Degeneration of leaf cells resulting from starvation after excision. II. Correlation with water movement and effect on virus synthesis

Abstract

Excised Nicotiana glutinosa leaves increased their transpiration rate during the first 24 h of detachment to 1.5 times the rate of attached control leaves. Thereafter, the transpiration rate decreased to ca. 30% of the controls, without change in fresh weight. The turgidity of the excised leaves at low levels of water movement under normal atmospheric conditions was considered to reflect a state of cell hydration resulting in intracellular rearrangements and hydrolytic changes. Leaves exposed to starvation stress caused by excision for 96 h before TMV infection produced fewer lesions and less virus per cell than the appropriate controls. The lower overall virus level in the starved cells was the net result of a much reduced production of nearly standard-sized particles (270–330 mμ), and an increased production of short (30–170 mμ) particles. Viral production in cells exposed to starvation stress after inoculation, in normal atmosphere, was 15 times lower than was reported for 100% humidity. TMV-infected tissue effected intracellular changes in neighboring uninfected cells exposed to starvation stress.