Plant Growth and Development-1-NCERT

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Stage/Process	Details
1. Development	– Development is the sum of two processes: Growth and Differentiation. – Begins from the Zygote (fertilized egg). – Follows a precise and highly ordered succession of events. – Forms a complex body organization that produces roots, leaves, branches, flowers, fruits, and seeds. – Ends with death after maturation.
2. Cell Division	– Initial stage of development where cell division occurs.
3. Meristematic Cell	– Formation of meristematic cells which are undifferentiated cells capable of division.
4. Plasmatic Growth	– Plasmatic growth begins, contributing to the overall increase in cell size.
5. Expansion (Elongation)	– Cells undergo expansion, leading to elongation and the development of tissues.
6. Differentiation	– Cells specialize into different types of tissues and organs, marking the transition to mature cells.
7. Maturation	– Mature cells undergo further development, contributing to the overall complexity of the plant structure.
8. Aging	– As the plant matures, it begins to age. – Aging involves a sum total of changes in the entire plant or its organs. – Chemical and structural changes occur during aging. – Aging leads to senescence.
9. Senescence	– Senescence is the deteriorative process that naturally terminates the functional life of an organ, organism, or life unit. – It is a phase of the aging process. – Characterized by catabolic metabolic processes that become irreversible and ultimately lead to death. – Senescence occurs at multiple levels: – Whole Plant: E.g., Wheat dies after fruiting. – Organs: E.g., Leaf fall in coconut trees. – Cells or Organelles: Individual cells or their components may undergo senescence.
10. Abscission	– Abscission refers to the shedding of leaves, flowers, and fruits. – Distinct in deciduous plants (all leaves fall at once in autumn) versus evergreen plants (gradual leaf fall throughout the year). – In many herbaceous species, leaves may not be shed even when dead. – During abscission, there are changes in pigmentation due to the degradation of chlorophyll and the synthesis of anthocyanin pigments.
11. Death	– Final stage of development. – Results from senescence, where metabolic processes cease, leading to the termination of plant life. – Involves abscission (shedding of non-functional parts).
12. Determinate Growth	– Growth that stops after reaching a certain size or maturity; e.g., leaves and flowers grow to a specific size and then cease.
13. Indeterminate Growth	– Growth that continues throughout the plant’s life; e.g., roots and stems can keep growing as long as the plant is alive and resources are available.
14. Open Growth	– Indicates the presence of both determinate and indeterminate growth within the plant; some parts (like leaves) have fixed growth while others (like roots) do not.
15. Open Differentiation	– Suggests that the final form or function of plant cells is not predetermined, allowing cells to adapt and differentiate based on their environment.