Given below are two statements: Statement I: Phytoalexins are high molecular weight compounds. Statement II: Phytoalexins are all phenolic in nature.

Correct option is D

Phytoalexins are low molecular weight antimicrobial compounds synthesized by plants in response to pathogen attack. Hence, Statement I is incorrect because phytoalexins are not high molecular weight compounds. Phytoalexins are generally phenolic or phenol-derived compounds involved in plant defense mechanisms. Therefore, Statement II is correct while Statement I is incorrect.
Information booster: Phytoalexins are produced only after infection or stress, and not stored in plants beforehand. They inhibit the growth of fungi, bacteria, and other pathogens at infection sites. Different crops synthesize specific phytoalexins, such as rishitin in potato and momilactone in rice. Phytoalexins form an important component of induced resistance in plants.
Why other options are incorrect: (a) This option is incorrect because Statement I is false. (b) This option is incorrect because Statement II is true. (c) This option is incorrect because Statement I is not correct.