Suman Dahal

Mycorrhiza is a symbiotic association between certain fungi and the roots of higher plants .The plants which suffer nutrient scarcity ,especially P and N develops mycorrhiza. Basically there are 3 types of mycorrhiza 1.Ectomycarrhiza:           It is found among Gymnosperms and Angiosperms .In short roots of higer plants ,generally roots hair are absent .Therefore  the roots are infected by mycorrhizal fungi which ,in turn,replace the root hair (if present ) and form a mantle .The hyphae grow intercellularly and develop harting net  in cortex. 2.Endomycorrhiza:           The morphology of endomycarrhizal roots after infection and establishment ,remain unchanged .Roots hair develop into a normal way. They also penetrate the cortical cell and get established intracellularly by secreting extracellular enzyme .They are of two types ie I .A.M. fungi(Arbescular Mycorrhizal fungi)-penetrate and profusely branches . ii.VAM(Vessi...

Agents which inactivates the enzyme activities is known as inhibitors.In other word the chemical substances which reduced the velocity of particular enzyme is called inhibitors.Basically they are of two type reversible and irreversible. reversible are of 3 types ie 1.Competitive inhibitors:         The activity of enzyme is inhibit by blocking to active site by an inhibitors substances .The inhibitors resemble the substrate molecule in its molecular organization instead of enzyme substrate.It depend upon the concentration of substrate and inhibitors.For example Malonic acid(an inhibitors) competes with Succinic acid for the enzyme succinic acid dehydrogenase .This enzyme catalysed the oxidation of succinic acid in the process of cellular respiration.Both succinic acid and malonic acid resemble a lot in their structure. 2Non competitive inhibitors:            In non competitive inhibitors the inhibitors doesn't compete for the active...

Enzyme are biological catalysts which increase the rate of bichemical reactions. Factor affecting rate of reaction are as follow . 1.Enzyme concentration :        Enzyme molecules are larger than substrate molecules.In this system the substrate molecule are in relatively larger concentration as compared to the specific enzyme concentration ,the enzyme catalised reaction will be attened maximum speed .Further addition of substrate will have no effect on the reaction because all the active site of enzyme molecule have been saturated.Now,if the enzyme concentration increased and the substrate concentration is relatively higher in the system ,the rate of reaction will be increased .Again increase in the enzyme concentration will increase the rate of reaction ,but the time will be come when the rate will not increase due to the limiting effect of substrate concentration .Therefore enzymatic reaction is directly proportional to the concentration of  enzyme . 2.S...

Following steps are used for plant tissue culture 1.In vetro lab:        For in vitro culture a well equipped lab is require which must have a media room for nutrient medium preparation ,sterilization of glass,metal as well as others .Given facility are found on those lab are as follow . I.Nutrient medium preparation ,sterilization and storage of supplies ii.An artificial environment is require for the growth and development of culture plant . iii.Observation and evaluation of culture as hoped. Equipment for these culture       Refrigerator,hot air ovan,Autoclave,Normal temperature balance,Normal chemical balance ,Microscope,PH meter,hot plate,gas stove/heater ,hot plate with regulator ,magnetic stirrer,water dissolution plant. Apparatus required : Test tube(20cc-2000cc),Measuring cylinder (5-1000ml),pipette(0.01-10ml),petri dish(4-8inches ),conical flask(50-3000ml),volumetric flask for storing chemicals50-500ml). Others:   Pointed forc...

Biofertilizer:           Biofertilizer is a substances which contain living microorganisms which ,when applied to seed,plant surface or soil ,colonize the interior part of plant and promotes growth by increasing the supply of all nutrient for plantand  helps in increasing the quality and quantity of plant. Cynobacteria as biofertilizer Isolation of BGA:           Algaligation it was japanese farmer who develop the technique for mass cultivation of BGA to be used as biofertilizer in paddy fields .Venkataraman(1961) coined the term algalization to denote the process of application of blue green algal culture in the field as biofertilizer.He iniated algaligation technology in india and demonstrate the way how this technology can be transferred to farmers . Preparation of starter culture:     First of all 5kg of surface paddy soil and water  were dilluted and kept in the tube containing fogg media maintaining the ...

