Jumat, 04 Mei 2012

Diposting oleh Unknown di 01.29 0 komentar

“Budidaya Mangga”
Penulis            : Kusno Waluyo
Penerbit          : Epsilon Grup
Jumlah Halaman         : 50 Lembar
Rangkuman
       Tanaman mangga (Mangifera indica L) menyebar dari Asia, kemungkinan besar dari India. Menurut sebuah tulisan yang diterbitkan tahun 1958, di India terdapat kira-kira dua juta akre tanaman mangga (1 akre = kira-kira 0,5 hektar).
       Penyebaran mangga komersil di Indonesia terpusat di pulau Jawa dengan sentra-sentra di provinsi Jawa Timur (Probolinggo, Pasuruan, Gresik), Jawa Tengah (Semarang, Kudus), dan Jawa Barat (Indramayu, Cirebon, Karawang, Subang, Majalenka, Sumedang, Garut, dan Kuningan)
Mangga merupakan komoditi yang tergolong eksotik dan digemari baik didalam negeri maupun luar negeri. Buah mangga cukup penting baik ditinjau dari segi ekonomi maupun kandungan gizinya terutama kandungan vitamin A, B, dan C yang relative tinggi menbuat mangga bermanfaat bagi kesehatan.
Morfologi Tanaman Mangga
>> Daun
Mangga berdaun tunggal, tanpa anak daun penumpu. Letaknya bergantian ranting. Panjang tangkai daun bervariasi antara 1,25-12,50 cm.

>> Batang
Batang pohon mangga tegak, berdahan, bercabang, dan beranting banyak. Cabang dan ranting mangga berdaun lebat sehingga menbentuk tajuk berbentuk kubah, oval, atau memanjang.
>> Bunga
Tanaman mangga menyerbuk silang melalui serangga lebah madu (Apis mellifera). Umumnya bunga terdapat dalam tandan atau rangkaian.

>> Buah
 Buah mangga relative besar, bentuknya ada yang bulat, bulat telur hingga bulat memanjang. Panjang buah mencapai 13 cm.
>> Biji
Bijinya besar, gepeng, diliputi oleh daging buah yang tebal dan lunak  serta enak dimakan. Bijinya berkulit tebal dan liat, tetapi tidak tahan disimpan lama.
>> Akar
Memiliki akar tunggang dan akar samping yang dalam dan kuat. Akarnya sangat panjang, dapat mencapai 6m dalamnya.
Jenis Dan Varietas Mangga
>> Golek
Pohonnya tidak begitu besar, tingginya kira-kira 9 m, tajuk pohon bulat dari garis tengahnya kira-kira 13m. Bunganya merupakan bunga majemuk berwarna kuning. Masa berbunga pada bulan Juli-Agustus dan masa panen pada bulan September-November.
>> Arumanis
Mangga yang berasal dari daerah Probolinggo, Jawa Timur ini merupakan salah satu varietas unggul yang telah dilepas oleh Menteri Pertanian. Buahnya berbentuk jorong, sedikit berparuh, dan ujungnya meruncing.
>>  Mangga Madu
Disebut mangga madu karena rasanya manis seperti madu lenah. Daging buah yang sudah masak berwarna kuning. Bagian dalam kuningnya makin tua seperti warna madu. Serat daging buah sedikit.
..>> Mangga Gedong
Daerah Cirebon dan sekitarnya merupakan asal mangga ini. Bentuk buah bulat dan pangkal buah sedikit miring. Warna buah bintik-bintik putih kehijauan. Daging buah tebal, kenyal, dan berserat halus.
>> Mangga Dermayu
Bentuknya bulat, pangkal berkulat. Warnanya bintik-bintik kehijauan. Daging buah tebal, kenyal, dan berserat halus.
>> Mangga Gadung
Mangga ini banyak ditemukan di sentral produksi mangga di Jawa Timur, yaitu di Probolinggo.
>> Mangga Manalagi
Daerah Pasuruan, Jawa Timur, merupakan asal mangga ini. Buahnya berbentuk jorong, pangkal meruncing, ujung menbulat, dan berparuh jelas.
>> Lalijiwa
Berat buah ini 200 g per buah, berentuk bulat panjang, panjangnya sekitar 7 cm. ujung buah bulat, berparuh sedikit, sedikit berlekuk.
Pedoman Budidaya Mangga
1.      Syarat tumbuh
Tanaman mangga dapat tumbuh baik didaratan rendah atau dingin, sedikit hujan atau banyak. Berikut syarat tumbuh tumbuhan mangga :
·       Temperatur 24 – 27˚c
·       Tanah yang gembur
·       Curah hujan minimal 1000 mm dan musim kering 4.6 bulan per tahun.      
2.    Perbanyakan pohon mangga
Perbanyakan pohon mangga dapat dilakukan sbb. :
·       Generatif
Generatif merupakan perbanyakan secara seksual dengan menggunakan biji.
·       Vegetatif
Vegetatif merupakan perbanyakan secara aseksual, dapat melalui setek, cangkok, atau runduk.
·       Kombinasi
Kombinasi merupakan gabungan antara perbanyakan generatif dan vegetatif.
3.    Pengelolaan Tanah
Pengelolaan tanah disesuaikan dengan keadaan tanah, dilakukan dengan garu, cangkulan atau traktor.
Setelah pengelolaan tanah selesai, dibuat tanda dengan kayu pada tempat yang akan ditanami. Lubang untuk tanaman mangga berukuran 60 x 60 x 60 cm, jarak tanaman 8-12 m. Tanah bagian atas dipisah dengan tanah bagian bawah.
4.   Penanaman
 Waktu penanaman, sebaiknya pada sore hari agar bibit tidak layu, jarak tanaman yang digunakan yaitu 12 x 34 m atau 13 x 13 m.pada waktu bibit akan ditanam, polibag dilepas dengan hati-hati agar tanah tidak sampai pecah.
Pada wwaktu menanam diusahakan akar tersebar seperti keadaan aslinya, akar tunggang jangan sampai membengkok. Tanaman dimasukkan sedikit demi sedikit sehingga tanah bisa masuk di antara akar. segeralah menyimpan tanah yang telah ditanam sampai betul-betul basah lalu dibuat peneduh yang terbuat dari daun kelapa, alang-alang, atau lainnya sehingga tidak terkena sinar matahari langsung.
5.     Pemeliharaan
a.       Penyiraman
b.       Penyiangan & penggemburan
c.       Pemangkasan
a)     Pemangkasan bentuk
b)     Pemangkasan pemeliharaan
d.       Pemupukan
e.       Pencegahan penyakit & pemberantasan hama.

