Orthodox, Intermediate, and Recalcitrant Seed - Center for Plant Conservation (2024)

FAQs

What are orthodox and recalcitrant seeds? ›

Orthodox seeds are capable of being dried to internal seed moisture of less than 12% water, stored at freezing temperatures, and surviving. Recalcitrant seeds cannot be stored in a conventional freezer as they cannot survive after drying and/or freezing at -20°C.

Recalcitrant seeds are seeds that do not survive drying and freezing during ex-situ conservation. By and large, these seeds cannot resist the effects of drying or temperatures less than 10 °C (50 °F); thus, they cannot be stored for long periods like orthodox seeds because they can lose their viability.

After developing seeds reach physiological maturity, they either proceed to desiccate (orthodox seeds), germinate on the plant (vivipary), or bypass complete desiccation (recalcitrant seeds). Recalcitrant seeds lose viability after drying.

Because they are shed at a range of species-related high water contents and will not tolerate dehydration to levels appropriate for low RH/sub-zero temperature storage, recalcitrant seeds cannot be conserved using standard genebank approaches.

Examples of intermediate seed are Azadirachta indica, Maesopsis eminii, Dovyalis caffra and Artocarpus heterophyllus. Orthodox seed is commonly dried under direct sunlight for 2-3 days to a moisture content of 5-8%.

Recalcitrant seeds refer to seeds that will not be stored by freezing or drying. Recalcitrant seeds typically germinate and establish quickly because they cannot tolerate desiccation. Plants that produce recalcitrant seeds include avocado, coffee, mango, lychee, cocoa, and rubber tree.

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.

Orthodox seeds are seeds which will survive drying and/or freezing during ex-situ conservation, as opposed to recalcitrant seeds, which will not.

Recalcitrant. Seeds which cannot survive drying below a relatively high moisture content (often in the range 20–50% wet basis) and which cannot be successfully stored for long periods.

What are the 4 types of seeds? ›

The below mentioned article highlights the four important types of seed. They are as follows: (1) Dicotyledonous Exalbuminous Seeds (2) Dicotyledonous Albuminous Seeds (3) Monocotyledonous Albuminous Seeds and (4) Monocotyledonous Exalbuminous Seeds.

Papaya seeds have been grouped as recalcitrant seed by Chin et al. (1984) and Hofmann and Steiner (1989) but more recently it was grouped as the intermediate seed (Ellis et al., 1990). Papaya seed has survive for a short period of time under the ambient conditions.

Local examples of recalcitrant seeds are oaks, walnuts, and maples—they germinate immediately with no dormancy. Many tropical rainforest plants also are recalcitrant, never going into true dormancy.

The only means for long-term conservation of the germplasm of recalcitrant-seeded species is by cryopreservation in liquid nitrogen (LN), which is not possible for intact seeds.

Essential principles govern the storage of seeds, in particular practices relating to the control of tempera- ture and relative humidity (RH) in the storage facility itself. Seed with a lower moisture content (MC) kept at lower temperatures can be stored for longer before the quality deteriorates.

The seed plants are often divided arbitrarily into two groups: the gymnosperms and the angiosperms.

Orthodox – the seeds able to tolerate moisture loss and less seed moisture favours the storage. i.e. decreased moisture increased storage period. Eg. Rice, sorghum , and most of the cultivated species.

The two major types of seed plants are the gymnosperms (seeds in cones) and angiosperms (seeds in ovaries of flowers). Figure below shows how the seeds of gymnosperms and angiosperms differ.

Recalcitrance is the inability of plant cells, tissues and organs to. respond to tissue culture.

Cryopreservation involves storage at ultralow temperature, often in liquid nitrogen (−196°C) (7–9). Rapidly advancing methods can be used to essentially stop water from freezing within recalcitrant seed cells and obviate lethal freezing damage (3, 7–9).

What are the two types of Orthodox? ›

Globally, there are 15 self-governing churches among the Eastern Orthodox, while the Oriental Orthodox, including the Copts, Armenians, Ethiopians and Assyrians, have their own churches. Most of the denominations in both groups have institutional churches in the U.S., with the Greek Orthodox Church being the largest.

Example Sentences

Adjective He took an orthodox approach to the problem. She believes in the benefits of both orthodox medicine and alternative medicine. He is a very orthodox Muslim. I attend an Eastern Orthodox church. My grandmother is Russian Orthodox.

