, JAs are also believed to play roles in seed germination, the storage of protein in seeds and root growth.

Salicylic Acid ( SA )

Salicylic acid is a hormone with a related structure to phenol. It was originally isolated from an extract of white willow bark (Salix alba) and is of great interest to human medicine, as it is the precursor of the painkiller, aspirin.

In plants, SA plays a critical role in the defense against biotrophic pathogens. In a similar manner to JA, SA can also become methylated. Like methyl-JA, methyl-SA is volatile and can act as a long distance signal to neighboring plants to warn of pathogen attack. In addition to its role in defense, SA is also involved in the response of plants to abiotic stress (particularly drought, temperature, heavy metal and osmotic stress).

Strigolactones ( SLs )

Strigolactones are originally discovered through studies into the germination of the parasitic weed Striga lutea. It was found that the germination of Striga species was stimulated by the presence of a compound exuded by the roots of its host plant.   It was later shown that SLs that are exuded into the soil promote the growth of symbiotic arbuscular mycorrhizal (AM) fungi.  More recently, another role of SLs was identified in the inhibition of shoot branching.  This discovery of the role of SLs in shoot branching led to a dramatic increase in the interest in these hormones, and it has since been shown that SLs play important roles in leaf senescence, phosphate starvation response, salt tolerance and light signalling.

Phytohormones

• E. Starling coined the term “hormone” in connection with the discovery of Secretin.

• Hormones are organic compounds secreted in small quantities that regulate the plant’s activities after being translocated to the organ or site of reaction where they show their specific effect.

• Five major kinds of plant hormones are :

Auxins

Cytokinins

Gibberellins

Ethylene

Abscisic acid

Auxins

• 1898 - proposed by Charles Darwin in “The power of movements in plants” while working on Canary grass (Phalaris cannariensis).

• 1928 - W. Went discovered auxins by Avena curvature test.

• 1931 - Kogl and Haagen Smit isolated Auxin-A (Auxintriolic acid)

• 1934 - Kogl and Haagen Smit isolated Auxin-B (Auxinolonic acid)

• 1935 – isolated heteroauxins.

Natural auxin : Indole-3-acetic acid (IAA)

Synthetic auxins : Nephthalene acid (NAA), indole butyric acid (IBA), indole propionic acid (IPA), 2,4-Dichlorophenoxyacetic acid (2,4-D), 2,4,5-Trichlorobenzoic acid (2,4,5-T) etc.

Funtions of Auxins

• Elongation of the cell.

• Apical dominance

• Root initiation (IAA, NAA, IBA, IPA )

• Herbicides ( 2,4-D, 2,4,5-T)

• inhibit sprouting of potato

• induce flowering (NAA,  2,4-D)

• abscission of fruits.

• stimulate cell wall synthesis and parthenocarpy.

Cytokinins ( Kinetins )

• 1940s - extracted from coconut milk.

Adenine-type cytokinis : kinetin, zeatin, 6-benzylaminopurine (BA )

Phenylurea-type cytokinis : diphenylurea, thidiazuron (TDZ)

Functions of Cytokinins

• Activates cell division.

• Acts in concert with Auxins :  Formation of callus , cell elongation in roots, embryos & fruit

• Acts in reverse with Auxins :  promote axillary bud, inhibits branch roots

• Prevents ageing and senescence in plants.

Gibberellins

•1926 -  isolated from a fungus Gibberella fugikuroi in the “bakanae disease”infected rice plant.

• > 100 naturally occurring gibberellins

Functions of Gibberellins

• induces seed germination

• stimulate stem elongation and leaf expansion.

• break dormancy in potato tubers and tree buds in winter.

• Induces flowering in LD plants

• causes parthenocarpy in pome fruits

• increases the number of male flowers  in moneecious plants

Ethylene

• gaseous hormone.

• synthesized from methionine.

• released from roots, shoot meristems and ripening fruits.

Functions of Ethtylene:

• induces ripening of fruits.

• accelerates abscission of leaves, stems, flowers and fruits.