Nama  : Auliya Sari
Kelas   : RSBI 8 C
No.urut/Nis : 06/10081





Kamis, 03 Mei 2012

Photosynthesis

Diposting oleh Unknown di 02.37 0 komentar
Photosynthesis comes from the word photon meaning light, and synthesis of the means set. So photosynthesis can be interpreted as a preparation of complex chemical compounds that require light energy. Energy source of natural light is the sun. This process can take place because of a certain pigment with materials CO2 and H2O. Sunlight consists of several spectra, each spectrum have different wavelengths, so the effect on the photosynthetic process is also different (Salisbury, 1995).
Photosynthesis is a complex biological process, this process uses solar energy and light that can be utilized by the chlorophyll contained in chloroplasts. Such as mitochondria, chloroplasts have an outer membrane and inner membrane. Membrane in the surrounding stroma containing an enzyme that dissolves in the membrane structures called thylakoid. The process of photosynthesis is affected by several factors such as water (H2O), CO2 concentration, temperature, leaf age, translocation of carbohydrates, and light. But the major factor that photosynthesis can take place is light, water, and carbon dioxide (Kimball, 1992).
Although photosynthesis may take place in various ways in various species, some of the characteristics are always the same. For example, the process always starts with the light energy absorbed by chlorophyll proteins called photosynthetic reaction center. In plants, protein is stored in organelles called chloroplasts, whereas in bacteria, these proteins are stored in the plasma membrane. A portion of the light energy gathered by chlorophylls is stored in the form of adenosine triphosphate (ATP). The remaining energy is used to separate electrons from a substance such as water. These electrons are used in a reaction that converts carbon dioxide into organic compounds. In plants, algae, and cyanobacteria, was conducted in a series of reactions called the Calvin cycle, but a series of different reactions are found in some bacteria, such as reverse Krebs cycle in Chlorobium. Many photosynthetic organisms have adaptations that concentrate or store carbon dioxide. This helps reduce wasteful process called photorespiration which can be spent most of the sugar produced during photosynthesis.
The first photosynthetic organisms likely evolved about 3,500 million years ago, early in the evolutionary history of life when all life forms on Earth are microorganisms and has a large amount of atmospheric carbon dioxide. Living things when it is most likely utilize hydrogen or hydrogen sulfide - not water - as a source of electrons. Cyanobacteria appeared later, around 3,000 million years ago, and drastically change when they start oxygening Earth's atmosphere at about 2,400 million years ago. This new atmosphere enables the evolution of complex life are like protists. In the end, no less than a billion years ago, one of the protists formed a symbiotic relationship with cyanobacteria and produce common ancestor of all plants and algae. Chloroplasts in modern plants are the descendants of this symbiotic cyanobacteria.
The Light Reaction

