Germination

First the young root appears.	The skin splits and the shoot straightens, pulling the cotyledons with it.	The main root gets bigger and grows side roots, and the first leaves appear.

Germination happens when a baby plant is growing. The plant is between thecotyledons. This is a seed. The seed is underground and is collecting nutrients. When a seed starts to grow, we say it germinates. The cotyledons store food for the baby plant inside the seed. When the seed starts to germinate, the first thing to come out is the main root. The skin starts to split and the tiny shoot straightens, carrying the cotyledon[s] with it. The main root gets bigger. Side roots appear and so do leaves. To grow, the seed's growing conditions usually have to be damp, warm, and dark, like springtime soil. A dry seed will stay dormant unless it soaks in some water. Then it will start to germinate. source : http://library.thinkquest.org/3715/

How Plants Grow

Root hairs are cells. They take water to the main root. Then the main root brings the water to the main plant. The roots also help hold the plant in the ground. The inside of a root has four different parts. The epidermis is the outside part. It is like our skin. It protects the inside parts of the root. Plants take in water from the soil through their roots. The water passes through the vascular raysuntil it reaches the center of the root, the stele. This is where the veins are located. The veins are called xylem. They carry the water and food through the plant. Between the epidermis and the stele is the fleshy cortex. source : http://library.thinkquest.org/3715/

Photosynthesis

Animals inhale oxygen and exhale carbon dioxide. Green plants are the only plants that produce oxygen and make food, which is calledphotosynthesis. Photosynthesis means ''putting together with light.'' This takes place in chloroplasts, which have chlorophyll in them. Chlorophyll absorbs the sunlight. From sunlight, green plants combine carbon dioxide and water to make sugar and oxygen. Green plants use sugar to make starch, fats, and proteins. There are tiny pores called stomota. Carbon dioxide and oxygen enter and leave through the stomatarespectively. source : http://library.thinkquest.org/3715/

Spreading Seeds

A seed has everything it needs to produce new plants. No seed can grow with the fruit around it. A seed has to have enough water, good soil, and sunlight. Sometimes people plant them and other times the seeds get planted on their own. People also put seeds in gardens or fields, and water and fertilize the seeds.
Birds help some fruits like the cherry by eating the fruit around the seed. The mistletoe's seeds are covered with a sticky substance that sticks to the bird that tries to eat it. The mistletoe's seeds have to land on the tree or they die.
Some seeds travel by sailing in the wind. Others float in the water to get to the land. Others hitchike on animals. Some just get blown in the wind. Seeds can also grow in a flower and drop to the ground. When the seed leaves the flower or whatever it was in, it's called dissemination. This is one of the most important steps in the seed's life. Some tree seeds drop directly below the parent and die because there is not enough light or food for them to grow.
The seeds that travel by wind must be light-weight. Some of these seeds have wings, like the maple seed. Some of these seeds have gone 32 miles on a windy day. Another flying seed is the dandelion which gets planted because ants carry the seeds down into thier hole.
The water travelers float away from their parent trees. Coconuts may drift for several months and travel for up to 1,200 miles (2,000 km) before reaching dry land. The coconuts are able to float because of special fibers around their seeds.
The hitchhikers are built with spikes. They get stuck to animals and eventually fall off. Some seeds have a sticky substance that makes them stick to animals. Then they travel to another place to grow.
Some plants have sacks that explode. The squirting cucumber bursts open and shoot its seeds up to 27 feet (8m) away from the parent plant. The seeds zoom off and may travel as fast as 62 miles (100km) per hour.

source : http://library.thinkquest.org/3715/

Flower

	What Is A Flower?
	All plants produce flowers for the same reason: to make seeds so another plant can grow.

A flower is the part of the plant that makes the seeds. The main parts of a flower are the carpels and stamens. These parts are often found in the center of the flower. There are egg cells in the carpel and pollen cells in the stamen. All flowers have four basic parts:sepals, petals, carpels andstamen. Different flowers have different numbers and shapes of these parts. source : http://library.thinkquest.org/3715/

Seeds

A Bean Seed is a Dicot.

Dicots are seeds that have two parts, such as a bean seed. A bean seed that has soaked in water for a day or two has a soft outside covering. This is the seed coat. The seed coat would probably slip off the seed easily. The bean seed has a slit going down the middle of the seed. Inside is a tiny plant called an embryo. The two large parts of the seeds are called cotyledons. They supply the food for the young plant when it's growing. The bean seed has two parts. Therefore, it is a dicotyledon, or dicot for short.

A Corn Seed is a Monocot.

