Light and temperature, light and temperature as ecological factors

Light and temperature, light and temperature as ecological factors.
Abiotic components or abiotic factors are non-living chemical and physical parts of the environment.
Light and temperature || MAJOR Abiotic Factors.
Abiotic factors are the non living components of an ecosystem and they influence the survival of organisms.
Light intensity or light quantity refers to the total amount of light that plants receive. It is also described as the degree of brightness that a plant is exposed to.

1. LIGH & TEMPERATURE Sehrish Qayyum 017948

2. LIGHT & TEMPERATURE Quality of light diurnal and seasonal variation ecophysiological responses

3. CONTENTS Defination Importance Light Quality Types Units Of Light Methods Of Measurment Diurnal & Seasonal Variation Eco physiological Responses Conclusion Questions

4. LIGHT DEFINATION: Light is the most essential Abiotic factor without which the life cannot exist. EXAMPLE : The chief natural source Of light is SUNLIGHT .

5. IMPORTANCE OF LIGHT Light plays important role in the life of plants. It provides energy to maintain life on earth. It is absorbed by chlorophyll in green plants and converted into chemical energy contained in simple sugar molecule . It influences morphology and anatomy of plants. It exerts many stimulating effects upon plants ,especially upon the differentiation of tissues and organs . It also effects the physiologic processes such as transpiration, photosynthesis, photo periodism, phototropism, and chemical composition of plants.

6. LIGHT QUALITY Light quality also called spectral composition and Spectral energy distribution (SED) refers to the composition Of light as to wavelengths that are effective in , Photosynthesis and other Plant growth processes. PHOTOSYNTHESIS AND OTHER PLANT GROWTH PROCESS.

7. TYPES OF LIGHT There are three types of light. Ultraviolet radiation Visible spectrum Infrared radiation According to Dalvin (1975),the wavelength between 300nm to 900 nm are capable of effectively plant growth however, it is not allows light quality that effects plant growth process other Properties light intensity & light duration involved.

8. SUNLIGHT %AGE ULTRAVIOLET 3% INFRARED 53% VISIBLE LIGHT 44% Most of the sunlight that reaches the upper atmosphere is filtered or reflected back to Outer space so that only a small portion reaches the earth.

9. ULTRAVIOLET RADIATION DEFINATION: Wavelength less than 390 (mill microns) are too Short to be seen and known as, Ultraviolet radiation. They are very active in certain chemical reaction. However these are not required by the plants.

10. CHARACTERISTICS Packed excessive amount of energy. Break bonds and destroy organic materials. Absorbed by o2 & o2. Shorter wavelength than visible light. Can kill living cells. Causes skin cancer.

11. VISIBLE SPECTRUM DEFINATION : The range of light waves that we can see is known as visible spectrum. The visible light lie from ( 400 nm to 750 nm ). The (PAR) photosynthically Active radiation range is 171 to 299 kg per mole photon.

12. VISIBLE LIGHT COLOURS VISIBLE LIGHT COLOURS ARE: VIOLET BLUE , GREEN ,YELLOW , ORANGE & RED. RED LIGHT: EXTREME PART OF THE RED REGION . ( WAVELENGHT 700nm) WHITE LIGHT : ALL THE WAVELENGHT PRESENT. DARK LIGHT: NO,VISIBLE WAVELENGHT.

13. WAVELENGTH SERIES When sunlight is passed through a Prism it is dispersed into a series of wavelength. RED LIGHT : (750 TO 626 MILLIMICRON) ORANGE LIGHT : (626 TO 595 MILLIMICRON) YELLOW LIGHT : (595 TO 574 MILLIMICRON) GREEN LIGHT : (574 TO 490 MILLIMICRON) BLUE LIGHT : (490 TO 435 MILLIMICRON) VIOLET: (435 to 400 mill micron) These colors of light effect most physiologic processes of plants such as, photosynthesis .

