Temperate forest herbs are adapted to high air humidity — evidence from climate chamber and humidity manipulation experiments in the field

2009 ◽  
Vol 39 (12) ◽  
pp. 2332-2342 ◽  
Author(s):  
Jasmin Lendzion ◽  
Christoph Leuschner

How growth and morphology of wild plants are controlled by the water vapor saturation deficit of the air (vapor pressure deficit, VPD) is not sufficiently understood. We tested the hypothesis that VPD acts on temperate woodland herbs independently from soil moisture by exposing two species ( Mercurialis perennis L. and Stachys sylvatica Torr.) to variable VPD levels in climate chambers and in open-top chambers on the forest floor. A decrease in air humidity from 85% to 40% in the climate chamber experiment, which simulates a microclimate change after canopy gap creation, resulted in a 40% decrease in biomass production of both species when grown in hydroponic culture. This result is supported by the more realistic open-top chamber experiment, which showed a productivity decrease by approximately 25% when plants were continuously exposed to an atmosphere with 15% lower air humidity than ambient. Elevated VPD levels reduced biomass production through either a reduced leaf expansion rate or a lower number of formed leaf buds. We conclude that many woodland herbs require sufficiently high air humidity for optimal growth; permanently decreased air humidity, as may occur in a future drier climate, after gap creation, or after clear-cutting of the forest, may threaten the vitality and survival of woodland herbs.

2020 ◽  
Vol 21 (5) ◽  
Author(s):  
Nuril Hidayati ◽  
Dwi Setyo Rini

Abstract. Hidayati N, Rini DS. 2020. Assessment of plants as lead and cadmium accumulators for phytoremediation of contaminated rice field. Biodiversitas 21: 1928-1934. Heavy metals contamination in agricultural land becoming a serious problem since this causes declining in agriculture production and quality and thus food safety. Meanwhile, conventional efforts for remediation of the contaminated agricultural lands have not been widely implemented due to high-cost constraints. A low-cost technology that can be applied in contaminated sites is phytoremediation. This technique is based on the fact that plants have the ability to extract and accumulate heavy metals. This research aimed to study the potentials of some plant species as accumulators for phytoremediation in rice fields contaminated by heavy metals of lead (Pb) and cadmium (Cd). Six selected accumulator plant species, namely Colocasia sp., Ipomoea fistulosa Mart. ex Choisy, Eichhornia crassipes (Mart.) Solms, Hymenachne amplexicaulis (Rudge) Nees), Saccharum spontaneum L., and Acorus calamus L., were tested in in-situ field to identify the performance of the plants as accumulators for Pb and Cd. Parameters observed were plant growth and biomass production, and the accumulation of Pb and Cd in plants which is formulated as: bioconcentration factor (BCF) to indicate concentration ratio of metal in plant to soil, and translocation factor (TF) to indicate metal transportation ratio of shoot to root. The results showed that plants with the highest growth rate under contaminated conditions were E. crassipes, A. calamus, and H. amplexicaulis. The highest value of BCF for Pb accumulation was recorded in the shoot of H. amplexicaulis and E. crassipes and in the root of H. amplexicaulis and A. calamus, whereas the highest value of TF for Pb was observed in E. crassipes, S. spontaneum, and H. amplexicaulis. Meanwhile, the highest value of BCF for Cd in the shoot and in the root was observed in Colocasia sp and H. amplexicaulis whereas the highest value of TF for Cd was identified in A calamus and Colocasia sp. With regards to the performance of plant growth, biomass production, and accumulation of Pb and Cd, it is suggested that three plant species, namely E. crassipes, A. calamus, and H. amplexicaulis are considered as potential Pb and Cd accumulators for phytoremediation of contaminated rice fields. Our findings suggest that some plants can produce high biomass and absorb high contaminants while other plants cannot, implying that plants respond differently to different environmental conditions. Therefore continuous research is required to obtain the best plant species for phytoremediation.


2021 ◽  
Vol 4 (1) ◽  
pp. 171-178
Author(s):  
Uchenna Nwanodi Nwankwo ◽  
Obioma Kenechukwu Agwa

Biofuel serves as an alternative energy to the common fossil fuels currently in use globally and are drawing increasing attention worldwide as substitutes for petroleum-derived transportation fuels to help address challenges associated with petroleum derived fuels. Third generation biofuels, also termed advanced biofuels, are produced from fast growing microalgae and are potential replacements for conventional fuels. The growth and biomass production of these microalgae is dependent on the conditions they are cultivated such as pH and Salinity. Cassava waste mixtures were cultivated on Chlorella vulgaris stock culture at different concentration ratio at ambient temperature, natural light and dark conditions at 670nm absorbance for 14 days. Optimum growth was obtained at 160:40 for cassava peel water to cassava waste water CP:CW. pH variations 6.0, 6.5, 7.0, 7.5, 8.0, 8.5 and 9.0 were checked to determine the optimum pH for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. It revealed that at pH 6.5, optimal growth and biomass production was achieved, minimal growth was observed at pH 8.0 while minimal biomass was produced at pH 9.0. Salinity variations of 5, 10, 15, 20, 25, 30, 35 and 40 mg/l were used to determine the growth response and biomass production of Chlorella vulgaris. It revealed that salinity variation at 10ppm will be necessary for highest growth on the cassava waste as well as in biomass production. The use of optimal pH and salinity can significantly increase biomass production thus enhancing biofuel production.


2021 ◽  
Vol 18 (19) ◽  
pp. 5363-5380
Author(s):  
Johannes Hepp ◽  
Christoph Mayr ◽  
Kazimierz Rozanski ◽  
Imke Kathrin Schäfer ◽  
Mario Tuthorn ◽  
...  

