Ngā kākano ❘ Seeds

Kua ruia atu te kākano – kātahi ka aha?

Mēnā ka tau te kākano ki tētahi wāhi arotau, ka tinaku, ā, ka pihi he tipu hou.

E uhia ana te kākano e te kahukano.

Kei roto i te kākano te kikiri (te punua tipu) me tōna pātaka kai.

Ka uruuru mai te wai me te hāora ki te kākano, ka whakamahana ngā hihi o Tama-nui-te rā i te oneone, nāwai, nāwai, ā, ka pihi mai te punua pakiaka me te wana.

The seed has been sown – what next?

If the seed lands in a favourable spot, it will germinate and the new plant will sprout.

The seed coat covers the outside of the seed.

Inside the seed are the embryo and food stores.

Water and oxygen enter the seed through the micropyle, the Sun heats the soil, then the embryonic shoot and root sprout from the seed.

He aha ngā momo tupu e whai ai i ngā kākano?

He rerekē te tikanga a tēnā momo tupu, a tēnā momo tupu e whai ai i ngā kākano, mō te taha ki te whakaputu kai mā te tupu hou. Waihoki, he rerekē te putanga o te tupu hou a tēnā momo, a tēnā momo i te tinakutanga.

What are the different types of seed-producing plants?

The different types of seed producing plants each store food for the new plant in a different way. They also differ in how the new plant emerges from the seed during germination.

Te tinakutanga o ngā kākano: te tipu pātaka-rua

Ko tā ngā pātaka, koirā ngā pātaka matua o roto i ngā tupu pātaka-rua. He wāhanga ērā pātaka o te kikiri, nō reira, e rua ngā huinga o ngā pūira tō ia pātaka - tētahi nō te tupu whaea, ā, tetahi nō te tupu matua.

I ngētehi wā ka tipu ngā pātaka hei rau tuatahi o te tupu hou, ā, ka pihi ake ki runga ake i te oneone i te tinakutanga. Heoi, mō ētahi atu momo, pērā i ngā pī, ka noho kei raro kē i te oneone.

Germination of dicotyledon seeds

The cotyledons are the main food store in dicotyledons. The cotyledons form part of the embryo. Therefore, they have two copies of each chromosome – one from the mother plant and one from the father.

They sometimes act as the first leaves of the new plant and often sprout above ground during germination. However, in some species (such as peas), they stay below ground.

Te tinakutanga o ngā kākano: tipu pātaka-moke

Ko te ‘endosperm’ te pātaka matua kei roto i ngā kākano pātaka-moke. He pūtautau te ‘endosperm’ e whakaahuatia ana i te whakatōnga. Kei a ia ngā huinga e toru o ia pūira – e rua nō te tupu whaea, ā, kotahi nō te tupu matua.

Ko te mahi matua o te pātaka kei ngā kākano pātaka-moke, ko te whakawhiti i ngā kai mai te “endosperm” ki te wana me te punua pakiaka. Kāore te pātaka i te pihi ake te kākano. Engari anō te wana, ka pihi kē mai i te kākano kei roto i tētehi kahukano.

Germination of monocotyledon seeds

In monocotyledons, the single cotyledon absorbs resources from the endosperm and transfers them to the new shoot and root. The cotyledon does not sprout from the seed. The new shoot emerges from the seed within a protective shield called the coleoptile.

The endosperm is the primary food storage organ in most monocotyledons. The endosperm is a tissue formed during fertilisation. It has three copies of each chromosome – two from the mother plant and one from the father plant.

Te tinakutanga o ngā kākano: rākau koroī

He aha te rerekētanga o ngā kākano koroī i ngā kākano o ngētehi atu momo tupu?

Ko te ‘gametophyte’ te pātaka matua o ngā kākano koroī. Ko tā te ‘gametophyte’ he whakaputa i te pūtau hema-uwha, ā, kei a ia kotahi huinga anake o ngā pūira o te tupu whaea.

Ko te mahi matua o ngā pātaka o te kākano koroi, hei rau tuatahi mō te tupu hou. Neke atu i te 20 ngā pātaka kei roto i ngā kākano o ngētehi momo rākau koroī. Te nuinga o te wā, ka pihi ai aua pātaka ki runga ake i te oneone.

Germination of conifer seeds

What is the difference between conifer seeds and those of other plants?

The main food storage organ in conifer seeds is the gametophyte. This is the structure that produces the egg cell and contains a single copy of the mother plant’s chromosomes.

The main function of cotyledons in most conifers is as the first leaves of the new plant. Some conifer species have more than 20 cotyledons within their seeds. Conifer seeds usually sprout these above ground during germination.

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