14. INFRARED RADIATION DEFINATION: THE WAVELENGTHS LONGER THAN THE 750nm ARE CALLED INFRARED: STEPS: These radiations produced heat ,and can be detected by by animals because of sensation of heat. These infrared radiations (longer than 750nm ). Are important biologically as these influence Hormones governing germination & responses To day length (photo periodism).

15. CHARACTERISTICS It is participate in photosynthesis and other plant reaction . Responsible for warm temperature . Make the earth comfortable for man and other organism as, plants. Absorbed by cells ,but energy is too low to exist the electron.

16. UNITS OF LIGHT THE WAVELENGTH OF LIGHT ARE EXPRESSED IN SMALL UNITS OF DISTANCE SUCH AS, (MICRO) & (MICROMETER) ( MONOMETER ) &( ANGSTROM ) 1 MICRON = ONE MELIONTH OF A METER . (10-6 METER)

17. METHODS OF MEASUREMENT There are five methods of measurement. Radio meter Spectrophotometer Photo electric cell Photo chemical method The secchi disk

18. SECCHI DISK

19. DIURNAL & SEASONAL VARIATION

20. DIURNAL CYCLE A diurnal cycle is any pattern that recurs every 24 hours as a result of one full rotation of the earth around its own axis. In climatology ,the diurnal cycle is one of the most basic form of climate patterns. The most familiar such pattern is the diurnal temperature variation.

21. ENVIRONMENTAL CONDITINS Diurnal cycle of environmental conditions (Light or temperature) can result in similar cycles independent biological processes. Such as, Photosynthesis in plants. & Depression in human. Environmental cycles may even induce indirect cycle in rhizosphere,& nitrogen- Fixation.

22. SEMI DIURNAL CYCLE A semi diurnal cycle refers to a pattern that Occurs about every twelve hours or about twice a day. Often these can be related to lunar tides, In which case the interval is closer to 12 hours and 25 minutes.

23. SEASONAL VARIATION In invitro culture seasonal variation is also affected such as relative humidity, Dry season. When to dry nutrient medium evaporates rapidly . In extreme most climate such as, Poor tropical region fungi is effected on media.

24. Dust in air is also a major source of bacterial contaminants. small insects insects that enter incubation room through undetermined avenues is also effects the culture tube . germination of roots and shoots also delayed due to seasonal variation.

25. VARIATIONS IN SEASON In four seasons variations are different such as , spring season. Summer season. Autumn season & winter season.

26. SPRING SEASON Spring is one of the four conventional temperate season. When spring in the Northern Hemisphere the autumn in the Southern Hemisphere. in spring the days grow longer the air gets warmer in some places the weather is rainy. Birds builds nests and lay eggs. Plants and trees are begin to bud. The leaves begin to grow on leaves.

27. SUMMER SEASON Summer is the hottest of the four temperate seasons, Falling between spring and autumn. At the summer solstice , the days are longest and the nights are shortest. With day-length decreasing as the season progresses after the solistice. The date of the beginning of summer varies according to climate, When it is summer in the northern hemisphere , it is winter in the southern hemisphere , and vice versa.

28. AUTUMN SEASON Autumn is one of the four temperate seasons . Autumn marks the transition from summer to winter ,in September (Northern hemisphere) or march (southern hemisphere) When the duration of day light becomes noticeably shorter And the temperature cools down considerably, One of its main feature the shedding of leafs from deciduous trees.

29. WINTER SEASON Winter is the coldest season of the year in polar and template Climates, between autumn and spring . Winter is caused by the axis of the earth in that hemisphere Being oriented away from the sun. Different cultures define different dates as the start of winter, And some use a definition based on weather. When it is winter in the northern hemisphere, It is summer in the southern hemisphere, and vise versa. In many regions ,winter is associated with snow and freezing temperatures.

30. ECOPHYSIOLOGICAL RESPONSES Light effects a number of physiologic and ecologic responses of the plants such as, Photosynthesis. Transpiration. Seed germination. Photo periodism. Reproduction and growth. Effects on structure of plant.

