PLANT PHYSIOLOGY BY NIKHIL PURANIK
ABOUT MIE MY NAME IS NIKHIL PURANIK PURSUING B.E IN MECHANICAL ENGINEERING FROM RNSIT LIVE IN BENGALURU PROFILE :https://unacademy.com/user/nikhilrpuranik
TOPICS COVERED WHAT IS PHYSIOLOGY TRANSPORT IN PLANTS TRANSLOCATION DIRECTION OF TRANSPORT MEANS OF TRANSPORT DIFFUSION FACILITATED DIFFUSION ACTIVE TRANSPORT
WHAT IS PHYSIOLOGY? It is the branch of biology that deals with the normal functions of living organisms and their parts, including all physical and chemical processes. FRENCH LATIN GREEKphysiologia phusiologia natural philosophy physiology early 17th century ENGLISH physio- -logy
TRANSPORT IN PLANTS Have you ever wondered how water reaches the top of tall trees Plants need to move molecules over very long distances, much more than animals do They also do not have a circulatory system in place. Water taken up by the roots has to reach all parts of the plant, up to the very tip of the growing stem. The photosynthates or food synthesised by the leaves have also to be moved to all parts including the root tips embedded deep inside the soil
TRANSLOCATION In a flowering plant the substances that would need to be transported are water, mineral nutrients, organic nutrients and plant growth regulators. Over small distances substances move by diffusion and by cytoplasmic streaming supplemented by active transport. Transport over longer distances proceeds through the vascular system (the xylem and the phloem) and is called translocation.
DIRECTION OF TRANSPORT In rooted plants, transport in xylem (of water and minerals) is essentially unidirectional, from roots to the stems. Organic and mineral nutrients however, undergo multidirectional transport. Hormones or plant growth regulators and other chemical stimuli are also transported in a strictly polarised or unidirectional manner
MEANS OF TRANSPORT -Diffusion Facilitated Diffusion Active Transport
DIFFUSION Movement by diffusion may be from one part of the cell to the other, or from cell to cell, or over short distances, say, from the intercellular spaces of the leaf to the outside. No energy expenditure takes place. In diffusion, molecules move in a random fashion, the net result being substances moving from regions of higher concentration to regions of lower concentration. Diffusion rates are affected by the gradient of concentration, the permeability of the membrane separating them, temperature and pressure
FACILITATED DIFFUSION The diffusion rate depends on the size of the substances; obviously smaller substances diffuse faster. The diffusion of any substance across a membrane also depends on its solubility in lipids, the major constituent of the membrane. Substances soluble in lipids diffuse through the membrane faster.