Physiology from Greek physis nature origin and logos

Physiology (from Greek: φυσις, physis, “nature, origin”; and λόγος, logos, "speech" lit. "to talk about the nature (of things)") is the study of the mechanical, physical, and biochemical functions of living organisms.

Plant Physiology Definition The Early Years Environmental Effects on Plant Growth – Light Photosynthesis/Respiration Phototropism/ Photoperiodism Other Plant Physiology Early Years Van Helmont Joseph Priestly Essential life processes that determine how plants grow and develop

Sir Francis Bacon published one of the first plant physiology experiments in 1627 in the book, Sylvarum. Bacon grew several terrestrial plants, including a rose, in water and concluded that soil was only needed to keep the plant upright. Jan Baptist van Helmont published what is considered the first quantitative experiment in plant physiology in 1648. He grew a willow tree for five years in a pot containing 200 pounds of oven-dry soil. The soil lost just two ounces of dry weight and van Helmont concluded that plants get all their weight from water, not soil. In 1699, John Woodward published experiments on growth of spearmint in different sources of water. He found that plants grew much better in water with soil added than in distilled water. Stephen Hales is considered the Father of Plant Physiology for the many experiments in the 1727 book[8]; though Julius von Sachs unified the pieces of plant physiology and put them together as a discipline. His Lehrbuch der Botanik was the plant physiology bible of its time. [9] Researchers discovered in the 1800 s that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil are dissolved in water, plant roots absorb nutrients readily, soil is no longer required for the plant to thrive. This observation is the basis for hydroponics, the growing of plants in a water solution rather than soil, which has become a standard technique in biological research, teaching lab exercises, crop production and as a hobby

Plant physiology is a subdiscipline of botany concerned with the function, or physiology, of plants. [1] Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, and molecular biology. Fundamental processes such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed germination, dormancy and stomata function and transpiration, both part of plant water relations, are studied by plant physiologists.

Plant physiology: It is a branch / sub field/ discipline of botany that deals with plant structure. Functions and process in relation Physiology : Study of life process to environment. Structure : Plant parts / tissue / cell / organs, and their association with process. Ex: Leaf anatomy, root stem stomata etc. Process: A series of sequential events operating under natural conditions. Eg: Stomatal mechanism, Ascent of sap, Photosynthesis & respiration. These process are explained and described. Functions: Natural activity of a cell/tissue / organ etc. which are manifested at cell level. Eg. Photosis _ Leaf In this science study the factors modifying /affecting the growth and development. or how external stimulii/ factors modify the plant responses. ie G*E inter action : Stress / heat / cold. A comprehensive information on the structure, processes functions at tissue / cell / organ is described in order to explain the process like growth and development of plants in relation to environment.

The field of plant physiology includes the study of all the internal activities of plants— those chemical and physical processes associated with life as they occur in plants. This includes study at many levels of scale of size and time. At the smallest scale are molecular interactions of photosynthesis and internal diffusion of water, minerals, and nutrients. At the largest scale are the processes of plant development, seasonality, dormancy, and reproductive control. Major subdisciplines of plant physiology include phytochemistry (the study of the biochemistry of plants) and phytopathology (the study of disease in plants). The scope of plant physiology as a discipline may be divided into several major areas of research. Five key areas of study within plant physiology.

Scope: Studies of plant physiology dates back when man realised and started exploitation of plants for his use. Today, it is well developed science based on scientific facts. Plants require for his co existence, for that, plant physiology has to be explored or developed in order to improve the plant wealth. For this we should know. How plants work & what is the influence of environment on plant growth and development. 1 plant physiology becomes basis for the technology / advances in Agri. Forestry & Poultry. The inherent potential can be exploited only after knowing the physiological responses to physical environment( G x E). 2 It helps in solving the problems like rooting, cutting, pre&-post harvest, abscission senescence, dormancy, Flower syncronisation, defoliation, weed control, tissue culture, modification of plant growth structure (bolting) etc. 3 Identification of physio – morphological architecture / ideotype for high yield for given situation. 4 To device a strategies to over come productivity constraints. Efficient utilisation of natural resources 5 Identification of economically important plants / parts or under exploited crops. 6 To decide natural requirement ex : nutrient 7 Identification of traits for yield 10% etc. 8 Standardisation of tissue culture techniques 9 Modification of plant growth by hormones x nutrients 10 Standardisation of propagation, handling, harvesting, storage, season etc. 11 allelopathy, pest & disease management human health risk weedicides etc. However, there is a greater need of strengthening physiological research through which crop cultivation can be re modeled on the basis of scientific facts for better adaptability modernisation of crop husbandry. Ex: Temperature

