# DBT JRF 2022 — Question 86

Exam: DBT JRF 2022 · Section: B · Topic: Plant Biology › Hypersensitive Response & Plant Immunity · Difficulty: Medium

## Question

Which one of the following is NOT a typical feature of the hypersensitive response observed in plants during the attack of invading microbes?

## Options

- **A.** Onset of programmed cell death in the region surrounding the infection site
- **B.** Rapid accumulation of reactive oxygen species
- **C.** Rapid spike in photosynthetic rate
- **D.** Rapid spike in nitric oxide production accompanying the oxidative burst

## Answer

Option C

## Explanation

Hypersensitive Response (HR) in plants — what does NOT occur: The Hypersensitive Response (HR) is a rapid, localised programmed cell death at the site of pathogen infection: Features of HR: • Rapid cell death (programmed apoptosis-like) at infection site • • Reactive oxygen species (ROS) burst (superoxide, H2O2) • • Nitric oxide (NO) production • • Salicylic acid signalling → systemic acquired resistance (SAR) • • Cell wall reinforcement (lignification, callose deposition) • • Antimicrobial phytoalexin accumulation • What does NOT occur during HR: • Photosynthetic rate INCREASE: During HR, resources are redirected toward defence responses. Chloroplasts can actually be disrupted and photosynthesis is typically SUPPRESSED (not increased) in infected tissue. Answer: Photosynthetic rate is NOT increased during HR; it is typically suppressed as resources redirect to defence.

Source: https://mypyqbuddy.com/questions/which-one-of-the-following-is-not-a-6a104cd5920734408bc0c765