1 . Early Stage Growth
The growth of the seeds have been initiated during the process of physics , chemistry , and biology began to take place . At first a process of doing physics when seed imbibition or absorption of water until the seeds grow in size and become soft . When water gets into the seed , the enzymes become active so as to produce a variety of chemical reactions . These enzymes work , among others , activate metabolism in seeds to synthesize food reserves as supplies of food reserves during germination takes place that used to germinate .
2 . germination
Germination is the emergence plantula ( small plants ) from the seed which is the result of the growth and development of the embryo .
At the time of development of the embryo to germinate , grow and develop plumula section into the rod , while the radicle becomes the root . There are two kinds of germination type , type the following .
Type germination above ground ( epigeal ) , this type occurs , if plumula appear above ground level , while the cotyledons remain in the soil .
Type germination underground ( hipogeal ) this type occurs , if plumula and cotyledons emerge above the soil surface .
Food for the growth of embryos obtained from food reserves because it has not required the formation of chlorophyll in photosynthesis . In dicotyledonous plants were obtained from cotyledons , whereas the monocot plants obtained from the endosperm .
3 . Primary growth
After germination phase , followed by the growth of the three primary meristem tissue system that lies at the root and stem . In this phase the plants formed roots , stems , and leaves . Three primary network system is formed as follows .
Protoderm , which will form the outermost layer of the epidermis tissue .
Meristem base that will develop into tissue that fills the base layer in the root cortex and epidermis of the style .
Prokambium , ie the layer that will develop into the central cylinder , ie phloem and xylem .
Primary growth in roots
Young roots coming out of the seed went into the ground , then establish the root system of plants . At the end of the young root , there are four areas of growth as follows .
a. Hood roots ( kaliptra )
Kaliptra hood roots or serves as a protection against physical impact on soil around the root tip growth . Another function the root tip , which is easier for roots to penetrate the soil because the roots hood is equipped with fluid secretion polysaccharides . The difference between monocots and dicots hood roots as follows :
In dicotyledonous root cap , the root tip with kaliptra there are no clear boundaries and do not have a growing point on the kaliptra .
In monocot roots hood , between the root tip and kaliptra there is a clear boundary or real and has its own growing point called kaliptrogen . Kaliptra cells close to the root tip containing a grain flour called columella .
b . meristem
Meristem is part of the root tip cell division by mitosis always hold . Meristem is located behind the root cap . In dicotyledonous plants , the root cap cells are damaged will be replaced by new cells produced by the cells of the primary me - ristem developments apical meristem cells .
c . Regional cell elongation
Elongation of cells located in the area behind the meristem area . Cells results meristem division grow and develop elongated in this area . Activity growth and development of elongated cells resulted in cell division in this area to be slower than other parts . Elongation of these cells play an important role to help power tap root and root elongated growth process .
d . regional differentiation
In this area , the cells division and elongation results will be clustered suits their structural similarity . Cells that have the same structure , then will obtain certain tasks form a network .
Primary Growth in Stems
Growth and development of the area includes a primer on stem growth ( growing point ) , elongation region , and regional differentiation . Apical meristem in the stem is formed by cells that constantly divide at the end of the shoot which is called buds . In the bud , stem segments and leaves small protrusions ( primordia ) have very short distance because the distance internodus ( antarruas ) is very short . Growth , division and cell elongation occurs in the internodus .
4 . Secondary growth
After the primary meristem tissue to form a permanent , then the secondary meristem secondary growth . Secondary growth occurs only in dicotyledonous plants , the cambium formation formed from parenchyma or kolenkim .
If the cambium cells divide outwards , will form the phloem cells , otherwise if the cambium cells divide to form towards the xylem . Xylem and phloem are formed from the cambium activity called secondary xylem and secondary phloem . Xylem and phloem growth causes the trunk grew and formed a circle of which is influenced by activity in the dry season and the rainy season .
Keywords :
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