Page 54 - Hybrid PBD 2022 Tg 5 - Biology

Biologi Tingkatan 5 Bab 2
– Pada keamatan cahaya rendah, kadar transpirasi adalah terhad.

At low light intensity, the rate of transpiration is limited.
– Apabila keamatan cahaya meningkat, stoma akan terbuka, lebih banyak wap air tersejat keluar
daripada daun./ When the light intensity increases, the stomata open, more water evaporates out from the leaves.

– Kadar transpirasi meningkat. / Rate of transpiration increases.
– Sehingga menjadi malar pada suatu keamatan cahaya tertentu.

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Until it becomes constant at certain light intensity.
– Disebabkan oleh faktor pengehad seperti kelembapan relatif udara, suhu dan pergerakan udara.
Due to the limiting factor such as the relative air humidity, temperature and air movement.

(d) Berdasarkan graf di bawah, terangkan mengenai faktor pergerakan udara terhadap kadar transpirasi.
Based on the graph below, explain about the air movement factor that affects the rate of transpiration. TP3 KBAT Mengaplikasi

Kadar transpirasi Transpiration rate

Kelajuan angin
Wind velocity
– Dalam keadaan udara tidak bergerak, kadar transpirasi rendah.
In still air, the rate of transpiration is low.
– Wap air yang meresap keluar daripada daun akan berkumpul di sekitar stoma.

The water vapour that diffuses out from the leaves will accumulate around the stomata.
– Hal ini akan mengurangkan kecerunan kepekatan wap air antara ruang dalam daun dengan udara

persekitaran.
This situation will reduce the concentration gradient of water vapour between the air spaces inside the leaf with the surrounding air.
– Semakin tinggi kelajuan angin, semakin tinggi kadar transpirasi.

The higher the wind speed, the higher the rate of transpiration.
– Pergerakan angin menyingkirkan molekul air berdekatan stoma. Maka, lebih banyak molekul air

akan meresap keluar lalu tersejat melalui stoma.
The wind movement removes the water vapour around the stomata. Thus, more water molecules will diffuse out and evaporate
through the stomata.

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02 HYBRID PBD BIOLOGY TG5.indd 29 18/11/2021 11:05 AM