Ecophysiological investigations on plants of the genus Plectranthus (fam. Lamiaceae) native to Yemen and southern Africa

Herppich, Werner B.; Herppich, Margaretha

doi:10.1016/s0367-2530(17)33117-1

Cited by 13 publications

(3 citation statements)

References 22 publications

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“…Some plants, for example, species of Sempervivum (Wagner and Larcher 1981) and Sedum (Groenhof et al 1986;Gravatt and Martin 1992) in the Crassulaceae, Peperomia (Sipes and Ting 1985) in the Piperaceae, Clusia (Franco et al 1991) in the Clusiaceae, Plectranthus in the Lamiaceae (Herppich and Herppich 1996), and Aptenia in the Mesembryanthemaceae (Herppich and Peckmann 1997), absorb large amounts of C02 during both the day and the night; such plants are often referred to as "C3-CAM intermediates." In addition, an increasing number of taxa exhibit a strictly C3 pattern of C02 exchange with no C02 uptake at night, yet malic acid concentrations in their photosynthetic tissues undergo large diel fluctuations as in obligate CAM plants (Ting 1985;Griffiths 1988;Martin 1996).…”

Section: Discussionmentioning

confidence: 99%

Photosynthetic Pathway Variation in Leafy Members of Two Subfamilies of the Cactaceae

Martin

Wallace

2000

International Journal of Plant Sciences

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Patterns of 24-h C02 exchange and diel fluctuations in tissue acid concentrations were measured in leafy and leafless shoots of 10 species in the Pereskioideae and eight species in the Opuntioideae (Cactaceae). The species were selected to represent a range of phylogenetic histories. Leafy shoots of all species in the Pereskioideae exhibited C3 patterns of gas exchange, and net C02 exchange of leafless stems in all but one species was negative during the day and night. Although nighttime C02 uptake was not observed in shoots or stems of any of the pereskioid taxa, tissue acidity increased at night to a small degree in leaves of six species and stems of five species, indicative of low levels of CAM-cycling. In contrast, in leafy shoots of nearly all species in the Opuntioideae, C02 uptake occurred during the day and the night. Gas-exchange rates were typically greater during the day. As is typical of CAM, nighttime maximal water use efficiency often greatly exceeded daytime values. Tissue malic acid concentrations increased overnight in leaves and stems of all eight opuntioid species. Examination of the data from a phylogenetic perspective illustrates evidence of low levels of CAM scattered among the primarily C3 members of the more ancestral Pereskioideae. Furthermore, such consideration of the taxa in the more derived Opuntioideae (comparing the genera from most ancestral to most derived, that is, Austrocylindropuntia -* Quiabentia -> Pereskiopsis -* Cylindropuntia) revealed that CAM became increasingly less important in the leaves of the various taxa, whereas this water-conservative pathway of photosynthesis became increasingly more important in the stems. The results of this study indicate that members of the Pereskioideae should be restricted to moister habitats or must restrict the timing of growth to wet seasons, whereas the observed combinations of the C3 and CAM pathways in the opuntioid taxa should prove beneficial in conserving water in the sporadically arid tropical and subtropical habitats of these plants.

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Section: Discussionmentioning

confidence: 99%

Photosynthetic Pathway Variation in Leafy Members of Two Subfamilies of the Cactaceae

Martin

Wallace

2000

International Journal of Plant Sciences

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“…Building on observations by Kluge and Ting (1978), who reported nocturnal acidification in Plectranthus prostratus Gürke (now Coleus prostratus (Gürke) A.J. Paton et al 2019), Herppich and collaborators studied the occurrence of CAM in several species of what was then considered Plectranthus native to Yemen and southern Africa (Herppich 1996(Herppich , 1997Herppich and Herppich 1996;Herppich et al 1998). Features of CAM were noted in four of seven species.…”

