The document discusses different types of tubers, which are modified plant structures that store nutrients underground. There are two main types of tubers: stem tubers, such as potatoes, which form from thickened stems; and root tubers, such as sweet potatoes, which form from thickened roots. The document also describes the factors that influence tuber formation, including temperature, humidity, day length, and soil conditions. It provides details on tuber anatomy and the life cycle of potato tubers, which progresses from sprouting to growth, initiation, development, maturity, and dormancy.

1. TUBER

2. KELOMPOK 4
AET 1
• CHRISTIAN NATANAEL TARIGAN / 090301003
• FADMA JUWITA NASUTION / 090301002
• DINA ARSYI FAZRIN / 090301020
• EVI JULIANITHA HARAHAP / 090301022
• BAYHAQI / 090301023
• SISKO BUDIANTO / 090301029
• KUKUH IMAN BUDIONO / 090301030
• NIKKO SEPTIAN FAZILLA / 090301033
• MUHAMMAD RIZKI SIREGAR / 090301041
• ACHMAD HAMBALI NASUTION / 090301053

3. Tuber
Organ tanaman yang membengkak,
modifikasi dari struktur batang atau akar
yang berfungsi sebagai sebuah organ
penyimpanan di bawah tanah.

4. Tubers are various types of modified plant
structures that are enlarged to store nutrient
s. They are used by plants to survive the
winter or dry months and provide energy and
nutrients for regrowth during the next
growing season and they are a means of
asexual reproduction. Two different groups
of tubers are: stem tubers, and root tubers.

5. Faktor-faktor yang Mempengaruhi
Pembentukan Umbi/Tuber :
- Suhu (15-200 C)
suhu optimum 15,6-17,80 C.
- Kelembaban Udara (80-90%)
- Panjang Hari (10-16 jam per hari)
- Suhu Tanah
- Tanggal Tanam
- Umur Fisiologis Umbi
- Karakteristik Budidaya Umbi yang dilakukan

6. Tuberous Stem
A stem tuber forms from thickened rhizomes
or stolons. The tops or sides of the tuber
produce shoots that grow into typical stems
and leaves and the under sides produce
roots. They tend to form at the sides of the
parent plant and are most often located near
the soil surface. The below-ground stem
tuber is normally a short-lived storage and
regenerative organ developing from a shoot
that branches off a mature plant.

7. Stem tubers generally start off as
enlargementof the hypocotyl section of a
seedling but also sometimes include the first
node or two of the epicotyl and the upper
section of the root. The stem tuber has a
vertical orientation with one or a few
vegetative buds on the top and fibrous roots
produced on the bottom from a basal
section, typically the stem tuber has an
oblong rounded shape.

8. Contoh Tanaman Tuberous Stem
Kentang (Solanum tuberosum L.)
Plectranthus esculentus
Anredera cordifolia
Begonia

9. Anatomy of Tuberous Stem

10. The tuber has all the parts of a normal stem, including
nodes and internodes, the nodes are the eyes and
each has a leaf scar. The nodes or eyes are arranged
around the tuber in a spiral fashion beginning on the
end opposite the attachment point to the stolon. The
terminal bud is produced at the farthest point away
from the stolon attachment and tuber thus shows the
same apical dominance of a normal stem. Internally a
tuber is filled with starch stored in enlarged
parenchyma like cells; also internally the tuber has the
typical cell structures of any stem, including a pith,
vascular zones and a cortex.

12. • Tuber eye The buds from which next season's growth will
emerge. Eyes are concentrated near the apical end of the
tuber, with fewer near the stolon or basal end. Eye number
and distribution are characteristic of the variety
• Tuber skin Tuber skin is composed of two layers of cells: an
outer layer of single cells called the epidermis, underlain by
several layers of corky cells called the periderm. The
periderm layer may contain a pigment that produces
coloured potatoes.
• Tuber cortex Tissue between skin and a vascular ring.
• Vascular ring Vascular ring contains cells that transport
nutrients from the above ground stems to the medulla.
• Tuber medulla Medulla represents the primary storage
area for the potato tuber.
• Tuber perimedulla Is located between the vascular ring and
medulla.

13. Tuberous Root
Umbi akar (tuberous root) adalah modifikasi
akar lateral, mengalami pembesaran yang
berfungsi sebagai organ penyimpanan.
Secara harfiah ini berbeda tetapi sama dalam
fungsi dan penampilan pada tuber/umbi
yang sebenarnya. Sebagai contoh tanaman
dengan umbi akar yang jelas adalah sweet
potato (ketela rambat), cassava dan dahlia.
Sebuah umbi akar membuat tanaman untuk
bertahan dari tahun ke tahun.

15. The life cycle of a potato tuber is characterized by initiation and
growth followed by a period of dormancy and finally sprouting
resulting in the next (vegetative) generation.
• Sprouting tuber Growth stage 1. The onset of sprout growth that
follows dormancy termination is accompanied by substantial
increases in cell metabolism; sprouts appear from the eyes of the
primary tuber.
• Vegetative Growth stage 2. Plant establishment. All vegetative
parts of the plants (leaves, branches, roots and stolons) are formed;
stages 1 and 2 last from 30 to 70 days depending on planting date,
soil temperature and other environmental factors, the physiological
age of the tubers, and the characteristics of particular cultivars.
• Tuber initiation Growth stage 3. Approximately 30-60 days after
the seed tuber is planted, tuber formation begins. Tubers are
derived from lateral underground buds developing at the base of
the main stem that when kept underground develop into stolons
due to diagravitropical growth. When the conditions are favorable
for tuber initiation, the elongation of the stolon stops, and cells
located in the pith and the cortex of the apical region of the stolon
first enlarge and then later divide longitudinally. The combination
of these processes results in the swelling of the subapical part of
the stolon.

16. • Developing tuber Growth stage 4. During enlargement tubers
become the largest sink of the potato plant storing massive
amounts of carbohydrates (mainly starch) and also significant
amounts of protein. Furthermore, tubers decrease their general
metabolic activity and as such behave as typical storage sinks.
• Mature tuber Growth stage 5. Potato tubers are harvested from 90
to 160 days after planting and this may vary with cultivars,
production area, and marketing conditions. Starch the typically
represents 20% of the fresh weight of mature tuber. After potato
vines die back the skin of tuber thickens and hardens, which
provides greater protection to tubers during harvest and blocks
entry of pathogens to the tuber.
• Dormant tuber Although dormancy is defined as the absence of
visible growth, dormant meristems are metabolically active. In
general, rates of many cellular processes such as respiration,
transcription, and translation are suppressed during dormancy.
Non-dividing, dormant tuber meristems are arrested in the G-1
phase

17. KESIMPULAN
1. Tuber adalah organ tanaman yang membengkak, modifikasi
dari struktur batang atau akar yang berfungsi sebagai sebuah
organ penyimpanan di bawah tanah.
2. Tuber merupakan modifikasi dari stolon yang membengkak,
karena berisi pati (starch) atau cadangan makanan.
3. Faktor-faktor yang mempengaruhi pembentukan umbi adalah
suhu udara, kelembaban udara, suhu tanah, tanggal tanam,
umur fisiologis umbi, panjang hari dan teknik budidaya.
4. Umbi/tuber terbagi dua yaitu umbi batang (tuberous stem)
seperti kentang (Solanum tuberosum L.), dan umbi akar
(tuberous root) seperti sweet potato (Ipomea batatas L.).
5. Daur umbi terbagi enam yaitu sprouting tuber, vegetatif
growth, tuber initiation growth, develoving tuber growth,
mature tuber growth dan dormant tuber.

18. TERIMA KASIH