Light reaction is a process to produce ATP and NADPH2 reduction. This reaction requires water molecules and the light of the Sun. The process begins with the capture of photons by the antenna pigments.
Light reaction involves two photosystems that cooperate with each other, namely photosystem I and II. [38] Photosystem I (PS I) contains the reaction center P700, which means that the photosystem is optimally absorb light at a wavelength of 700 nm, whereas photosystem II (PS II ) containing P680 and the optimal reaction center absorbs light at a wavelength of 680 nm.
Light reaction mechanism begins with the stage where the photosystem II absorb sunlight so that chlorophyll in PS II electron excited states and lead the charge to be unstable. To stabilize the back, PS II will take electrons from H2O molecules around it. Water molecules will be resolved by ion manganese (Mn), which acts as an enzyme. This will result in the release of H + in the thylakoid lumen.

By using electrons from water, then PS II would reduce plastokuinon (PQ) form PQH2Plastokuinon a quinone molecule found in the thylakoid membrane lipid bilayer. Plastokuinon will send electrons from PS II to an H + pump called the cytochrome b6-f complex.  The overall reaction that occurs in PS II are:
                                               2H2O + 4 + 2PQ + photon-4H 4H + + O2 + 2PQH2
Cytochrome b6-f complex serves to carry electrons from PS II to PS I by oxidizing PQH2 and reduction of small proteins that are very easy to move and contain copper, which is named plastosianin (PC).  This incident also led to pump H + from the stroma to thylakoid membrane.  The reaction in the cytochrome b6-f complex is :
                                                 2PQH2 4PC + (Cu2 +) → + 2PQ 4PC (Cu +) + 4 H + (lumen)


Electrons from cytochrome b6-f complex to be received by photosystem I. is to absorb light energy Photosystem apart from PS II, but it contains an integral core complex, which receives electrons from H2O via the PS II core complex in advance.  For systems that rely on light, PS I plastosianin oxidize reduced function and move the electrons to the Fe-S protein called soluble feredoksin.  the overall reaction in PS I is :
                                        Light 4PC + (Cu +) + 4Fd (Fe3 +) → 4PC (Cu2 +) + 4Fd (Fe2 +)

Further electrons from feredoksin used in the final stages of the transport of electrons to reduce NADP + to form NADPH. [38] This reaction is catalyzed by enzymes in the stroma-NADP + reductase feredoksin. [38] The reaction is [38]:
                                        4Fd (Fe2 +) + 2H + + + 2NADP → 4Fd (Fe3 +) + 2NADPH

H + ions that have been pumped into the thylakoid membrane will go into the ATP synthase.  of ATP synthase will compare the formation of ATP with the transport of electrons and H + across the thylakoid membrane.  The entry of H + on the ATP synthase will make ATP synthase worked to change ADP and inorganic phosphate (Pi) to ATP.  overall reaction that occurs in the light reaction is as follows  :
                                       ADP + Pi + light + NADP + + 2H2O → ATP + NADPH + 3 H + + O2
The scheme Z

In plants, light reaction occurs in the thylakoid membrane in chloroplasts and use light energy to synthesize ATP and NADPH. Light reaction has two forms: the cycle and nonsiklus. At nonsiklus reaction, the photons are absorbed in the antenna complex of photosystem II by light-absorbing pigment chlorophyll and other accessories. When the chlorophyll molecules in photosystem II reaction center core obtain sufficient excitation energy from the adjacent antenna pigments, an electron is transferred to electron acceptor molecules, ie feopftin, through a process called separation of power terfotoinduksi. These electrons are transferred through a series of electron transport, the so-called Z scheme, which initially serves to generate kemiosmosis potential along the membrane. One enzyme ATP synthase using kemisomosis potential to generate ATP during photophosphorylation, whereas NADPH is a product of the terminal redox reaction in the scheme Z. Electrons into the chlorophyll molecules in fofosistem II. Electrons are excited because the light is absorbed by the photosystem. The second electron carrier receives electrons, which again is passed to lower energy electrons penerim. The energy generated by the electron acceptor used to move hydrogen ions across the thylakoid membrane to the lumen. Electrons are used to reduce the coenzyme NADP, which has the function of the light reaction. The reaction cycle nonsiklus similar, but differ in shape because it only produces ATP, and no NADP (NADPH) produced reduced. The reaction cycle only lasts in photosystem I. Once the electrons transferred from photosystem, the electron is moved through the electron-accepting molecules and returned to photosystem I, that's where the electron was originally issued, so the reaction is named in the reaction cycle.



