Question

Stem modified into flattened photosynthetic structure is?
1. Tendril
2. Bulbil
3. Phylloclade
4. Phyllode
5.

Answer 1

Correct Answer - Option 3 : Phylloclade

The correct answer is Phylloclade.

• Phylloclades and cladodes are flattened, photosynthetic shoots, which are usually considered to be modified branches. Hence, Option 3 is correct.
• Phylloclades are flattened or cylindrical modifications of the stem of unlimited growth which has taken over the function of photosynthesis.
• The formation of phylloclades helps the plant to grow in dry habitats because transpiration is little from the stem. In some cases phylloclades store water, mucilage, and latex, eg., Opuntia.
• The two terms are used either differently or interchangeably by different authors.
• Phyllocladus, a genus of conifer is named after these structures.
• Phylloclades/cladodes have been identified in fossils dating from as early as the Permian.
• By an alternative definition, cladodes are distinguished by their limited growth and that they involve only one or two internodes. By this definition, some of the most leaf-like structures are cladodes, rather than phylloclades. By that definition, Phyllanthus has phylloclades, but Ruscus and Asparagus have cladodes. 

 

• Phyllode: A flattened petiole or leaf rachis that resemble and function as a leaf, and may or may not be combined with an actual lamina.
• Bulbil: Fleshy bud aggregations which are used for vegetative propagation in plants such as Agave, Cycas, Yam plant, etc.
• Phylloclade: Phyllodes and Cladodes are flattened, photosynthetic shoots, which are usually considered to be modified branches.
• Tendril: It is a specialized stem, leaves, or petiole with a threadlike shape that is used by climbing plants for support, attachment, and cellular invasion by parasitic plants, generally by twining around suitable hosts found by touch.