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1580
Hypothesis for plant growth
Jan Van Helmont made a hypothesis on the data he gathered that in order for a tree to grow and gain mass, it must obtain food from somewhere else, this is because he weighed a tree and its soil for five years and while the tree got bigger and heavier the soil was the same weight -
Publication of book plant anatomy
Marcello Malpighi publishes a book called Anatomia Plantarum (Plant Anatomy), which was an exhaustive comparative study of plants containing many excellent drawings. Among Malpighi's many contributions to plant anatomy was the discovery of stomata, the pores of leaves. -
Jan Ingenhousz discovers light is necessary for oxygen
The same experiment was done by Priestley with a candle and a plant in a bell jar, except he covered the jar so no light could enter, he left it for a few days and then tried to light the candle with no successful lighting, this allowed him to make his conclusion that light was needed for the 'fouled air' taken up by the candle to be turned back to normal air. -
Oxygen and light
Jan Ingenhousz submerged plants under sunlight and then put them under the shade, and he noticed that small bubbles were produced by the plant in the sunlight, after putting it under the shade the bubbles stopped and Jan Ingenhousz concluded that plants use light to create oxygen -
How plants can produce oxygen
Joseph Priestley publishes his findings on how plants could be used to restore air that was "injured" (turned to carbon) by a candle by putting a candle in a jar and watching as the flames went out after closing the lid of the jar -
Absorbtion of carbon dioxide
Jean Senebier demonstrated that plants absorb carbon dioxide and release oxygen with the help of sunlight, in 1800 he demonstrated that light is the agent responsible for the fixation of carbon dioxide and that oxygen is liberated only in the presence of carbon dioxide -
Growth of plants is not only carbon
Nicolas-Théodore de Saussure demonstrated that while plants need carbon dioxide, the increased mass of growing plants is not the result of carbon dioxide alone but also the uptake of water -
Plants making energy
Julius Robert Mayer proposed that plants convert light energy into chemical energy due to energy can be neither created nor destroyed -
Starch in plants
Julius Sachs investigated how starch is produced under the influence of light and in relation to chlorophyll and later proved that the starch present in the chloroplasts results from the absorption of carbon dioxide, and he established that starch is the first visible product of photosynthesis -
Cohesion Adhesion Tension Theory
The theory was proposed by Dixon and Joly in 1894, and Askenasy in 1895, supported by Renner in 1911, Curtis and Clark in 1951, Bonner and Galston in 1952, and Gramer and Kozlowski in 1960. It describes the movement of water from roots to leaves, this is done by water molecules bonding to each other by hydrogen bonding, it forms a string of molecules during its movement toward the xylem. The water molecules stick
together and get pulled up by tension due to the evaporation of water. -
Photosynthesis word equation
Cornelis Van Niel proposed the general equation for photosynthesis CO2 + 2H2A + Light energy → [CH2O] + 2A + H2O