Monocots are seeds that only have one cotyledon, such as the corn seed. The corn seed does have a seed coat, but it does not slip off as easily as the bean seed. The corn seed will not split like the bean seed. It stays in one piece. One cotyledon surrounds the embryo. It is a lighter color than the rest of the seed and is called the endosperm. It provides food for the growing plant. The corn seed is a monocotyledon, or monocot. ''Mono'' comes from the Greek word monos, meaning ''one''. source :  http://library.thinkquest.org/3715/

Lima kumpulan tumbuhan berdasarkan jangka hayat

Tumbuhan efemeral

Tumbuhan efemeral mempunyai jangka hayat yang sekejap dan selalunya mempunyai dua kitar hidup dalam satu musim. Setiap generasi mati selepas melepaskan biji benih, maka generasi seterusnya terhasil melalui biji benih sahaja. Contoh yang paling banyak digunakan ialah rumpai gransel (Senecio vulgaris) dan arabidopsis (Arabidopsis thaliana). Kerana tempoh hidup ia yang singkat, istilah 'efemeral' juga diberikan untuk tumbuhan gurun saka yang berbunga sepintas lalu selepas hujan.

Tumbuhan semusim

Tumbuhan semusim ialah tumbuhan yang biasanya mati selepas melengkapkan kitaran biologinya bermula dengan percambahan dan diakhiri dengan berbunga atau penghasilan biji benih. Ini berlaku dalam tempoh masa setahun atau semusim . Bagi tumbuhan semusim benar hanya akan hidup lebih dari setahun jika mereka dihalang dari menghasilkan biji benih. Sesetengah tumbuhan tak berbiji juga boleh dianggap semusim walaupun mereka tak mengeluarkan bunga jika ia mati dalam tempoh masa setahun atau semusim.

Antara contoh tumbuhan semusim banyak terdapat pada sayur-sayuran berbanding pokok buah-buahan.

Tumbuhan dwimusim

Tumbuhan dwimusim ialah tumbuhan yang mengambil masa dua tahun (iaitu, dua musim pertumbuhan) untuk melengkapkan kitar hidupnya.^[1] Pada tahun pertama, ia tumbuh daun, batang, dan akar (struktur tampang). Kemudian ia masuk tempoh kedormanan pada musim sejuk. Selalunya batang kekal pendek dan daun dekat dengan tanah, membentuk roset. Banyak tumbuhan dwimusim memerlukan rawatan sejuk, atau pemvernalan sebelum ia berbunga. Pada tahun seterusnya, iaitu pada musim bunga atau musim panas, batang ia akan mula tumbuh dengan cepat untuk fasa pembiakan pula. Kemudian ia berbunga, menghasilkan buah dan benih dan akhirnya ia mati. Kebanyakkan tumbuhan dwimusim berasal dari kawasan beriklim sederhana.
Dari perspektif pekebun, status tumbuhan sebagai semusim, dwimusim, atau saka berbeza mengikut tempat dan tujuan. Tumbuhan dwimusim untuk tanaman bunga, buah, atau benih ditanam dalam tempoh kitaran ia hidup selama dua tahun. Manakala tumbuhan dwimusim untuk tanaman makanan seperti sayuran atau akar pula ditanam sebagai tanaman semusim (kurang dari setahun). Tumbuhan dwimusim tulen hanya berbunga sekali dalam hidupnya, berbeza dengan tumbuhan saka yang berbunga setiap tahun setelah matang.
Contoh tumbuhan dwimusim ialah pasli, lobak, bunga balung ayam dan lili. Ahli pembiak baka tumbuhan telah menghasilkan kultivar semusim dari tumbuhan dwimusim yang akan berbunga pada tahun pertaman dari biji benih seperti pokok sarung tangan musang dan pokok stok.

Tumbuhan saka

Tumbuhan saka ialah tumbuhan yang hidup lebih dari dua tahun.^[1] Istilah ini digunakan bagi membezakan antara tumbuhan yang hidup semusim dan dwimusim. Kadang-kala istilah ini disalah anggap oleh sesetengah pekebun atau ahli hortikultur merujuk sebagai khusus kepada tumbuhan herba saka. Untuk lebih tepat, tumbuhan berkayu seperti pokok renek dan pokok juga merupakan tumbuhan saka.

Bagi negara beriklim sederhana, pertumbuhan pokok saka berlaku pada musim bunga dan musim panas. Kemudian ia akan meluruhkan dedaunnya pada musim luruh bersedia untuk ke musim sejuk. Pada masa ini ia kekal dorman. Ia kemudian tumbuh kembali pada musim bunga dan kitaran ini berlaku setiap tahun. Ini berlainan dengan pokok saka di kawasan beriklim tropika yang mana ia kekal hidup sepanjang tahun tanpa meluruhkan dedaun.

 Daripada Wikipedia, ensiklopedia bebas.