Minerals are naturally formed chemical compound having a definite chemical composition ,an ordered internal arrangement of atoms and characteristic crystal form and physical properties .The ore is occurring materials from which a mineral or minerals of economic value can be excracted a profits .A continues well defined mass of minerals of sufficient ore content to make extraction economically feasible. There are several process of minerals /ore deposits 1.Magmatic concentration :              Magma is a molten rock together with a suspanded minerals grain and dissolve gases tgat forms when temperature rise and melting occurs in mentle and crust.Magnatic ore deposit are characteristic by their close relationship with intermediate or deep seated,intrusive igneous rock.Actually,they themselves are igneous rock whose composition happen to be of particular value to man.They constituent either whole igneous mass or a part of it ,or form offset bodies .T...

Gravity survey      Gravity survaying measures  earth gravitational field caused by different in the density of the sub source rocks.Gravity method have been used most extensively in search of oil and gas.While such method are still being used widely in hydrocarbons exploration . Application of gravity survey 1.Hydrocarbon exploration 2.Regional geological studies 3.Isostatic compensation determination 4.Exploration for mass estimation of minerals deposit 5.Detection of sub surface cavities 6.Location of burried rock valley 7.Determination of glacier thickness 8.Tidal oscillations 9.Archaeophysics (micro gravi\) 10.Shape of earth (geodesy) 11.Mililitary espically for missile trajectories 13.Monitoring volcanoes Gravity anonaly       A geophysic area where the gravitational attraction is significantly higher or significantly lower than normal.  So, gravity survey measure the change of rock density by looking at changing in gravit...

Rhizobia ha the ability to fix free atmospheric nitrogen of soil in nodules.They enter in the root through the soft root hair or epidermis by damaging them.In the first stage of infection the bacteria grow very profusely (rapidly)in the tip of the root hair and form the long filament in the root called infection thread.This thread reaches the endodermis and pericycle through cortex.Cell of the cortex area goes on dividing  and  forms new nodules.This young nodules pushes the paranchyma and epidermis towards outside and form small swelling on the surface of root.The size pf root nodule vary according to the plant and their occurrence .It is not necessary all the bacteria ,which infect the root produce nodules. According to Wipf and Cooper(1939) the root nodules always contains twice the number of chromosome as against of normal somatic tissue.If the root lack double number of chromosome ,their will be no formation of root nodules.If plant do not have root nodule it cannot perf...

Weathering is the breakdown of rocks,soil and their minerals through direct contact the earth atmosphere ,water,and living things .Weathering refers to the disintregation and decomposition of rocks in contact with different medium .It is related to the condition at which weathering take place.in other word temperature ,pressure ,rainfall,vegetation covers,rock types,and slope condition are major factor to pormotes weathering . weathering occur in situ(in place ,with no movement )It is the type of erosion .Erosion in where rocks and minerals are moved downward but not in weathering.In nature is continuous struggle for existence as well as supremacy between external of land distruction and internal forces of land deposition.The configuration of earth undergoes regular changes .Rock disintregrate and decomposition and move lower  under gravity and are carried by many factor like running water,glacier,wind waves and tides.All this process through which there is rock wastage and land d...

Enzymes are the chemical catalysts that control verious biochemical reactions, without themselves being changed or utilized in the living beings . Beadle(1948) define enzyme as indispensable compound that play a key role in metabolism by bringing direction and control to the physiological process of living cells.Any change in enzyme component of living cell is immediately reflected changed in the physiological and biochemical process of cell. According to Fairley and Kilgour(1966) biological catalysts are called enzyme and with no known exception ,all enzymes are protein. Devlin(1970) also define the enzymes as organic catalysts which increase the rate of biochemical reactions.All enzymes are protein ,but all proteins are not enzyme . Most of the enzymes produced by all,function within that cell and hence are called intracellular or endoenzymes .However some enzyme are released by living cells and catalize reaction in the cell environment such enzyme are known as extracellular or e...

