Question 1

What is totipotency and why is it important in plant tissue culture?

Accepted Answer

Totipotency is the ability of a plant cell or tissue to develop into an entire new plant when provided with appropriate growth medium and environment. This fundamental principle enables plant tissue culture to rapidly produce large numbers of genetically identical plant clones with desired qualities, making it far more efficient than traditional breeding methods that require many generations.

Question 2

How do plant hormones control the formation of roots and shoots in callus culture?

Accepted Answer

Plant hormones, particularly auxins and cytokinins, regulate cell differentiation in callus tissue. High cytokinin-to-auxin ratios promote shoot formation, while reversed ratios favor root development. Equal hormone concentrations produce both roots and shoots simultaneously, allowing regeneration of complete young plants from undifferentiated callus cells.

Question 3

Why is meristem culture particularly useful for producing virus-free plants?

Accepted Answer

Meristem culture uses the rapidly dividing shoot tip as the explant, which is generally free of viruses that typically infect other plant tissues. This method is particularly valuable in agriculture because viruses cause serious plant diseases, and establishing virus-free plants through meristem culture prevents disease transmission and improves crop health and productivity.

Question 4

What are the four fundamental steps required for successful plant tissue culture?

Accepted Answer

Plant tissue culture requires selecting a healthy parent plant explant, eliminating microbial contamination from exposed surfaces, inoculating the explant in adequate culture medium, and incubating it in a controlled environment with appropriate temperature, humidity, air quality, and illumination. These steps ensure optimal conditions for plant regeneration and growth.

Question 5

How does plant tissue culture enable genetic modification of crops?

Accepted Answer

Plant tissue culture facilitates genetic modification by allowing beneficial genes to be introduced into plant cells, which then regenerate into complete modified plants. These modifications are inherited by subsequent generations, producing desirable traits like herbicide tolerance without requiring repeated tissue culture, as demonstrated by genetically modified crops widely adopted in agriculture.

Question 6

What is micropropagation and which plants benefit most from this technique?

Accepted Answer

Micropropagation is in vitro clonal propagation using plant tissue culture to rapidly produce multiple identical plants. It is particularly valuable for plants with recalcitrant seeds or short seed viability, commercially important species, and endangered plants. For example, orchids like Paphiopedilum delenatii are micropropagated to ensure commercial viability and species conservation.

Question 7

How does plant tissue culture compare to traditional crop breeding methods?

Accepted Answer

Traditional breeding through grafting or cross-pollination requires many generations and is time-consuming and non-specific, often eliminating desired traits. Plant tissue culture rapidly produces large numbers of genetically identical clones with desired qualities, offering a faster, more reliable alternative for crop improvement and the development of new plant varieties.

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