Abstract. The hydrogen isotope composition of leaf-wax-derived biomarkers, e.g., long-chain n-alkanes (δ2Hn-alkane), is widely applied in paleoclimate. However, a direct reconstruction of the isotope composition of source water based on δ2Hn-alkane alone is challenging due to the enrichment of heavy isotopes during evaporation. The coupling of δ2Hn-alkane with δ18O of hemicellulose-derived sugars (δ18Osugar) has the potential to disentangle this limitation and additionally to allow relative humidity reconstructions. Here, we present δ2Hn-alkane as well as δ18Osugar results obtained from leaves of Eucalyptus globulus, Vicia faba, and Brassica oleracea, which grew under controlled conditions. We addressed the questions of (i) whether δ2Hn-alkane and δ18Osugar values allow reconstructions of leaf water isotope composition, (ii) how accurately the reconstructed leaf water isotope composition enables relative humidity (RH) reconstruction, and (iii) whether the coupling of δ2Hn-alkane and δ18Osugar enables a robust source water calculation. For all investigated species, the n-alkane n-C29 was most abundant and therefore used for compound-specific δ2H measurements. For Vicia faba, additionally the δ2H values of n-C31 could be evaluated robustly. Regarding hemicellulose-derived monosaccharides, arabinose and xylose were most abundant, and their δ18O values were therefore used to calculate weighted mean leaf δ18Osugar values. Both δ2Hn-alkane and δ18Osugar yielded significant correlations with δ2Hleaf water and δ18Oleaf water, respectively (r2=0.45 and 0.85, respectively; p<0.001, n=24). Mean fractionation factors between biomarkers and leaf water were found to be −156 ‰ (ranging from −133 ‰ to −192 ‰) for εn-alkane/leaf water and +27.3 ‰ (ranging from +23.0 ‰ to 32.3 ‰) for εsugar/leaf water, respectively. Modeled RHair values from a Craig–Gordon model using measured Tair, δ2Hleaf water and δ18Oleaf water as input correlate highly significantly with modeled RHair values (R2=0.84, p<0.001, RMSE = 6 %). When coupling δ2Hn-alkane and δ18Osugar values, the correlation of modeled RHair values with measured RHair values is weaker but still highly significant, with R2=0.54 (p<0.001, RMSE = 10 %). Finally, the reconstructed source water isotope composition (δ2Hs and δ18Os) as calculated from our coupled approach matches the source water in the climate chamber experiment (δ2Htank water and δ18Otank water). This highlights the great potential of the coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach for paleoclimate and relative humidity reconstructions.


1993 ◽  
Vol 23 (6) ◽  
pp. 1233-1239 ◽  
Author(s):  
David Paré ◽  
Keith Van Cleve

Nutrient content and biomass of aboveground annual production, and nutrient content of total aboveground biomass, of 14-year-old assemblages of plants developing on harvested white spruce (Piceaglauca (Moench) Voss) sites were estimated by vegetation harvesting and compared with values previously measured in mature white spruce stands. The aboveground biomass production of 14-year-old regenerating trembling aspen (Populustremuloides Michx.) clumps was 3 times higher than the aboveground production of mature white spruce stands, while the aboveground production of other regenerating communities was lower or equivalent to the production of mature white spruce. However, the nutrient content of aboveground current biomass was greater in all regenerating communities than in mature white spruce stands, except on regenerating sites where the forest floor was absent. The amount of nutrient incorporated in current aboveground biomass was 5 times greater in trembling aspen clumps than in mature white spruce stands. Furthermore, the total N, P, and K content of aboveground vegetation corresponded, in 14-year-old trembling aspen clumps, to a value that ranged from 50 to 109% of the amount found in the aboveground biomass of mature white spruce forests, while this value ranged from 4 to 14% on other regeneration types. Trembling aspen and balsam poplar (Populusbalsamifera L.) both showed the greatest concentrations of N and P in foliar litter fall. These observations suggest that the development of a trembling aspen clump after clear-cutting contributes to the acceleration of nutrient cycling. On the other hand, the development of herbaceous communities during the same period after clear-cutting was accompanied by much lower nutrient cycling rates in the aboveground portion of the vegetation.


2011 ◽  
Vol 91 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Adel Dhief ◽  
Raoudha Abdellaoui ◽  
Mohamed Tarhouni ◽  
Azaiez Ouled Belgacem ◽  
Samira Ashi Smiti ◽  
...  

Dhief, A., Abdellaoui, R., Tarhouni, M., Belgacem, A. O., Smiti, S. A. and Neffati, M. 2011. Root and aboveground growth of rhizotron-grown seedlings of three Tunisian Desert Calligonum species under water deficit. Can. J. Soil Sci. 91: 15–27. In southern Tunisia, plants are subjected to severe drought and many human disturbances, causing the degradation of soils and plants. The study of wild plants and their response to water deficit can facilitate their conservation and help in ecosystem rehabilitation. In this context, the adaptive responses to water deficit of three desert Calligonum species (C. comosum L'Herit, C. azel Maire and C. arich Le Houerou), differing in their topographic location, were studied in rhizotrons under two water regimes. The objectives were to correlate the adaptive ability of these species, with several developmental traits, such as root architecture and growth, aerial growth and height, with environmental and soil properties, and to define which of the three Calligonum species is best adapted to water stress. Water deficit was applied when plants formed two green branches, and measurements were carried out over 8 mo. Under water deficit, all species increased their cumulative root length. In deeper soil layers, only treated C. arich plants developed secondary roots. Under drought, C. azel and C. arich increased their biomass production during the experiment. It seems that C. arich has adapted better to water deficit by developing a deep root system and the greatest root and aboveground biomass. Hence, C. arich is suggested as the best species for early dune stabilization and biomass production.


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