TRANSPORT SYSTEM IN PLANTSWilting occurs in non-woody plants when the rate of water loss is faster than the rate of absorption of water by the roots.Cells in the plants lose their turgidity (stiffness) and the plant droops.

Transpiration is a process by which water is lost in the form of water vapour from the surface of a plant into the air by evaporation.

STOMATAStomata are pores in the epidermis of the leaves and stems.A pair of bean-shaped guard cells bound each stoma.Most stomata open during the day and close at night.

Monocotyledons Stomata occur only in the lower epidermis of the leaf

Dicotyledons Stomata are found on both sides of the leaf

Water vapour is lost through the stomata. Gases such as oxygen and carbon dioxide diffuse in and out of the leaf through the stomata during photosynthesis and respiration.

However, the stomata will close when transpiration exceeds water absorption.

FACTORS AFFECTING THE RATE OF TRANSPIRATIONA simple way to estimate the transpiration rate of plant is to measure its loss in weight using a weight potometer.It can be used to compare the transpiration rates of the same plant under different conditions.

3. The rate of transpiration is affected by these factors :NUMBER OF STOMATALIGHTTEMPERATUREHUMIDITYWIND

Number of stomataA greater number of stomata increases the rate of transpiration.Light Light stimulates the opening of stomata.The high intensity of light increases the rate of transpiration.

Temperature Water molecules move faster in warm air.The warm temperature increases the rate of transpiration.Humidity High humidity reduces water loss and decreases the rate of transpiration.

Wind An increase in wind speed increases the rate of transpiration.It is because the movement of air carries away the water vapour from the stomata.

THE ROLES OF TRANSPIRATIONTransport water and minerals in the plant.

To cool the plants.To get rid excess water from the plants

VASCULAR TISSUES OF A PLANTThe transport system in flowering plants consist of two conducting tissues, the xylem and the phloem.

a. xylem transports water and mineral salts from the roots to the leaves for photosynthesis and to replace water lost during transpirationb. phloem transports food produced in the leaves by photosynthesis to other parts of the plant.

The arrangement of vascular bundle in monocotyledon plantsThe arrangement of vascular bundle in dicotyledon plants

SISTEM PENGANGKUTAN DI DALAM TUMBUHANTumbuhan tidak berkayu menjadi layu disebabkan oleh kadar kehilangan air berlaku lebih cepat berbanding kadar penyerapan air oleh akar.

Transpirasi ialah proses di mana air tersejat daripada permukaan daun ke udara di dalam bentuk wap air.

STOMATAStomata ialah liang yang terdapat di permukaan epidermis daun dan batang.Setiap stoma terdiri daropada sepasang sel pengawal.Kebanyakan stoma terbuka pada waktu siang dan tutup pada waktu malam.

Fungsi stomata ialah :Membenarkan air keluar semasa transpirasiMembenarkan gas oksigen dan karbon dioksida keluar dan masuk semasa proses respirasi dan fotosintesis

Walaubagaimanapun, stomata akan tertutup apabila kadar transpirasi (penyejatan air) lebih tinggi dari penyerapan air.

FAKTOR YANG MEMPENGARUHI KADAR TRANSPIRASIKaedah potometer boleh digunakan untuk mengukur kadar transpirasi pokok dengan melihat kadar kehilangan beratnya.Ia boleh digunakan pada pokok yang sama tetapi dalam keadaan yang berbeza.

3. Kadar transpirasi dipengaruhi oleh faktor-faktor berikut :Bilangan stomataCahaya Suhu Angin/ kelajuan udara Kelembapan

Bilangan stomataSemakin tinggi bilangan stomata, semakin tinggi kadar transpirasi.Cahaya Cahaya meransang pembukaan stomata. Keamatan cahaya yang tinggi menyebabkan kadar transpirasi juga tinggi.SuhuMolekul air bergerak pantas di dalam udara yang panas. Suhu yang tinggi menyebabkan kadar transpirasi juga tinggi.

KelembapanKelembapan yang tinggi (udara lembab) menyebabkan kadar transpirasi berkurangan.Angin / Kelajuan udara Angin yang bergerak laju menyebabkan kadar transpirasi tinggi.Ini kerana angin membantu membawa molekul air dari stomata.

PERANAN TRANSPIRASIMengangkut air dan garam mineral di dalam tumbuhan.

Menyingkirkan air berlebihan dari tumbuhan.Menyejukkan tumbuhan.

TISU VASKULAR DI DALAM TUMBUHANTisu pengankut di dalam tumbuhan terdiri daripada floem dan xilem.a. xilem membawa air dan garam mineralb. floem membawa makanan (glukosa/gula).

The arrangement of vascular bundle in monocotyledon plantsThe arrangement of vascular bundle in dicotyledon plants