Plant water Relation,Bsc Botany 6th semester note Under CBCS Dibrugarh University

 আজিৰ এই পষ্টটোত ,যেতিয়া উদ্ভিদ বিজ্ঞান বিভাগত পঢ়ি আছিলো আৰু তেতিয়া বনাইছিলো পৰীক্ষাৰ বাবে নোট সেয়ে এই পষ্টটোত  মোৰ নোটৰ কিছু কালাংশ DTP কৰি পষ্ট কৰি দিলো।ইয়াৰ কিছু সংখ্য ইন্টাৰনেটৰ সহায়ত বনোৱা হৈছে।বেছিকে BILOGY DiSCUSSION পৰা প্ৰস্তুত কৰিছিলো।ধন্যবাদেৰে পৰৱৰ্তী সময়ত আৰজ নতুন নোটসমুহ আপলোড কৰাৰ ব্যবস্থা কৰিম॥In today's post, when I was studying in the Department of Botany and then I made notes for the exam so I posted some excerpts of my note in this post by DTP. Some of these numbers have been made with the help of internet. Most of them were made from BILOGY DiSCUSSION. I will arrange to upload the new notes next time with thanks.

                 Plant water Relation

 

Transpiration:-Transpiration is the biological process by which water is lost in the from of water vapour from the cerial parts of the plants.

                   Like all living  organisms plants also require  an excretory system to discharge excess of elimination of excess wates from their body. This process of elimination of  excess water body  from plant body is known as ‘ transpiration.’  It generally  the evaporation of water from the surface of leaves.During  these process of transpiration ,water molecules in the plant tissues are removed from the aerial parts of the plant.Only small amount of the water absorbed by the plants is utilized in growth  and developedment .The rest is eliminated  in the from of transpiration.

Factors affecting the Rate of Transpiration:-

The factors affecting the rate of transpiration can be categorrised under two stub heads.

1.External or environmental factors.

External or environmental factors are include in there are-

(a)Humidity of the air.

(b)Temperature.

(c)Wind Velocity

(d)Light

(e) Atmospehere Pressure.

(f)Water Supply.

(g)Spray and Dust.

(h)Vital Activities.

2.Internal or structural Factors.

 

Internal or structural Factors in include there are

(a)Stomata frequency.

(b)Structural peculiarities of leaf.

 

 

 

Mechanism of Transpiration

 

The Mechanism of transpiration is completed in two stages :-

1.The diffusion  of water of mesophyl cells into intercellular spaces.

2.The diffusion of water vapours of inter cellular spaces into water dry atmospehere.

The roots of plants continuously absorb water and mineral salts from the soil  which ascend through the xyllemvessels and reach to the leaves .The mesophyll cells of leaves becomes turgid due to  excess amount of this absorbed water from mesophyll cells into intercellular spaces.The intercellular  spaces now become saturated with water and their water vapour pressure of atmospehere  .Stimulataneously DPD of Intercellular spaces is decreased much than the DPD of water vapour present in the atmosphere.Thus the water from the intercellular spaces diffuses into the atmospehere in the form of vapour through stomata ,lenticels..andcuticle.

      About  Ninty Percent of the absorbed water is transpired through stomata.The intercellular spaces of mesophyll cells remain always saturated with water vapoures.When the air of outer atmosphere is unsaturated the water diffuses from sub-stomatal chambers into  the  atmpsphere ,thus the process of transpiration.