Section: Introductionmentioning

confidence: 97%

Constitutive and facultative crassulacean acid metabolism (CAM) in Cuban oregano,

et al. 2020

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Plants exhibiting the water-conserving crassulacean acid metabolism (CAM) photosynthetic pathway provide some of the most intriguing examples of photosynthetic diversity and plasticity. Here, a largely unnoticed facet of CAM-plant photosynthesis is highlighted: the co-occurrence of ontogenetically controlled constitutive and environmentally controlled facultative CAM in a species. Both forms of CAM are displayed in leaves of Coleus amboinicus Lour. (Lamiaceae), a semi-succulent perennial plant with oregano-like flavour that is native to southern and eastern Africa and naturalised elsewhere in the tropics. Under well-watered conditions, leaves assimilate CO2 predominantly by the C3 pathway. They also display low levels of CO2 uptake at night accompanied by small nocturnal increases in leaf tissue acidity. This indicates the presence of weakly expressed constitutive CAM. CAM expression is strongly enhanced in response to drought stress. The drought-enhanced component of CAM is reversible upon rewatering and thus considered to be facultative. In contrast to C. amboinicus, the thin-leaved closely related Coleus scutellarioides (L.) Benth. exhibits net CO2 fixation solely in the light via the C3 pathway, both under well-watered and drought conditions. However, low levels of nocturnal acidification detected in leaves and stems indicate that the CAM cycle is present. The highly speciose mint family, which contains few known CAM-exhibiting species and is composed predominantly of C3 species, appears to be an excellent group of plants for studying the evolutionary origins of CAM and for determining the position of facultative CAM along the C3–full CAM trajectory.

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“…The aim of this controlled-environment study was to investigate the relationship between changes in air humidity and leaf conductance and its potential functional link to nocturnal net carbon uptake and malic acid accumulation in the obligate CAM plant P. marrubioides (Herppich & Herppich 1996). Furthermore, it was of interest whether this relationship was modified by variations in soil water availability and leaf temperature.…”

Section: Introductionmentioning

confidence: 99%

Stomatal responses to changes in air humidity are not necessarily linked to nocturnal CO₂ uptake in the CAM plant Plectranthus marrubioides Benth. (Lamiaceae)

Herppich¹

1997

Plant Cell & Environment

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Plants of the crassulacean acid metabolism (CAM) speciesPlectranthus marrubioides (Lamiaceae) were subjected to short-and long-term changes in air humidity in controUedenvironment experiments. Stomata of well-watered individuals of this all-cell leaf-succulent taxon responded directly, quickly and reversibly to variations of the water vapour gradient between leaf and air {Aw). Mean night-time leaf conductance to water vapour decreased curvilinearly with increasing Aw but linearly with lowered relative air humidity. Stomatal response was generally independent of the prevailing temperature and was not linked to CO2 uptake rates. Therefore, net night-time carbon gain, nocturnal malic acid accumulation and, thus, relative carbon recycling were not influenced by changes in air humidity in the temperature range tested. Mean nocturnal molar water use efficiency, however, decreased with decreasing air humidity because of the increased transpirational water loss. If watering was repeatedly withheld for several days during the experiments, employing a temperature regime of 35/30 °C day and night, stomatal conductance became low enough to inhibit CO2 uptake, but only at the highest Aw. The results suggest that drought stress was necessary to increase responsiveness of plants to the point where CAM was also inhibited by decreases in air humidity.

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Ecophysiological investigations on plants of the genus Plectranthus (fam. Lamiaceae) native to Yemen and southern Africa

Cited by 13 publications

References 22 publications

Photosynthetic Pathway Variation in Leafy Members of Two Subfamilies of the Cactaceae

Photosynthetic Pathway Variation in Leafy Members of Two Subfamilies of the Cactaceae

Constitutive and facultative crassulacean acid metabolism (CAM) in Cuban oregano,

Stomatal responses to changes in air humidity are not necessarily linked to nocturnal CO₂ uptake in the CAM plant Plectranthus marrubioides Benth. (Lamiaceae)

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Ecophysiological investigations on plants of the genus Plectranthus (fam. Lamiaceae) native to Yemen and southern Africa

Cited by 13 publications

References 22 publications

Photosynthetic Pathway Variation in Leafy Members of Two Subfamilies of the Cactaceae

Photosynthetic Pathway Variation in Leafy Members of Two Subfamilies of the Cactaceae

Constitutive and facultative crassulacean acid metabolism (CAM) in Cuban oregano,

Stomatal responses to changes in air humidity are not necessarily linked to nocturnal CO2 uptake in the CAM plant Plectranthus marrubioides Benth. (Lamiaceae)

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Stomatal responses to changes in air humidity are not necessarily linked to nocturnal CO₂ uptake in the CAM plant Plectranthus marrubioides Benth. (Lamiaceae)