31. PHOTOSYNTHESIS DEFINATION : P hotosynthesis is a process used by plants in which energy from sunlight is used to convert carbon dioxide and water into molecules needed for growth. These molecules include sugars, enzymes and chlorophyll. Light energy is absorbed by the green chemical chlorophyll.

32. At low light intensities ,as light intensity increases, the rate of light- dependent reaction , and therefore photosynthesis generally ,increases proportionality. (Straight line relationship) T he more photons of light that fall on a leaf ,the greater the number of chlorophyll molecules that are ionized and the more (ATP) and (NADPH) are generated. Light dependent reactions use light energy and so are not affected by changes in temperature.

33. TRANSPIRATION Defination: Transpiration is the process of water movement through a plant and its evaporation from aerial part. Such as, Leaves stems and flowers.

34. High light intensity promotes transpiration light stimulates the guard cells to open and increase the permeability of the plasma membranes. Of the total light energy reaching leaves about one-third is reflected back and about two- thirds is absorbed. Heat energy used up in the vaporization of water.

35. SEED GERMINATION DEFINATION: Seed germination is the process by which an plant grows from a seed or similar structure. EXAMPLE : The most common example, of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm

36. The seed of most plants become sensitive to light when wetted in some cases they germinate whereas in other cases the germination is retarted. Example: Lactuca (salad) seeds will not germinate without light stimulation .

37. PHOTOPERIODISM DEFINATION: Photoperiodism is the physiological reaction of Organisms to the length of the day. OCCURANCE : IT OCCURS IN PLANTS AND ANIMALS

38. Twelve to fourteen hours of day light is critical duration for most plants the plants may be long day or short day plants . The stimulus is received by a pigment called photochromic. Photoperiodism help plants to detect seasons . It also effects the distribution of plants .

39. REPRODUCTION AND GROWTH DEFINATION: Plant reproduction is the Production of new individuals Or offspring in plants ,which can be sexual or asexual reproduction. Plant growth is the process by which the plant grows in size.

40. In sufficient light super presses flowering and the vascular plants may remain vegetative indefinitely. Fungi requires light for production of spores. The crops grown for vegetative parts are favored by cloudy climates whereas, fruits, grains, and seeds are favored by bright sun.

41. EFFECT ON STRUCTURE OF PLANT The amount of light available to a plant exerts a notable influence on the structure and function of the organs. The process of differentiation is governed by blue & violet wavelengths of light. Plant growing in full sunlight have a thick stem, profusely branched ,less leaf area per plant, and smaller cells in leaf blades,

42. Thicker cuticle, fewer and smaller chloroplasts, better developed palisade longer and more branched roots, etc . T heir photosynthetic rate is higher, transpire rapidly, show greater vigor of flowering , & fruiting produce seeds with more calories per gram dry weight, and are more resistant to temperature, injury , drought and parasites.

43. ECOLOGICAL CLASSIFICATION According to relative requirements of Sunlight or shade . The plants may classified ecologically as following. Heliophytes. Sciophytes. Facultative sciophytes. Obligative heliophytes

44. HELIOPHYTES & SCIOPHYTES HELIOPHYTES: The plants that grow best in full sun light is called heliophytes . SCIOPHYTES: The plants that grow best at low Light intensity are known as Sciophytes.

45. FACULTATIVE SCIOPHYTES & OBLIGATIVE HELIOPHYTES FACULTATIVE SCIOPHYTES: Some heliophytes can grow fairly well under shade they are known as, FACULTATIVE SCIOPHYTES. OBLIGATIVE HELIOPHYTES: Similarly, some sciophytes can grow better in full sunlight, these are known As, obligative heliophytes.

46. CONCLUSION Do you think about what would happen if plants do not get enough sun? Would they grow the same? I f the amount of sun increases,then the plant growth will also increase Because light helps plant grow.

47. QUESTIONS WHAT WILL HAPPENS TO PLANTS IF THERE IS NOT ENOUGH SUNLIGHT? WHY DO PLANTS GROW TOWARDS THE LIGHT?