scholarly journals Does Plant Size Influence Leaf Elements in an Arborescent Cycad?

Biology ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 51 ◽  
Author(s):  
Thomas E. Marler ◽  
Murukesan V. Krishnapillai
Keyword(s):  
Plant Size ◽  
Leaf Nitrogen ◽  
Nutrient Concentrations ◽  
Stem Height ◽  
Nitrogen Resorption ◽  
Leaf Nutrient Concentrations ◽  
Phosphorus And Potassium ◽  
Senesced Leaves ◽  
Nitrogen Resorption Efficiency ◽  
Nutrient Relations

Plant size influences the leaf nutrient relations of many species, but no cycad species has been studied in this regard. We used the arborescent Cycas micronesica K.D. Hill to quantify leaf nutrient concentrations of trees with stems up to 5.5-m in height to determine if height influenced leaf nutrients. Green leaves were sampled in a karst, alkaline habitat in Rota and a schist, acid habitat in Yap. Additionally, senesced leaves were collected from the trees in Yap. Minerals and metals were quantified in the leaf samples and regressed onto stem height. Green leaf nitrogen, calcium, manganese, and iron decreased linearly with increased stem height. Senesced leaf carbon, iron, and copper decreased and senesced leaf nitrogen increased with stem height. Nitrogen resorption efficiency decreased with stem height. Phosphorus and potassium resorption efficiencies were not influenced by plant size, but were greater than expected based on available published information. The results indicate leaf nutrient concentrations of this cycad species are directly influenced by plant size, and illuminate the need for adding more cycad species to this research agenda. Plant size should be measured and reported in all cycad reports that include measurements of leaf behavior.

Some aspects of nitrogen, phosphorus, and potassium nutrition of three colonizing beach species

1988 ◽  
Vol 66 (8) ◽  
pp. 1490-1496 ◽  
Author(s):  
Mary Ann Hawke ◽  
M. A. Maun
Keyword(s):  
Poor Response ◽  
Dry Weight ◽  
Plant Size ◽  
Sandy Beaches ◽  
Nutrient Concentrations ◽  
Oenothera Biennis ◽  
Potassium Nutrition ◽  
Cakile Edentula ◽  
Weedy Species ◽  
Phosphorus And Potassium

The culture of three colonizing dune species in hydroponics indicated that nitrogen (N), phosphorus (P), and potassium (K) were essential for high plant productivity. The K requirement of Oenothera biennis was lower than that of Cakile edentula or Corispermum hyssopifolium. The dry weight per plant of O. biennis was greater at higher concentrations of N, P, or K; however, the dry weight per plant of Cor. hyssopifolium was similar at all concentrations except in the complete absence of N, P, or K. Cakile edentula did not grow well under any of the nutrient concentrations, probably because of a poor response to hydroponic solutions. The number of live leaves and leaf area of O. biennis and Cor. hyssopifolium were affected more by a lack of N and P than K. The nutrient requirements of Cakile edentula were substantially higher than those of either O. biennis or Cor. hyssopifolium. It is suggested that the hierarchy in plant size and seed production in field populations may result from variability of available nutrients. Oenothera biennis, a generalist weedy species of farmland, old fields, waste places, and sandy beaches, was less exacting in its requirements of N, P, and K than the two beach specialists, Cakile edentula and Cor. hyssopifolium.

scholarly journals Incident Light and Leaf Age Influence Leaflet Element Concentrations of Cycas micronesica Trees

Horticulturae ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 58 ◽  
Author(s):  
Thomas E. Marler ◽  
Murukesan V. Krishnapillai
Keyword(s):  
Incident Light ◽  
Leaf Age ◽  
Essential Elements ◽  
Nutrient Concentrations ◽  
Sampling Protocols ◽  
Leaf Nutrient Concentrations ◽  
Phosphorus And Potassium ◽  
Shade Leaves ◽  
Sun Leaves ◽  
Nitrogen Phosphorus

The need for improved knowledge on conservation and management of cycad species has generated recent interest in compiling a database on leaf nutrient concentrations. However, the sampling protocols have not been consistent among reports and the influences of some plant and habitat traits on the plasticity of cycad leaf nutrient concentrations has not been adequately determined. We used Cycas micronesica K.D. Hill trees to determine the role of incident light level and leaf age on leaflet content of 11 essential elements. Shade leaves exhibited increased mass-based concentration for nitrogen, phosphorus, and potassium above that of sun leaves. Shade leaves exhibited decreased area-based concentration for all of the macro- and micronutrients below that of sun leaves. Mass-based concentration of nitrogen, phosphorus, and potassium decreased with leaf age, and that of calcium, magnesium, iron, manganese, and zinc increased with leaf age. These findings indicate the relative leaf age and the amount of shade or incident light at the leaf level must be recorded and reported for leaf tissue studies in cycads in order to reduce ambiguity and ensure repeatability.

scholarly journals Leaf nutrients of two Cycas L. species contrast among in situ and ex situ locations

2020 ◽  
Vol 12 (13) ◽  
pp. 16831-16839 ◽  
Author(s):  
Thomas E. Marler ◽  
Anders Lindstrom
Keyword(s):  
Nutrient Dynamics ◽  
Essential Elements ◽  
Tree Canopy ◽  
Ex Situ ◽  
Nutrient Concentrations ◽  
Sampling Protocols ◽  
Leaf Nutrient Concentrations ◽  
Lateral Orientation ◽  
Nutrient Relations