                                                             Photolysis of Water

     NADPH is the main reducing agent in chloroplasts, providing a source of energetic electrons to other reactions. Its production leaves chlorophyll with a deficit of electrons (oxidized), which must be obtained from some other reducing agents. Electrons lost from chlorophyll in photosystem I are replaced from a series of electron transport by plastosianin. However, since photosystem II includes the first phase of the scheme Z, an external electron source to reduce molekuk siperlukan its chlorophyll a has been oxidized. Source of electrons in photosynthesis of green plants and cyanobacteria is water. Two water molecules are oxidized by the reaction of the separation-energy four in a row by photosystem II to produce one molecule of oxygen diatom and four hydrogen ions; electrons generated at each stage was transferred to a redox-active tyrosine residue that then reduces the paired species of chlorophyll a has been called the P680 terfotooksidasi useful as the primary electron donor (driven by light) on the photosystem II reaction center. Catalyzed the oxidation of water by photosystem photosystem II by a redox-active structure that contains four manganese ions and one calcium ion; complex evolution of oxygen is bound to two molecules of water and store the equivalent of four that has been oxidized is required to perform water oxidation reaction. Photosystem II is the only enzyme known to carry out biological oxidation of water. Hydrogen ions contribute to the transmembrane potential kemiosmosis that led to the synthesis of ATP. Oxygen is the residue of the reaction product of light, but most organisms on Earth use oxygen for cellular respiration, including photosynthetic organisms.
The Dark Reaction
  Dark reactions in plants can occur via two pathways, the Calvin-Benson cycle and the Hatch-Slack cycle. In the Calvin-Benson cycle plants convert ribulose 1.5 bisphosphonate compound into a compound with three carbon atom number of the compound 3-phosphogliserat. Hence plants that run through the dark reaction pathway is called C-3 plants. Belay CO2 as a carbon source in plants is aided by the enzyme RuBisCO. Plants are dark reactions following the Hatch-Slack pathway is called C-4 plants due to a compound formed after mooring CO2 is oxaloacetate, which has four carbon atoms. Enzymes that play a role is the phosphoenolpyruvate carboxilase.
Calvin-Benson cycle
Mechanism of the Calvin-Benson cycle begins with the fixation of CO2 by ribulose diphosphate carboxylase (RuBP) to form 3-Phosphoglyceric.  is an enzyme RuBP alosetrik stimulated by three types of lighting changes
resulting from chloroplast. First, the reaction of this enzyme is stimulated by an increase in pH.  If the chloroplasts were light, the ion H + is transported from the stroma into the thylakoid result in an increase in pH of the stroma that stimulates enzyme carboxylase, is located on the outer surface of the thylakoid membrane.  Second, this reaction stimulated by Mg2 +, which enters the stroma of leaves as H + ions, if the chloroplasts were light.  Third, the reaction was stimulated by NADPH, generated by photosystem I light during administration. CO2 fixation is a dark reaction is stimulated by light chloroplasts.  Fikasasi CO2 through the process of carboxylation, reduction, and regeneration.  carboxylation involves the addition of CO2 and H2O into RuBP to form two molecules of 3-Phosphoglyceric (3-PGA).  Later in the reduction phase, the carboxyl group in 3-PGA is reduced to an aldehyde group in 3-fosforgliseradehida (3-Pgaldehida).

This reduction does not occur directly, but the carboxyl group of 3-PGA is first converted into the acid anhydride ester type 1.3-bifosfogliserat acid (1,3-bisPGA) with the last addition of phosphate groups from ATP.  ATP was arising from photophosphorylation and ADP is released when the 1.3-bisPGA formed, which rapidly converted back to ATP by the addition reaction of photophosphorylation. reducing the actual material is NADPH, which accounts for two electrons. Taken together, Pi released and re-used to convert ADP to ATP.  