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.

Orthodox beliefs, methods, or systems are ones which are accepted or used by most people.

4.4.

Rice produces orthodox seeds, which can be dried and stored at low temperatures to prolong viability.

Two kinds of plants bear seeds: gymnosperms and angiosperms. ​Gymnosperm​ means "naked seed," and refers to the fact that these seed-bearing plants do not produce fruit to protect their seeds. In contrast, the ​angiosperms​ – otherwise known as the "flowering plants" – form flowers that become fruit.

Extraction methods include solvent extraction, distillation method, pressing and sublimation according to the extraction principle. Solvent extraction is the most widely used method.

There are two types of extraction, liquid-liquid extraction also known as solvent extraction as well as solid-liquid extraction. Both extraction types are based on the same principle, the separation of compounds, based on their relative solubilities in two different immiscible liquids or solid matter compound.

The most common methods are wind, water, animals, explosion and fire. Dandelion seeds float away in the wind.

Recalcitrant and orthodox seeds differ greatly in their ecology and morphology. Recalcitrant seeds are primarily from perennial trees in the moist tropics. In some cases, they also come from temperate tree or aquatic species, while most orthodox seeds are from annual species grown in open fields.

What does recalcitrant mean in biology? ›

Biology definition:

Being recalcitrant is defined as a distinguished ability to resist change in some property. The term is used to describe the inability of a seed to germinate in plant seed biology or the inability of a plant cell or tissue to respond to tissue culture manipulation in plant tissue cultures.

"There are three parts of a seed." "A bean or seed consists of a seed coat, an embryo, and a cotyledon." "The embryo is the tiny plant protected by the seed coat."

Recalcitrant includes large seeds, such as Mango, Avocado, Cocoa, Lychee, Jackfruit, etc.

Citrus seeds have also been reported to possess recalcitrant storage behavior (King and Roberts, 1980). It has been shown that seeds of several species can survive considerable desiccation, but, nevertheless, do not show strictly orthodox seed storage behavior (Ellis et al., 1990; Hong and Ellis, 1990).

Seed Collection and Storage

Growing sugar apple from seed can be challenging even if you live in a suitable climate, because of the plant's quirks. It has what botanists like those at the University of Hawaii call ​recalcitrant​ seeds, meaning they don't store well and are unlikely to remain viable if you let them dry.

Seeds are conserved for > 50 years without any loss of viability (Usberti and Gomes, 1998). In ex-situ conservation of seeds, seeds can be stored as active (medium term) and base (long term) collections.

There are basically two methods used in forest genetic resource conservation, namely the in situ (on site) and the ex situ (off site) conservation methods. The in situ conservation method is the protection and maintenance of species populations in the ecosystem in which they occur.

Germplasm conservation is the most successful method to conserve the genetic traits of endangered and commercially valuable species. Germplasm is a live information source for all the genes present in the respective plant, which can be conserved for long periods and regenerated whenever it is required in the future.

What are the different methods of seed storage? ›

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).

Seed in the combine, grain wagon, and bulk storage or drying bins are in storage and their quality is affected by the same factors that affect the quality of seed during the packaged seed segment of the storage period.

Moisture, temperature, and the proportion of oxygen are key environmental factors that affect seed deterioration and loss of viability.

Orthodox seeds are seeds which will survive drying and/or freezing during ex-situ conservation, as opposed to recalcitrant seeds, which will not.

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.

Orthodox. Seeds which can be dried down to a low MC of around 5% (wet basis) and successfully stored at low or sub-freezing temperatures for long periods.

Globally, there are 15 self-governing churches among the Eastern Orthodox, while the Oriental Orthodox, including the Copts, Armenians, Ethiopians and Assyrians, have their own churches. Most of the denominations in both groups have institutional churches in the U.S., with the Greek Orthodox Church being the largest.

adjective. Orthodox beliefs, methods, or systems are ones which are accepted or used by most people.

: conforming to established doctrine especially in religion.

Cryopreservation is the only option for long-term conservation of the germplasm of recalcitrant-seeded species, which necessitates excision of explants, ideally embryonic axes, that can be dehydrated sufficiently rapidly to limit metabolism-linked damage.

Is rice an orthodox seed? ›

4.4.

Rice produces orthodox seeds, which can be dried and stored at low temperatures to prolong viability.