Sunday, 18 April 2021

Actinorhizal Plants

Actinorhizal plants are a group of angiosperms characterized by their ability to form a symbiosis with the nitrogen fixing actinobacteria Frankia. 

Actinorhizal plants are dicotyledons distributed among 3 orders, 8 families and 24 genera.  These three orders form a single clade within the Rosids, which is a sister taxon to the other major nitrogen-fixing order, the Fabales.  Not all plants in this clade are actinorhizal, however. 



Order

Family

Genus

Cucurbitales

Coriariaceae

Coriaria

Datiscaceae

Datisca

Fagales

Betulaceae

Alnus

Casuarinaceae

Allocasuarina
Casuarina
Ceuthostoma
Gymnostoma

Myricaceae

Comptonia
Myrica

Rosales

Elaegnaceae

Elaeagnus
Hipophae
Shepherdia

Rhamnaceae

Colletia
Discaria
Kentrothamnus
Retanilla
Talguenea
Trevoa
Ochetophila
Ceanothus

Rosaceae

Cercocarpus
Chamaebatia
Cowania
Dryas
Purshia

 

 

Actinorhizal plants are found on all continents except for Antarctica. Their ability to form nitrogen-fixing nodules confers a selective advantage in poor soils. Most actinorhizal plants are therefore pioneer species that colonize young soils where available nitrogen is scarce. 



Other nitrogen fixing families include Trema ( Parasponia ), a tropical genus in the family Cannabaceae, which are able to interact with Rhizobia.

 

 

 

Sunday, 13 September 2020

Saturday, 12 September 2020

路边的蔬菜摊 @ Covid-19 RMCO

进来徬晚时分,在Petronas 后面小路口有个印藉德士大叔排挡口买蔬菜。

下车看看问问。或许会遇到一些惊喜。











惊?喜?







Wednesday, 26 August 2020

Endemic Flora of Gunung Mulu National Park

Gunung Mulu National Park contains a large number of plant species. The park has 17 vegetation zones, with 3,500 species of vascular plants, and 1,500 species of flowering plants, 1,700 species of liverworts and mosses, 4,000 of fungi.  There are 109 species in 20 genera of palms, over 1,700 mosses and liverworts, 8,000 species of fungi, and 442 species of spore-producing pteridophytes, 182 species of orchid, 15 species of carnivorous pitcher plants are recorded.

Mulu’s limestone karst and isolated mountain peaks are home to numerous rare and endemic plants and animals. Notable examples of plants include the one-leaf plant Monophyllaea pendula, which can be seen clinging to the rock face at the entrance to Clearwater Cave; Salacca rupicola, an endemic palm that grows on the cliff outside Deer Cave; wild sago palm Eugeissona utilis, occurring on the steep slopes of Gunung Mulu; Areca abdulrahmanii, which grows on the Setap shales; and the pitcher plant, Nepenthes muluensis, which can be seen near the top of Gunung Mulu.  Iguanura melinauensis and Licuala lanata are endemic to the alluvial plain; Calamus neilsonii are endemic to the limestone.  Endemic mosses include Stereodontopsis flagellifera, Coryphopteria andersonii, Hypnodendron beccarii and Hypnodendron vitiense. The very rare bog-moss Sphagnum perichaetiale can be found in rain gullies in the high forest.












Tuesday, 25 August 2020

Rubber Tapping & Latex Processing


Tapping

The latex is extracting from rubber tree ( Hevea brasiliensis ) by skillfully slicing a groove into the bark of the tree with a specialty knife.  The trees must be approximately 6 years old and 150mm in diameter in order to be tapped.

The tapping work is done at night or in the early morning when the temperature is lower, so that the latex will drip longer before coagulating.

Ammonia solution are sometimes added to the collection cup to prevent natural coagulation and allow the latex to remain in liquid state.  Liquid latex is used to produce latex concentrate for manufacture of dipped goods or coagulated under clean and controlled conditions.  Natural rubber latex concentrate, is preserved with ammonia solution, contains 60% Dry Rubber Content ( DRC ).

  

Coagulating & Milling 


Latex is a suspension of isoprene, microscopic natural rubber particles in an aqueous medium.  These particles scatter light, making the latex solution appear white and homogeneous like milk.  The surfaces of the latex particles are charged, which creates forces of repulsion between them that keep them from coagulating. In the coagulation process formic acid neutralizes these charges, thereby eliminating the forces of repulsion between the particles. 


The coagulated latex block are then pressed to remove water by passage through rollers.  The last pairs of rollers are grooved and thus produce ribbed sheets.  The ribs increase the surface area and facilitates drying. 



The serum left after latex coagulation is rich in quebrachitol (QCT), and various water-soluble materials such as sugars, lipids, proteins and minerals, which can cause water pollution if the serum is directly discharged into the environment.  




Washing & Drying 

The freshly sheeted rubber are then soaked in running water for a short time after milling to wash off the residual non-rubbers and, to prevent discoloration and mold growth. 

Sheets were hung up to drip off the remaining water for 4 to 6 hours preferably in the shade to drain off the surface moisture and thereby reduce the smoking period. 

 

Smoking 



Dripped sheets which contain about 20% moisture are dried in a smoke house.   Smoking enables the sheets to absorb creosotic and other antiseptic substances which provide a preservative effect and anti-oxidant effect on to the rubber.  Temperature of the smoke house maintained at range between 48-54 °C. 

Generally, smoking could be completed within 4-5 days.

 

 


 

 

 

 

 

 

 

 

 

Wednesday, 12 August 2020