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Plant Physiology Program

Plant Physiology Program
NARC, Islamabad

INTRODUCTION

The rationale of this programme is that the plant physiological studies be directed both at understanding the nature of stress responses, possible methods of combating them and most importantly understanding the basis of the genetic variation in stress resistance providing firm guidelines to the breeders for the selection of resistant lines. This programme aims specifically to investigate the neglected areas so compensating for an imbalance in existing research and hopefully contributing to the overall aim of introducing better stress adapted wheat, rice and other crops for Pakistani conditions. In Pakistan there is a great need of integration among basic research, whole plant response studies and field testing especially related to physical stresses to decrease the difference between potential yield and actual yield of major crops of the country.

The program seeks to address the fundamental physiological& biochemical issues associated with poor grain formation and grain fill in selected crops under environmental stresses like drought, salinity, and heat etc to enhance the reproductive yield.

FACILITIES

Two-labs; One-well equipped Lab. for plant bio-chemical analysis,

and Second lab for plant growth equipped with growth chambers, agronomic data collection.

SERVICES

Provide laboratory research facilities/training to researchers/students regarding latest physiological and biochemical techniques to undertake high-tech physiological research.

CURRENT RESEARCH

  • Evaluation of Wheat Synthetics / Advance lines for Abiotic Stresses.
  • Salinity tolerance ranking of wheat synthetics based on physiological and biochemical parameters.
  • Heat tolerance evaluation of wheat (Triticum aestivum L.) genotypes for post anthesis temperature stress.
  • Identification of genotypic variation in phosphorous use efficiency of wheat grown on phosphorous deficient calcareous soils

ACHIEVEMENTS

Salinity tolerance ranking of wheat genotypes

Fifty wheat genotypes including advanced line and synthetic hexaploid developed by NARC, wheat program and wheat wide crosses were evaluated in hydroponics culture for salinity tolerance.

  • Based on physiological parameters like K+: Na+, chlorophyll contents and shoot dry weight, Calfia, LU-26s, S-24, Shorawaki, Chinese spring, Galvez, Kharchia, NR-372 and SH-13 were found the most salt tolerant.

Phytohormones induced drought mitigation in wheat and rice

Wheat: A pot experiment was conducted in glasshouse to test the hypothesis that seed soaking with abscisic acid (ABA) and salicylic acid (SA) improves the drought tolerance of wheat. Four wheat varieties viz Chakwal-97, Wafaq-2001, GA-2002 and Punjab-96 were pre-soaked in aqueous solutions of ABA, SA and distilled water treated as control. Drought stress was imposed at tillering and pre-anthesis growth stages.

  • Drought stress decreased the grain yield and more when it was imposed at pre-anthesis growth stage. Chakwal-97 and Wafaq-2001 performed better and Punjab-96 was found sensitive towards drought stress. Both the hormone pre-treatments increased the grain yield of wheat verities under drought stress. The increase was greater with ABA than SA seed treatment. Highest increase in grain yield was recorded by ABA in Chakwal-97 (20%) followed by Punjab-96 and GA-2002.
  • Drought stress decreased chlorophyll contents in wheat leaves; however, ABA & SA pre-treatment significantly increased the chlorophyll contents. ABA & SA increased (20%) soluble proteins and sugar in all the tested wheat varieties under drought stress. Both hormones treatment enhanced the proline content in all the tested varieties. The increase was highest in GA-2002, followed by Punjab-96 with ABA treatment. ABA improved the leaf relative water content by 9% and SA by 6%. Drought stress increased the activity of antioxidant enzyme; supperoxide dismutase (SOD) by 50%. Both the hormones enhanced the SOD activity. The increase was 18% with SA and 15% with ABA. Cell membrane stability was improved (8%) by salicylic acid pre-treatment under drought stress.

Rice: A study was conducted in glasshouse to ameliorate the seed sterility in rice under drought stress. Plants of rice varieties viz. Basmati-385 and KS-282 were sprayed with Glycinebetain and growth regulator (Kinetin) at pre-anthesis growth stage just before drought application.

  • Under drought stress, Glycinebetaine and Kinetin increased 18-20% paddy yield of Basmati-385 and 19-29 % of KS-282. The increase was probably due to increased number of filled seeds per plant. The increase in paddy yield was greater with Kinetin (20-29%) as compared to Glycinebetaine (18-19%).
  • The treatments enhanced the translocation of photosynthates (sugar, carbohydrates, starch) from the source (leaves) to sink (seed). Both treatments increased the supperoxide dismutase activity, which protect the enzymes involved in translocation of photosynthates from source to sink under drought.

Physiological assessment of wheat genotypes for drought tolerance

Fifteen wheat genotypes viz Sehar-2006, EBWYT-514, Sariab-92, Zarlashta-99, NR-356, NR-358, NR-360, NR-366, NR-367, NR-368, NR-371, NR-372, NR-375, NR-377 and one cultivated variety GA-2002 used as check were exposed to three consecutive drought stresses cycles at tillering, pre-anthesis and milky growth stages.

  • Significant reduction in grain yield was observed in all the test varieties when drought was imposed at any growth stage. Drought stress significantly reduced the grain yield and its components like spikes per plant, spikelets and florets, seeds per spike in all the test varieties when drought was imposed at any growth stage. The reduction was greater at pre-flowering (44%) as compared to tillering and milky (31%) growth stages. The relative reduction in grain yield under drought stress was less in Zarlashta-99 (19%), NR-268 (26%), and NR-267(28%). Under drought stress, the total grain yield of Sehar-2006 and EBWYT-514 was at par with that of Zarlashta-99, NR-268 and NR-267 because of their high yield potential. Under drought stress, the overall performance of Zarlashta-99, NR-267 and NR-268 was better than other test cultivars. The same varieties produced higher grain under stress condition. The sterile florets were less in Zarlashta-99, NR-267 & NR-268 when drought was applied at tillering or pre- flowering growth stages.
  • Under water stress proline contents were significantly increased in all the wheat varieties. Highest proline accumulation was observed in NR-267, NR-268 and EBWYT-514 when drought was applied at tillering growth stages. Also, the same varieties had greater soluble proteins than the other test varieties. Membrane stability index test (MSI) measures the percent injury of leaf tissues under water stress and can be used for screening for drought stress. The MSI was highest of Zarlashta-99 (29%) followed by NR-267 and NR-268. Punjab-96 and Sehar-2006 being drought sensitive accumulated less proline & protein content as compared to control. The same variety showed lowest membrane stability index. Drought stress increased the activity of antioxidant enzyme; supperoxide dismutase (SOD). Greater SOD activity was recorded in Zarlashta-99 and NR-268. Based on the agronomic and physiological parameters the wheat varieties; Zarlashta-99, NR-267 and NR-268 were found drought tolerant whereas Punjab-96 a drought sensitive.

 

PUBLICATION

SCIENTIFIC STAFF 

S.No.

Name

Designation / Specialization

E-mail

       

01.

Dr. Jalal ud Din

PSO/ Program Leader

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02.

Dr. Noor Elahi Jan

SSO

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Resource Person:

Dr. Jalal-ud-Din, PSO/ Program Leader   This email address is being protected from spambots. You need JavaScript enabled to view it.

 

PARC Toll Free
Help Desk (8:00am to 4:00pm)

  +92-51-0800-84420

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