Plant virology: through which transient pores do many plant viruses penetrate host cells? Choose the classical term used for the transient surface pores implicated in viral entry into plant cells.

Introduction / Context:
Unlike animal viruses that bind receptors on a plasma membrane, many plant viruses rely on breaches or specialized transient pathways to cross the rigid cell wall. Historical plant virology literature uses distinct terms for structures involved in entry versus cell-to-cell spread. This question targets that terminology.

Given Data / Assumptions:

• Plant cell walls limit direct viral entry; vectors (insects, tools) and transient pores can facilitate penetration.
• Once inside, viruses often move cell-to-cell via intercellular channels.
• The options list several “-desmata” terms historically used in plant anatomy and virology.

Concept / Approach:
“Ectodesmata” refers to transient pores or channels across the cell wall surface through which materials (and, in classical descriptions, viruses) can penetrate into a plant cell. By contrast, “plasmodesmata” are permanent intercellular channels that permit direct cytoplasmic continuity, crucial for cell-to-cell spread after entry, not initial penetration. The other terms are not standard for entry.

Step-by-Step Solution:
Differentiate initial penetration from intercellular movement.Recall the classical term “ectodesmata” for transient entry pores.Recognize plasmodesmata are used mainly for cell-to-cell transport post-entry.Select “Ectodesmata.”

Verification / Alternative check:
Older plant pathology texts describe ectodesmata in the context of nutrient and virus passage through the wall; modern literature emphasizes mechanical/vector-mediated entry and movement proteins dilating plasmodesmata for spread, consistent with entry versus spread distinction.

Why Other Options Are Wrong:

• Plasmodesmata: primarily for cell-to-cell movement, not initial penetration.
• Endodesmata, cytodesmata, protodesmata: not accepted standard terms for viral entry pores in plant cells.

Common Pitfalls:
Equating plasmodesmata with entry structures. They are critical for systemic movement, but the question asks specifically about entry pores, historically termed ectodesmata.

Final Answer:
Ectodesmata.