In the phase of regeneration, the regenerated RuBP is required to react with additional CO 2 that diffuses constantly into and through the stomata.  At the end of the reaction of Calvin, a third ATP is required for each molecule of CO2 is tethered, is used to change the ribulose-5 -phosphate to RuBP, then the cycle begins again.

Three rounds will cycle tether 3 molecules of CO2 and the end product is a 1.3-Pgaldehida. Some used the chloroplast to form starch, while others were carried out.  This system makes a constant amount of total phosphate in the chloroplasts, but led to the emergence of triosafosfat in the cytosol.  Used the cytosol trioses phosphate to form sucrose.







                                       Experiments Ingenhousz

Tool :                                                                                     
*    Medium-size bottle of mineral water (pict.1)
*    Timekeeper
Material :
*    Plant of  Hydrilla Verticillata
*    Water
Time :    09.10 Wita until finish        
Place   : Schoolyard of Junior High School 2 Maros

Work Steps of experiment Ingenhousz  :
§     Water bottle with water filled to the brim
§    Enter the plant Hydrilla verticillata into a bottle of mineral water
§   . Close the bottle tightly
§     Place the bottle that had been given Hydrilla plants in areas of direct sunlight
§     Observe what happens
§     After  1 hour later, again observe the changes in the bottle and its content
§     Write the results of observations on a sheet of paper
§     And the conclusion was the result of photosynthesis experiments are you doing.





      




 The Result of Experiment Ingenhousz
day/
date
time
Hour
duration of observation
number of bubbles
Thursday/
05-04-2012
morning
09.10 – 09.11
Wita
1minute
34 bubbles
Thursday /
05-04-2012
Afternoon
12.09 – 12.10
Wita
1minute
121 bubbles
Thursday /
05-04-2012
Afternoon
13.00 – 13.01
Wita
1minute
106 bubbles
Thursday /
05-04-2012
Evening
16.04 – 16.05
Wita
1minute
65 bubbles
Thursday /
05-04-2012
Evening
19.00-19.01
Wita
1minute
no bubble
Important things resulted from the experiment, which are :
§      The gas released by plant is O2
§      Sunlight is needed in the process
§      Only the green part releases 02
          When the bottle containing the  Hydrilla verticillata plant and water, will soon appear bubbles of air that meets the surface of the bottle. Bubbles generated in the experiment was a oxygen. This gas is formed by the photolysis process in which water is decomposed into oxygen gas that will appear in the form of bubbles with the following equation:
                                               2H2O (l) 4H + (aq) + O2 (g)
         Of the equation appears to O2 gas produced from the decomposition of molecules of waterAfter left for one hour under a hot sun in a bottle of water decreases 1 cm and create your bottle becomes bloated and can not stand anymore.


CONCLUSION
          From  experiments have been carried out it can be concluded photosynthesis is a
biochemical process in which plants, algae, and some types of bacteria used to produce energy (nutrients) by utilizing light energy. Almost all living things depend on energy produced in photosynthesis. Photosynthesis is one way in photosynthetic carbon assimilation due to CO 2 bonded carbon-free (fixed) into sugars as energy storage molecules. In photosynthesis, the chemical energy converts carbon dioxide into sugar and takes place in the stroma. Glucose not only provides an energy savings of chemical bonds, but also provide a molecular basis for generating thousands of other molecules needed by plants. Oxygen is released as a byproduct of photosynthesis. The overall chemical process of photosynthesis can be simplified into the following equation:
                               6CO2 + 12H2O + light energy C6H12O6 +6 O2 +6 H2O
Here are some key factors that determine the rate of photosynthesis:
1. Light Intensity
The maximum photosynthetic rate when a lot of light.
2. Concentration of carbon dioxide
The more carbon dioxide in the air, the more the amount of material used DAPT plants to continue photosynthesis.
3. Temperature
Enzymes that work in the process of photosynthesis can only work at optimum temperature. Generally fotosintensis rate increases with increasing temperature up to the tolerance of the enzyme.
4. Water Content
Water shortage or drought cause stomata to close, blocking the absorption of carbon dioxide, thereby reducing the rate of photosynthesis.
5. Fotosintat Levels (of photosynthesis)
If fotosintat such as reduced carbohydrate levels, photosynthetic rates will rise. If levels of fotosintat increases or even saturated, the rate of photosynthesis will decrease.







                                                                                  

















                                      


 

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