News Excerpt
A team of researchers at the Indian Institute of Science Education and Research (IISER), Bhopal, has conducted a study on seed germination that could have a major impact on agriculture in the long run by helping determine the optimum timing of seed germination and thus ensure high plant yields.

•    Abscisic acid (ABA) is one of the “classical” plant hormones, that regulates many aspects of plant growth and development.
•    It is a sesquiterpene, which has important roles in seed development and maturation, in the synthesis of proteins and compatible osmolytes, which enable plants to tolerate stresses due to environmental or biotic factors, and as a general inhibitor of growth and metabolic activities.
•    ABA is derived in higher plants from a C40 carotenoid, 9′-cis-neoxanthin, which is oxidatively cleaved to give xanthoxin (C15) and an apoaldehyde (C25).

    The work focused on the interplay between plant hormones like abscisic acid (ABA) which inhibit the sprouting of the seed and environmental cues like light (which promotes the sprouting process) and darkness.
    Although ABA, a ubiquitous plant hormone, was discovered almost 80 years ago, there is scant knowledge about the mechanisms controlled by ABA for arresting the post-germination growth in response to environmental cues.
    All plants, depending on their external environment, make the decision to open its embryonic leaves after sprouting or to enforce a growth arrest.
    Being ‘sessile’, plants have an extraordinary sensing mechanism to allow them assess environmental conditions before a seed decides to open up and establish as a young seedling.
    Like humans, plants, too, have hormones like ABA that modulate their growth and development.
    Just after sprouting, the young seed must take a crucial decision on whether to go ahead with the ‘seedling establishment’ process (the critical stage of plant growth) or not.
    The ‘right decision’ taken by the young seed ultimately allows it to secure its independence and take care of itself as it matures into an adult plant.
    Stress defence is analogous to the baby steps in humans before a child can stand on its own feet and walk. Making the right decision in the allocation of resources to growth or stress responses is critical for the successful establishment of seedlings.
    If seeds germinate in adverse environmental conditions, seedlings ultimately risk expediting precious energy in ‘stress defence’ rather than growth.
    Understanding the complex factors that modulate ABA sensitivity is vital to developing economically important plant varieties that have better tolerance to stress conditions.
    The results of the study, though in its elementary phase, are vital. Over the past two months, more than one lakh farmers in Maharashtra have lodged complaints against seed companies, prompting the State Agriculture department to lodge over 75 FIRs against seed companies for giving soybean seeds to farmers which failed to germinate.
    ‘The protein acts as a ‘master regulator’ of the seed’s growth by controlling several aspects of plant development, including seed dormancy and germination, as well as controlling growth under adverse conditions such as drought or salinity.
    COP1, which is a highly conserved protein (protein which undergoes fewer amino acid replacements), may play similar roles in different crop plants.
    COP1, which is more active in dark and less active in light, is responsible for this relatively higher ABA sensitivity in dark conditions.