Nucleic acid :       Nucleic acid molecules are long chain polymers of nucleotides.The nucleic acid are considerable important biological system .Each of nucleic acid consists 3 component .ie Pentose sugar,Nitrogen base,Phosphate. Similarly nucleic acid are of two type.ie Ribose nucleic acid(RNA) and Deoxyribose nucleic acid(DNA). Deoxyribose nucleic acid(DNA):        DNA is a nucleic acid containing the genetic instruction used in the development and functioning of all known living organism .Along with RNA and protein DNA is one of the 3 major macromolecules that are essential for all known forms of life. Ribose nucleic acid(RNA):     RNA is function in converting genetic information from genes into a amino acid sequence of protein .There are 3 universal type of RNA ie transfer (tRNA),messenger(mRNA), ribosomal(rRNA) Artificial nucleic acid are analogous has been designed and synthesis by chemist and include peptied nucleic acid,morph...

Tissue culture is the art of growing aseptically isolated plant part as explant in a appropriate medium .A german botanist Gottlieb Haberlandt 1902 gave the concept of tissue culture .Tissue culture involve in vitro culture of any living tissue of the plants on suitable nutrient medium .The culture tissue accelerate to produced cellus(undifferentiated mass of cell) .The is again cultured(subcultured) on suitable nutrient media to induce it for forming embryoids which are than grown into plantlets.The plantlets formed in cultured medium can be transferred to the soil on earthen pots or field . several type of media have been recommended to use for successful tissue culture.Since every tissue or organ has it special requirement for optimal which indeed to be workout .The most media contains a mixture of inorganic salts (to supply macro and micro elements ),vitamin and sucrose.such medium is commonly called as basal medium . The ability or the capability of a plants cell to develop into...

भन्छन् राजनीति सम्भावनाको खेल हो।यहाँ कहिले कतिखेर कुनबेला को सित सहमति गर्छ पत्तो पाहिदैन येस्तो केबल नेपाली राजनीतिमा मात्र देख्न पाहिन्छ।चाहे तो हिजोको कांग्रेस -माओवादी गठबन्धन होस् या अहिलेको बाम गठबन्धन ।                हिजो सम्म एक ले अर्कोको बिरोध गर्ने हरुको मिलन को मुल बिषय के हो भन्दा प्रत्यक्ष निर्वाचित कार्यकारी शाशन प्रणालीको नेपालमा सुरुवात र तत्कालीन संसदिय ब्यबस्थाको खारेजी नै हो।त्यति मात्र नभएर माओवादी को गिरेको साख जोगाउने र नेपालमा शक्तिशाली कम्युनिष्ट सरकारको गठन हो भन्न सकिन्छ ।अझ यो पुरै उत्तरी छिमेकीको देन भनेर आरोप नलागेको भने होईन । बर्तमन अबस्थामा हेर्ने हो भने यो गठबन्धन केबल चुनावी तालमेल मात्र हो किनभने नेपाल कम्युनिष्ट एकता अलि असम्भव कुर जस्तै हो यहाँ कम्युनिष्ट हरु जुट्नेने त फुट्ने खेलहरु चलिरहेकै छन् ।आफ्नो स्वार्थ र पद र पैसाको लोभ मा पार्टी फुटाउने हरुको कमि छैन येस्को उदाहरण नयाँ शक्ति नेपाल का संयोजक बाबुराम भट्टराईले दिई सकेका छ ।बाम गठबन्धन गरेको केहि हप्तामै उनी उक्त गठबन्धन तोडेर कांग्रेस संग मिलिस...

Asymbiotic organism are those that live independently and carry on their life processes without the help of other organism .Some of the soil bacteria that are capable of utilizing atmospheric nitrogan.Eg Achromobacter,Aerobacter,Azotobacter,Beijerinckia,Clostridium,Granulobacter,Pseudomonas and Radiobacter.Among them Azotobacter,Clostridium and Beijerinckia are more important organism as they fix more amount of Nitrogen.The estimated amount of N2 fixation was 700mg/m^2/y^2.But symbiotic association fix 500kg of nitrogen.        The non symbiotic organism are divided into 2 .They are Anareobic and aerobic. Anaerobic bacteria :             Clostridium is the most important bacteria in anaerobic section which is first isolated by Winogradsky in 1891 and named as Clostridium pasterurianum.It is spore forming bacteria  .About dozen species of Clostridium are isolated and it is more abundant than Azotobacter but fix less nitrogen. Aer...