• induces flowering in pineapple.

• Induces epinasty in leaves.

Abscisic acid (ABA)

•  produced in mature leaves, stem, fruits and seeds.

Functions of Abscisic acid

• accelerates abscission.

• inhibits seed germination

• also accelerates senescence in leaves.

• causes the closing of stomata

• Inhibits fruit ripening 

The Flora of Tasik Bera

Four main plant communities and habitats, (a) open water vegetation, (b) rassau swamp, (c) Lepironia reed-bed and (d) freshwater swamp, are found in Tasik Bera, which is surrounded by (e) lowland dipterocarp forest.

Open Water Vegetation 

Menyanthaceae	Nymphoides indica
Nymphaeaceae	Nymphaea nouchali
Hydrocharitaceae	Blyxa aubertii
Lentibulariaceae	Utricularia aurea Utricularia punctate Utricularia uliginosa
Characeae	Nitella sp.

Rassau Swamp 

Elaeocarpaceae	Elaeocarpus macrocerus Elaeocarpus griffithii
Myrtaceae	Syzygium cinereum
Flagellariaceae	Flagellaria indica
Nepenthaceae	Nepenthes gracilis
Araceae	Cryptocoryne purpurea
Pandanaceae	Pandanus helicopus

Lepironia Reed-bed 

Cyperaceae	Lepironia articulate Scirpus mucronatus Cyperus haspan Eleocharis ochrostachys Fimbristylis acuminate Fimbristylis griffithii Fimbristylis umbellaris  Mapania bancana
Onagraceae	Ludwigia adscendens Ludwigia hyssopifolia
Melastomaceae	Melastoma malabathricum
Gleicheniaceae	Dicranopteris linearis
Lygodiaceae	Lygodium microphylum
Rubiaceae	Hedyotis herbacea

Freshwater Swamp 

Myrtaceae	Syzygium spicatum
Dipterocarpaceae	Vatica lobata
Anarcardiaceae	Cryptocoryne purpurea
Euphorbiaceae	Ilex cymosa
Rhizophoraceae	Campnosperma auriculatum
Euphorbiaceae	Glochidion rubrum
Rhizophoraceae	Gynotroches axillaris
Rubiaceae	Gardenia tubifera var.tubifera Gardenia pterocalyx Uncaria cordata var. ferruginea
Rutaceae	Luvunga sarmentosa Merrillia caloxylon

Lowland Dipterocarp Forest 

Fabaceae	Koompassia malaccensis
Dipterocarpaceae	Anisoptera scaphula Dipterocarpus cornutus Dipterocarpus costulatus Dipterocarpus crinitus Dipterocarpus kerrii Hopea mangerawan Parashorea stellata Shorea curtisii ssp.curtisii, Shorea leprosula Shorea ovalis Shorea parvifolia Vatica pauciflora
Ctenolophonaceae	Ctenolophon parvifolius
Sapotaceae	Payena lucida
Burseraceae	Canarium littorale
Apocynaceae	Dyera costulata
Ixonanthaceae	Ixonanthes icosandra
Anacardiaceae	Gluta elegans
Euphorbiaceae	Endospermum diadenum Pimelodendron griffithianum Agrostistachys longifolia
Fagaceae	Lithocarpus wallichianus
Myrtaceae	Rhodamnia cinerea
Pandanaceae	Galearia fulva
Asteraceae	Licuala ferruginea Licuala longicalycata Licuala longipes
Zingiberaceae	Alpinia pahangensis
Aristolochiaceae	Thottea grandiflora
Lamiaceae	Clerodendron deflexum
Myrsinaceae	Ardisia crenata
Melastomaceae	Phyllagathis rotundifolia
Rubiaceae	Mussaenda mutabilis Mussaenda glabra Croton caudatus
Olaceae	Erythropalum scandens
Orchidaceae	Vanilla griffithii

Chew M.Y. et al, The Flora of Tasik Bera, Pahang, Malaysia, Malayan Nature Journal 2010, 62(3), 249-306