Biology: Sexual Reproduction of Plants (Chp 1.3)

C. Sexual Reproduction

C.1 Parts by Jennifer Angelina

flower parts

C.2  Process of Pollination

Serbuk sari yang menempel di kepala putik tumbuh membentuk pembuluh/tabung serbuk sari. Pembuluh serbuk itu tumbuh di dalam tangkai kepala putik, menuju ke bakal buahyang mengandung bakal biji. Di dalam pembuluh serubk sari, terdapat dua inti generatif dan satu inti vegetatif. Satu inti vegetatif mengatur pertumbuhan pembuluh serbuk sari, dan inti genratif membelah menjadi inti sperma pertama dan kedua.

Di dalam kandung lembaga (ovum/bakal buah) terdapat int sel telur dan inti kandung lembaga sekunder. Inti sperma pertama masuk melallui mikropil menuju ke inti sel telur dan melebur. Inti sperma kedua melebur dengan inti kandung lembaga sekunder yang nantinya akan membentuk endosperma yaitu cadangan makanan untuk calon tumbuhan baru.

C.3 Types of Pollinated Flower

Complete flower: 4 main parts: sepal, petal, stamen, pistil

Incomplete: < 4

Both sex organ: bisexual, hermaphrodite, perfect, bunga sempurna

1 sex organ: unisexual, imperfect,, bunga tidak sempurna

monoecious: posses both sex type flower, berumah 1

dioecious: posess only 1 sex type of flower, berumah 2

Wind Pollinated Flower

Insect Pollinated Flower

Dull, o need scent, no nectary guides no nectary glands Colourful, have odor have scent, nectaary guide
Dull petal, smaller, pendulous and fleoxible stamen and filament that protudes out, feathery stigma Big size for landing, bright and colourful petals
Pollen grains have smooth surface, light, large number Rough, large pollen, heavier, smaller number


Self Pollination (p. sendiri/tetangga)

Cross PollinatioN (p. silang)

Travel of polen grains in same flower/same plant Travel of pollen grain from one plant to another plant
Features favoring SP:

  1. Bisexual flower w/ same maturing time
  2. Anther higher than stigma
  3. Flower never open
Features favoring CP:

  1. Unisexual/boisexual flower, dioeciious w/ diff maturing time
  2. Anther lower than stigma


Advantages: only 1 plant, don’t depend on external agentts, efficient, beneficial qualities from parent plant Advantages: more variety

 SEED DISPERSAL by Helen Susanto 

Menyebarkan biji, jadi offspring tidak tinggal dekat induk supaya anak induk tidak ada competition

Dandelion, pohon saga, etc

If ripe seed fall to a suitable place, it will grow = GERMINATION

The favourable condition:  water, oxygen, suitable temperature, sama use storage food (endosperm)

Changes during germination:

  1. Seed absorbs water and swells à cotyledon secretes enzyme to digest storaged food
  2. Food deliver to developing shoot and root
  3. Dry mass decreases for respiratioin growth
  4. First leaf develop
  5. Continued with photosynthesis

Plant Life Cycle estimated time = 7 months

  1. Pollination
  2. Fertilization (create zygote and embryo in seed)
  3. Seed dispersal
  4. Germination (seed à seedling)
  5. Maturation (provide condition to reproduce)
  6. Back to 1

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