Intermediate seeds are characterized by at least one of the following symptoms: Longevity is highest if seeds are dried to between 45 and 65% RH compared to the 15 to 20% RH optimum observed for orthodox seeds. Seeds age faster when stored at conventional freezer temperatures compared to refrigerated temperatures.
What are the different stages of seed storage?
The storage period can thus be effectively divided into stages: • pre-harvest; • harvesting–warehouse; • warehouse; and • warehouse–planting. Following this logical sequence is essential from the outset to ensure that seed of the highest possible initial quality and safe moisture content is placed in warehouse storage.
What are the difference between orthodox and recalcitrant?
Orthodox seeds are the seeds that will survive during drying and freezing in ex situ conservation. In contrast, recalcitrant seeds are the seeds that will not survive during drying and freezing in ex situ conservation. So, this is the key difference between orthodox and recalcitrant seeds.
What is orthodox seed with example?
Orthodox seeds include for example, Citrus aurantifolia, Capsicum annum, Hamelia patens, Lantana camera, guava (Psidium guajava), Cashew (Anacardium occidentale) and most grains and legume types.
What is the importance of knowing which seed belongs to the 2 classifications?
Knowledge of seed structure can help in understanding how seeds respond during harvesting, conditioning, germination, and seedling emergence. Seed can be divided into two major classifications, monocots (monocotyledons) and dicots (dicotyledons), based on the number of cotyledons (seed leaves) in a seed.
What is the storage of seeds?
For good seed storage, always use sealed containers. After seed has been dried properly, store it in tin cans, metal boxes, glass jars, or plastic bags or container with lids that can be sealed (Figure 25).
What are the stages and general principles of seed storage?
c) Proper sanitation in seed stores. d) Before placing seeds into storage they should be dried to safe moisture limits, appropriate for the storage system. e) Storing of high quality seed only, i.e well cleaned , treated as well as of high germination with vigour and good pre-storage history.
What is orthodox seed?
Orthodox seeds are seeds which will survive drying and/or freezing during ex-situ conservation, as opposed to recalcitrant seeds, which will not. Thus some seeds are considered intermediate in their storage capability while others are fully orthodox.
What is the difference between recalcitrant seeds and orthodox seeds?
In recalcitrant seeds the safe minimum levels of oxygen, moisture content and temperature, and hence of respiration, are all considerably higher than those for orthodox seeds but, provided levels are maintained above the safe minima for each species, it appears that longevity can be extended by keeping them as close to …
Which is orthodox type of seed?
Orthodox seeds are seeds which will survive drying and/or freezing during ex-situ conservation, as opposed to recalcitrant seeds, which will not.
How are seeds stored in seed banks?
The most widely used technique for conserving plant genetic resources is seed banking. Seeds are dried to low moisture content and stored at subzero temperatures in cold stores or deep freezers. Many species have seeds that cannot survive under such conditions.
What is medium-term seed storage?
Medium-term storage under well-defined storage conditions is possible for species which show ‘intermediate’ seed storage behaviour. Such storage underwrites in situconservation activities against the threats of epidemics, fire, human pressures, etc. and against similar losses at field genebanks. It also facilitates utilization.
Why is classification of seed storage behaviour important?
Classification of seed storage behaviour is an essential step in devising a suitable method of conservation for each species. This is because long-term seed storage for genetic conservation under the conditions recommended by IPGRI (formerly IBPGR) is possible for species which show ‘orthodox’ seed storage behaviour.
What is the difference between intermediate seeds and recalcitrants?
Intermediate seeds are more tolerant of desiccation than recalcitrants, though that tolerance is much more limited than is the case with orthodox seeds, and they generally lose viability more rapidly at low temperature.
Is long-term seed storage for genetic conservation possible?
This is because long-term seed storage for genetic conservation under the conditions recommended by IPGRI (formerly IBPGR) is possible for species which show ‘orthodox’ seed storage behaviour. Medium-term storage under well-defined storage conditions is possible for species which show ‘intermediate’ seed storage behaviour.
