Effect of Light upon the Behaviour of Citric Acid in Leaves of Bryophyllum Calycinum Salisb.

Maintenance Carbon Cycle in Crassulacean Acid Metabolism Plant Leaves

“…Analysis of leaves from B. calycinum with chromatography (24) and S. telephium with isocitrate dehydrogenase (3) indicated that no change in leafisocitrate content occurred. In contrast, there is precedent for fluctuations in citrate levels in CAM plant leaves (25) …”

“…3 and 4). Citrate has been shown to undergo relatively small daily changes compared to malate in the leaves of some species of CAM plants (10,15,20,25). Conversely, isocitrate, which is a major component of the leaves of Kalanchoe pinnatum and S. telephium, has been reported to undergo little diurnal fluctuation (3,15,24).…”

“…The percentage of the label that accumulates in these components relative to malate, however, is low. In some species, citrate fluctuates diurnally but the amplitude is three orders of magnitude less than that exhibited by malate (10,15,20,25 …”

Metabolism of Threo-Ds-Isocitric Acid in Detached Leaves of Bryophyllum calycinum

“…In the dark large amounts of malic acid accumulate, presumably in the vacuole, while in the light such stores are depleted (2,5). The behavior of citric acid shows similar fluctuations but of a smaller amplitude (5,14). Isocitric acid, the major organic acid component of some species, shows erratic behavior.…”

A Chemist Among Plants

“…This effect was pre sumably associated with the small loss of protein that was observed. Other experiments dealt with the effect of temperature on the fundamental transfor mation of starch to malic acid which occurs in darkness, and with the effect of light upon the citric acid of leaves collected at sunrise (31). Citric acid behaves in a manner much like that of malic acid although on a lower scale of quantity, but the increases seen in the first few hours of exposure to light, when malic acid is still at a high level although diminishing in amount, led us to conclude that citric acid arises from malic acid by a series of reactions for which there are many analogies in the behavior of these two acids in the tobacco leaf.…”