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Euryodendron excelsum is a rare and endangered evergreen tree in South China. We conducted two experimental translocations (augmentation and conservation introduction) on this species and assessed morphological, anatomical and physiological traits of leaves after translocation. The introduction plants showed smaller specific leaf area, less developed palisade tissues, smaller palisade/spongy tissue ratio, stomata density and anthocyanin content, lower values of maximal quantum yield of PSII photochemistry, photochemical quenching coefficient, net photosynthetic rate, light-saturated net photosynthetic rate, light-saturation point, but higher light-compensation point. These differences in traits help explain why augmented plants grew faster than introduced plants. We found that E. excelsum can adapt to wide ranges of light intensity and water availability, including conditions encountered at the introduction site. Our findings suggest that some endemic and endangered plants with narrow distribution may adapt to different habitat conditions by rapidly altering their morphological, anatomical, and physiological traits. [ABSTRACT FROM AUTHOR]

In order to explore the adaptive strategies of tree peony yl1 mutant in response to photooxidative stress, the changes of biochemical parameters, chlorophyll fluorescence, and the modulated 820-nm reflection of yl1 mutant and wildtype plants were compared. We found the activities of superoxide dismutase and catalase, the contents of soluble protein, proline, superoxide radicals, hydrogen peroxide, malondialdehyde, and relative electrical conductivity were significantly higher than those of the wild type. The photochemical efficiency of PSII significantly decreased, while the proportion of heat dissipation of yl1 mutant increased greatly. The donor and acceptor side and electron transfer of PSII were greatly inhibited. Meanwhile, the performance of PSI and coordination of two photosystems decreased markedly in yl1 mutant. The yl1 mutant could reduce the damage caused by photooxidative stress by increasing the activity of antioxidant enzymes, the content of some osmoregulatory substances, and the proportion of heat dissipation. [ABSTRACT FROM AUTHOR]

Tree peony is a famous ornamental plant in the world. However, little is known about the leaf color mutants in tree peony. The present study monitored the physiological and photosynthetic properties of a yellow leaf mutant (yl1) in tree peony. The results showed that the yl1 mutant had lower pigment contents, but increased chlorophyll (Chl) a/b and carotenoids to Chl ratio. Microstructure and ultrastructure analysis showed that the yl1 mutant had smaller chloroplasts, few thylakoid stacks, and a few stroma thylakoid membranes remained along with clusters of osmiophilic granules, which might result from inhibition at the reactions from coproporphyrinogen III to protoporphyrin IX. The yl1 mutant had lower leaf net photosynthetic rate, stomatal conductance, transpiration rate, and stomata limitation value, but higher intercellular CO2 concentration. Analysis of simple sequence repeat markers indicated that four pairs of primers could obtain different bands in the genome of the yl1 mutant compared to the wild type. [ABSTRACT FROM AUTHOR]

Primulina tabacum Hance is an endangered perennial herb distributed in calcium-rich and nitrogen-limited soil of the karst limestone areas in southern China. The morphological, ultrastructural, and physiological traits were determined for P. tabacum populations growing in three different environment conditions: twilight zone of a cave (site TZ, extremely low light intensity), at a cave entrance (site EZ, low light intensity), and in an open area (site OA, high light intensity). At site OA, P. tabacum plants were exposed to high light (635 μmol m s of mean daily photosynthetically active radiation) with drought stress, and expressed traits to minimize light capture and water loss. Compared to plants at sites EZ and TZ, those at site OA had thicker leaves with higher densities of stomata and pubescence, higher palisade/spongy ratio, higher light-saturated rate of net photosynthetic rate ( P), higher biomass, higher non-photochemical quenching coefficient (NPQ), and higher light saturation point (LSP) but fewer grana per chloroplast and less thylakoid stacking per granum. In contrast, P. tabacum growing at the cave vicinities: EZ (mean daily irradiance 59 μmol m s) and TZ (mean daily irradiance 11 μmol m s) showed typical shade-adapted characteristics for optimum light capture. The presence of sun- and shade-adapted characteristics indicates that P. tabacum has different strategies to cope with different environments but whether these strategies reflect genetic selection or phenological plasticity is yet to be determined. Such variability in physiological and morphological traits is important for the survival of P. tabacum in heterogeneous light conditions. [ABSTRACT FROM AUTHOR]