Droplets of salt water with heat wave caused the scorching of the plants along the west coast of India

Print

     Droplets of salt water with heat wave caused the scorching of the plants along the west coast of India

Scorching of leaves in most of the fruit trees, vegetables, coconut and other trees were noticed during the 3rd and 4th week of June along the west coast of India, especially in Kerala and Karnataka.   Ruling out the acid rain, wind fire or ‘heat burst, Scientists of the CPCRI has identified the cause of the leaf scorch due to accumulation of high salt on the leaves.   It is a natural phenomenon, every year the commencement of monsoon starts with gusty winds and heavy rains in the month of June.  However, this year it was unusual with wind speed of 30-40 km/hr with accompanying little rain (660mm in the month of June) as compared to the corresponding period wind speed of 22-25 km/hr with heavy rains (960 mm) of last year (2014). In the dry weather the salt from the ocean evaporates as tiny droplets and the gusty wind carries it to a long distance on the sea shore and adjoining areas. Salt deposit on the leaves was seen in those plants which are growing few meters from the sea shore all along the west-coast.   Due to lack of sufficient amount of rainfall, leaves do not have an opportunity to shed the salt before it begins to affect the tissue causing browning, burning and eventually necrosis (cell or tissue death).

Ions like sodium (Na) and Chlorine (Cl) are highly injurious to plants which are predominantly present in sea water. These ions enter the leaves and causes osmotic imbalance which not only dehydrates the tissue but also affect the process of photosynthesis, protein synthesis, etc. The salt concentration in the ocean is very high to the tune of 54 dS/m.    Generally annual crops like cereals, pulses, oil seeds tolerate salt in the range of 2-4 dS/m while fruit trees can tolerate 4-6 dS/m.  Coconut is a moderately salt tolerant crop and can withstand salinity up to 8 dS/m. Similar is the case with guava, pineapple, cashew, sapota, arecanut while banana, papaya, lime, mango are sensitive to salt. Trees like Casuarina have better excretion mechanism to salt and hardly any damage is seen. 

The degree of scorching and necrosis depends on the salt concentration. The leaf necrosis was more in plants growing near the sea shore and declined gradually away from it.  In some trees and shrubs necrosis is seen on the windward side only while the other side is green in colour.  Plants with complete necrosis may die within few days, while with few green leaves it may recover back slowly. 

             It is a natural calamity and its effect could be mitigated to a large extent by planting salt tolerant wind barriers like Casuarina as a border plant near the sea shore. These plants have evolved specialized mechanism by which they exclude or compartmentalize the salt in the cell and thereby minimize the salt effect on organelles and make the plant tolerant.   The wind carrying salt will be deposited on these plants and the main crop will be protected.   Also the salt effect can be minimized by soil amendments like application of organic manure, fresh water spray to the young seedlings to wash off the salts etc.  The leaf analysis of healthy and damaged plants is in progress to quantify the salt concentration and to study the mechanism of salt tolerance across the species.  

                 

                            

 

  



ICAR-Central Plantation Crops Research Institute
Kudlu.P.O,
Kasaragod,Kerala, 671124


Phone : 04994-232894
Fax : 04994-232322
E-Mail :This email address is being protected from spambots. You need JavaScript enabled to view it. ,
This email address is being protected from spambots. You need JavaScript enabled to view it. ,
This email address is being protected from spambots. You need JavaScript enabled to view it.

2612362
Time: 2017-10-23 15:14:50

                   

Copyright © 2014 CPCRI. All Rights Reserved