Role of plant physiology in agriculture Plant physiology serves as the foundation for the numerous recent advances in agriculture, horticulture and forestry. Plant physiology has an important role in agricultural research programmes in the near future. Basic aspects of plant physiology can be applied in the crop improvement programme for obtaining greater yields. The following are some of the applied areas of plant physiology. 1. Production physiology. Net photosynthetic rate Total photosynthetic surface (LAI) . Leaf area duration (LAD) Source sink relationship Assimilate partitioning during vegetative stage Global warming 2. Stress physiology 3. Growth regulators physiology 4. Nutriophysiology

A. Production of oxygen gas as a by-product of photosynthesis. The first oxygen producers were thought to be bacteria (like today’s cyanobacteria), which were eventually incorporated as endosymbionts into plant ancestors. You can’t have eukaryotes without oxygen (so aren’t we all glad it’s there!) Maybe we’ll take a field trip to an oxygen bar, like this one in Seattle, where customers pay $1/minute to breath 97% O 2.

• What is a Plant? • Surely, then we can say that anything that does photosynthesis • is a plant, right? • Nope. But I’m being pickier than • many people when I say that. • If you want to know much more • about it, take systematic botany; • but for now, to be a plant you • have to have chlorophylls a and b, • store sugar as starch, and have an ancestor that had two • anterior whiplash flagellae with star-shaped bases

What is a Plant? So what is a plant? My definition includes everything from “green algae” to flowering plants, which are considered the most advanced plants. Our focus will be on the land plants, like ferns, coniferous and deciduous trees, grasses, and wildflowers, to name a few.

Atmospheric gas regulation B. Oxygen gas (O 2) in the atmosphere is converted to ozone (O 3)in the stratosphere, as it absorbs UV light. Ozone then absorbs more UV light and is eventually converted back into oxygen gas. This process blocks up to 99% of all the harmful UVB rays that would otherwise sterilize the surface of the earth impossible, by causing so many mutation in anything that ventured out of the shade

C. Utilization of CO 2. Plants use carbon dioxide to build sugar via the Calvin cycle (a. k. a. “dark reactions”) of photosynthesis. Besides being toxic to humans at elevated levels (as the crew of Apollo 13 nearly experienced), CO 2 is a “greenhouse gas, ” meaning that it absorbs infrared radiation from earth, keeping that energy the atmosphere to global warming. in longer and contributing

Why Study Plants? Sugars and their polymers A. “Carb’s are the enemy, ” according to Dr. Atkins, right? I don’t buy it, but then again I’m not losing weight, either. Plants give us simple sugars as well as starches. Even if your on a low-carb diet, you can still thank plants for all the leafy greens you’re (hopefully) eating. And then there’s the fact that all the meat you eat was part of an animal that probably ate plants to live. So almost all our food comes from plants

Why Study Plants? B. Fibers-1. Cotton: As George Costanza showed the Yankees on Seinfeld, cotton is king. 2. Paper: Average paper use person in North America is 2 kg/day. 3. Fibers such as nylon and rayon are processed from wood fibers.

Why Study Plants? III. Other molecules IV. A. Medicines Foxglove produces digitalis, which treats heart disease. Taxol from the bark of the pacific yew tree is one of the most promising anti-cancer drugs. Rosy periwinkle from Madagascar treats two cancers: juvenile leukemia and Hodgkin’s disease. Threatened by increasing V. Also noteworthy are aspirin, ephedra (banned), population. VI. quinine, ginkgolides, and others.

Why Study Plants? B. Spices C. Oils D. Essential amino acids--There are 8 amino acids that we need in our cells, but we don’t have the ability to produce them ourselves. We can most easily get them from plants. To get the complete set of essential amino acids, a combination of legumes and cereals is best. What does that mean? E. Fossil fuels like coal, crude oil, and natural gas are the products of plants that died a long time ago

Why Study Plants? F. I would be remiss not to mention one of the most economically and culturally important “other molecules” that is made from plants… alcohol.

BASIC PRINCIPLES OF PLANT PHYSIOLOGY There are number of basic postulates/generalization about science in general and pl. physiology. In Particular. 1)The plant function/process can only be under stood on the basis principles of Physics biochemistry/Anatomy/Statistics Development of these sciences has contributed to the evaluation/discovery of several instrument/techniques, which helped in the elaboration of plant anatomy. 1)Eg. Gass exchange law of deffusin. antimetalolits, chromatography, scaning, Eletrophorosis electron microscope/mass spectro metry etc. electrophorosis, contrifugal Contrifugation: have addition the elaboration of several process, Properties of gasses, solids. Chemistry; Helps in identifying organic chemicals their properties, reactions, that takes place in the biological systems. Anatomy: Structural organisms of cell/tissue to under stand, process like phases, resp- transpiration unless we know the cell/organellae tissue with which there associated C 4. Kantz type.