Growth irreversible increase

in volume– cell expansion driven by turgor pressure– sum of local cell expansions

Measures of plant growth

increase in cell volume

increase in dry weight

increase in cell number

(unicellulars)

fractional change in length per unit time. magnitude and location of extension rate

r = (1/L)(dL/dt).

Relative elemental growth

rate

Pertumbuhan & Perkembangan

PERTUMBUHAN • Yaitu proses pertambahan jumlah,

bentuk, ukuran serta fungsi sel akibat adanya pembelahan sel.

• Bersifat kuantitatif, dapat diukur dengan suatu alat ukur tertentu, serta dapat terlihat secara fisik.

• Bersifat irreversibel • Untuk tanaman dapat diukur dengan

Auksanometer (busur tumbuhan pada tanaman). Untuk manusia dan hewan dengan menggunakan alat ukur yang beragam.

PERKEMBANGAN • Yaitu proses menuju kedewasaan

(kematangan pada sel). • Bersifat kualitatif dan tidak dapat

diukur dengan suatu alat. • Ditandai dengan berfungsinya alat-alat

reproduksi pada makhluk hidup. • Untuk tanaman dengan keluarnya

bunga serta buah. Untuk manusia dan hewan dengan mulai berfungsinya alat reproduksi yaitu menghasilkan sel gamet jantan (sperma) dan sel gamet betina (ovum), serta melangsungkan keturunan.

Pertumbuhan & Perkembangan

The Growth Hormones

IAAs and compounds of same

biological activities – promote cell elongation– promote cell division– form adventitious roots

shoot apical meristems young leaves developing fruits and seeds all parts of plant

Synthesis sites of IAA

Concentrations of IAA in different regions of the shoot of a wild-type tobacco plant. The bars at the different regions indicate the auxin concentrations found in leaves and stems. (After Sitbon et al. 1991.)

Apical dominanceInhibition of the growth of lateral buds

by growing apical bud Maintain cell viability

delay in the onset of leaf abscision regulation of the floral bud development promotion of fruit development

Penyembuhan luka dan keterlibatan

auxin

Auxin

Pengembangan selPhototropismeGeotropismeApical dominasiPertumbuhan akar (root initiation)ParthenocarpyAbisissionPembentukan callus (callus formation) danRespirasi Pengembangan sel

Gibberellins

stimulate stem elongation by stimulating cell division and elongation

stimulates bolting/flowering in response to long days

breaks seed dormancy in some plants which require stratification or light to induce germination

stimulates enzyme production (a-amylase) in germinating cereal grains for mobilization of seed reserves

can cause seedless (parthenocarpic) fruit development

can delay senescence in leaves and citrus fruits

Gibberelins

• Difference between Auxin & Gibberellin:

AUXIN GIBBERELLIN

regulates elongation in grass seedlings and herbs

controls elongation in the mature regions of trees and shrubs

stimulates only cellular elongation

stimulates cell division and elongation

Can NOT tolerate high levels of auxin

can tolerate high levels of gibberellin

has more of an effect on roots

has little effect on roots

Cytokinins• Found in active dividing

structures, seeds, fruits, leaves and root tips

• Central to tissue culture methods and extremely important in biotech.

• modifying apical growth.• The cytokinin/auxin ratio

regulates the production of roots and shoots in tissue cultures

AUXIN VS CYTOKININAuxins: • - They are produced in the apical part of

the plant.- They prevent the development of the axillary buds. - They favour the rhizogenesis ...(development of roots).

Cytokinins: • - They are produced in the roots.

- They prevent the development of roots.- They favour the development of the axillary buds.

Ethylene

• Plays a role in fruit ripening• Promotes abscission (shedding of leaves,

flowers and fruit)– Triggers enzymes that promote fruit

loosening from trees

Auxin prevents abscission (prevents preharvest)

High concentration does the opposite

Abscisic Acid (ABA)• First discovered as dormin and abscisin• Dormin ash and potatoes• In other plants abscisin• Identical compounds now called Abscisic

acid• Levels increase during early seed

development• Stimulates the productio of seed storage

protein• Prevents premature seed germination• Decline in ABA leads to germination