An understanding of leaf nutrient relations is required for tree conservation and horticulture success.  The study of cycad leaf nutrient dynamics has expanded in recent years, but direct comparisons among reports remains equivocal due to varying sampling protocols.  We used Cycas micronesica K.D. Hill and Cycas nongnoochiae K.D. Hill trees to determine the influence on leaf nutrient concentrations of in situ versus ex situ locations and orientation of leaves within the tree canopy.  Nitrogen, phosphorus, and potassium concentrations of leaves from ex situ plants exceeded those from in situ plants, and the differences were not explained by soil nutrient differences.  Calcium concentrations of leaves varied among the site pairs, with differences primarily explained by soil calcium.  Magnesium concentrations of leaves were not different among all location pairs even though soil magnesium concentrations varied among the sites more than any of the other elements.  Differences in leaf macronutrient concentrations among four C. micronesica provenances were minimal when grown in a common garden.  Lateral orientation of leaves did not influence any of the essential elements for either of the species.  These findings indicate that the lateral orientation of cycad leaves does not influence leaf nutrient concentrations, leaf nutrient relations of cycad plants in managed ex situ settings do not align with leaf nutrient relations in habitat, and these differences are not explained by soil nutrition for most elements.  We suggest that leaf nutrient concentrations should be determined in all niche habitats within the geographic range of a cycad species in order to fully understand the leaf physiology of each species. 

scholarly journals Nitrogen and Phosphorus Resorption in Planted Forests Worldwide

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 201 ◽  
Author(s):  
Dalong Jiang ◽  
Qinghong Geng ◽  
Qian Li ◽  
Yiqi Luo ◽  
Jason Vogel ◽  
...  
Keyword(s):  
Nutrient Use Efficiency ◽  
Nutrient Resorption ◽  
Green Leaf ◽  
Mean Annual Precipitation ◽  
Nutrient Concentrations ◽  
Planted Forests ◽  
Climate Zones ◽  
Functional Types ◽  
Precipitation Regimes ◽  
Leaf Nutrient Concentrations

Nutrient resorption from senescing leaves is one of the plants’ essential nutrient conservation strategies. Parameters associated with resorption are important nutrient-cycling constraints for accurate predictions of long-term primary productivity in forest ecosystems. However, we know little about the spatial patterns and drivers of leaf nutrient resorption in planted forests worldwide. By synthesizing results of 146 studies, we explored nitrogen (N) and phosphorus (P) resorption efficiency (NRE and PRE) among climate zones and tree functional types, as well as the factors that play dominant roles in nutrient resorption in plantations globally. Our results showed that the mean NRE and PRE were 58.98% ± 0.53% and 60.21% ± 0.77%, respectively. NRE significantly increased from tropical to boreal zones, while PRE did not significantly differ among climate zones, suggesting differential impacts of climates on NRE and PRE. Plant functional types exert a strong influence on nutrient resorption. Conifer trees had higher PRE than broadleaf trees, reflecting the adaptation of the coniferous trees to oligotrophic habitats. Deciduous trees had lower PRE than evergreen trees that are commonly planted in P-limited low latitudes and have long leaf longevity with high nutrient use efficiency. While non-N-fixing trees had higher NRE than N-fixing trees, the PRE of non-N-fixing trees was lower than that of N-fixing trees, indicating significant impact of the N-fixing ability on the resorption of N and P. Our multivariate regression analyses showed that variations in NRE were mainly regulated by climates (mean annual precipitation and latitude), while variations in PRE were dominantly controlled by green leaf nutrient concentrations (N and P). Our results, in general, suggest that the predicted global warming and changed precipitation regimes may profoundly affect N cycling in planted forests. In addition, green leaf nutrient concentrations may be good indicators for PRE in planted forests.

scholarly journals The C:N:P Stoichiometry of Planted and Natural Larix principis-rupprechtii Stands along Altitudinal Gradients on the Loess Plateau, China

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 363
Author(s):  
Fujing Bo ◽  
Yunxiang Zhang ◽  
Han Y. H. Chen ◽  
Pingan Wang ◽  
Xuming Ren ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Natural Forests ◽  
Resorption Efficiency ◽  
The Loess Plateau ◽  
Planted Forests ◽  
C:N:P Stoichiometry ◽  
Soil C ◽  
Nitrogen Resorption ◽  
N:P Ratios ◽  
Nitrogen Resorption Efficiency

Carbon:nitrogen:phosphorus (C:N:P) stoichiometry plays a critical role in nutrient cycling, biodiversity, and ecosystem functionality. However, our understanding of the responses of C:N:P stoichiometry to elevation and forest management remains elusive. Here we sampled 18 Larix principis-rupprechtii sites along altitudinal gradients (1700-2300 m) on Guandishan Mountain in the Loess Plateau, China. We determined the leaf, litter, and soil C N P contents and C:N:P stoichiometric ratios, as well as nutrient resorption efficiency (NuRE), and diameter at breast height (DBH) increments in both planted and natural stands, and then tested the impacts of elevation and stand origin on these parameters’ management. We found different C:N:P stoichiometry between natural and planted forests. The results revealed that: soil C, N, and N:P ratios, litter C:P and N:P ratios, leaf C:N and N:P ratios increased significantly; however, soil C:N ratios, litter P, leaf N and P, nitrogen resorption efficiency (NRE), and DBH increments decreased significantly with elevation in the planted forests. Soil C,N and N:P ratios, litter C, as well as C:N and C:P ratios increased significantly with elevation in natural forests. The soil N, P and N:P ratios, litter C:P and N:P ratios, leaf C, C:P and N:P ratios, nitrogen resorption efficiency (NRE), phosphorus resorption efficiency (PRE), and DBH increments were, on average, higher in the planted, rather than natural forests. Our results indicated that there was an enhancing P-limitation in both the planted and natural forests, and the plantations were more restricted by P. Moreover, compared to natural forests, plantations converged toward a higher conservative N- and P-use strategy by enhancing resorption efficiencies of internal nutrient cycling and a higher annual growth rate.

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