scholarly journals Presence of N-fixing neighbors increases leaf N and δ13C in Castilleja applegatei, a root hemiparasite

Plant Ecology ◽  
2021 ◽  
Author(s):  
Audrey F. Haynes
Keyword(s):  
Soil Moisture ◽  
Community Structure ◽  
Plant Community ◽  
Parasitic Plants ◽  
Percent Cover ◽  
Root Hemiparasite ◽  
N Limitation ◽  
Mediated Effects ◽  
Use Efficiency ◽  
Leaf N

AbstractParasitic plants are known for their high transpiration rates and low water use efficiency (WUE), which the N-parasitism hypothesis posits is driven by N limitation. Thus, availability of N-fixing hosts may affect parasite’s WUE and in turn impact the surrounding plant community. Here, I investigate how the availability of an N-fixing host affects the root hemiparasite, Castilleja applegatei, and examines host-mediated effects on community structure and soil moisture. I surveyed plant diversity and percent cover and measured soil moisture in 120 1 × 1 m plots within Sagehen Experimental Forest, CA. Fifty percent of the plots included C. applegatei. In a subset of plots, I measured leaf N, C/N, δ13C, and δ15N in C. applegatei and in one N-fixer (Ceanothus prostratus) and two non-N-fixing plants (Artemisia tridentata and Wyethia mollis). In C. applegatei availability of N-fixing hosts corresponded to a significant increase in leaf %N, a distinct δ15N signature, and an increase in δ13C (which typically signifies an increased WUE). The presence of parasites was associated with a marginally significant decrease in WUE in N-fixing neighbors, but had no effect on the two non-N-fixing species. The presence of parasites did not impact diversity, percent cover, or soil moisture. These results broadly support the N-parasitism hypothesis and indicate that host type can affect parasite’s physiology and therefore have the potential to mediate parasite’s effects in the community; however, community-level impacts were not found here.

scholarly journals Nitrogen use efficiency and critical leaf N concentration of Aloe vera in urea and diammonium phosphate amended soil

Heliyon ◽  
2020 ◽  
Vol 6 (12) ◽  
pp. e05718
Author(s):  
Md. Akhter Hossain Chowdhury ◽  
Taslima Sultana ◽  
Md. Arifur Rahman ◽  
Tanzin Chowdhury ◽  
Christian Ebere Enyoh ◽  
...  
Keyword(s):  
Nitrogen Use Efficiency ◽  
Aloe Vera ◽  
Diammonium Phosphate ◽  
Nitrogen Use ◽  
N Concentration ◽  
Leaf N Concentration ◽  
Use Efficiency ◽  
Leaf N ◽  
Amended Soil

Study on Construction of Close-to-Nature Man-Made Plant Landscape Based on Natural Plant Communities: the Case of West Lake Scenic Area in Hangzhou

2012 ◽  
Vol 468-471 ◽  
pp. 2764-2770
Author(s):  
Shan Lu ◽  
Bo Chen ◽  
Shao Qing Hu ◽  
Jing Jing Zhang ◽  
Jun Hao Jiang ◽  
...  
Keyword(s):  
Community Structure ◽  
Plant Community ◽  
Plant Communities ◽  
Vegetation Composition ◽  
Natural Community ◽  
Community Based ◽  
Natural Plant ◽  
West Lake ◽  
Construction Methods ◽  
Landscape Plant

Urban close-to-nature plant community is a sustainable design and construction philosophy of landscape greenbelt planning. However, there is no explicit guide for constructing close-to-nature plant community Based on the analysis of community structure and characteristics of 10 typical natural plant communities in the West Lake Scenic Area in Hangzhou and summary of the features of natural community, as well as the analysis of plant landscape of Hangzhou Huagangguanyu Park to prove that the close-to-nature man-made plant community and natural plant community are interrelated in respect of vegetation composition and community structure, this paper puts forward to the essential construction methods of the close-to-nature landscape community, providing theoretical basis for research and construction of urban close-to-nature landscape plant community in China.

Modulation of photosynthesis and inorganic carbon acquisition in a marine microalga by nitrogen, iron, and light availability

2005 ◽  
Vol 83 (7) ◽  
pp. 917-928 ◽  
Author(s):  
Erica B Young ◽  
John Beardall
Keyword(s):  
Inorganic Carbon ◽  
Dunaliella Tertiolecta ◽  
Initial Slope ◽  
Carbon Concentrating Mechanism ◽  
High Affinity ◽  
N Limitation ◽  
Marine Microalga ◽  
Concentrating Mechanism ◽  
Energy Limitation ◽  
Use Efficiency

The marine microalga Dunaliella tertiolecta Butcher expresses a high affinity for dissolved inorganic carbon (DIC) through a carbon-concentrating mechanism (CCM), known to be influenced by CO2 availability and instantaneous light supply. However, the regulation by light and nutrient supply during growth is less understood, although N and Fe limitation impose an energy limitation by compromising the photosynthetic apparatus. Dunaliella tertiolecta was grown under steady-state conditions of limited light, N, and Fe availability, and the affinity for DIC was measured under saturating light. High affinity DIC uptake capacity was maintained by D. tertiolecta under all growth-limiting conditions, but was modulated in response to the limiting resource. Affinity of photosynthesis for DIC(k0.5) was significantly reduced in cells grown under low light, both in turbidostats and in batch culture (p ≤ 0.03), although cell-normalized Pmax was not significantly affected. In contrast, N and Fe limitation resulted in a significant reduction in cell chlorophyll, Pmax, and maximum photosystem II quantum yield (Fv/Fm), but the affinity for DIC was enhanced with increasing N or Fe stress. While the affinity for DIC improved with increasing N stress (k0.5 < 17.8 µM at µ = 0.27 d–1 versus k0.5 > 26 µM at µ ≥ 0.77 d–1), light use efficiency (α) was impaired under N limitation, suggesting a trade-off between light harvesting capacity and active DIC uptake. Stable C isotope analysis of Fe-limited cells confirmed a lower fractionation by the most Fe-limited cells, consistent with the k0.5 data and more active DIC acquisition (δ13C = –19.56 at µ = 0.27 d–1 cf. δ13C = –26.28 at µ = 0.77 d–1). Assessment of affinity for DIC using k0.5 was supported by the close fit of P versus DIC curves to Michaelis–Menten kinetics; with the high DIC affinity of D. tertiolecta, there was poor resolution in the initial slope of the P versus DIC curve as a parameter of affinity for DIC. Enhanced DIC uptake efficiency under Fe and N limitation may relate to improved resource-use efficiency conferred by CCM activity.Key words: algae, carbon-concentrating mechanism, iron, light, nitrogen, nutrient limitation, photosynthesis.

Water demand and water use efficiency of winter barley in Hungary

2011 ◽  
Vol 59 (1) ◽  
pp. 13-22
Author(s):  
Z. Varga-Haszonits ◽  
E. Enzsölné Gerencsér ◽  
Z. Lantos ◽  
Z. Varga
Keyword(s):  
Soil Moisture ◽  
Water Supply ◽  
Water Use Efficiency ◽  
Water Use ◽  
Potential Evapotranspiration ◽  
Growth Period ◽  
Winter Barley ◽  
Potential Yield ◽  
Yield Data ◽  
Use Efficiency

The temporal and spatial variability of soil moisture, evapotranspiration and water use were investigated for winter barley. Evaluations were carried out on a database containing meteorological and yield data from 15 stations. The spatial distribution of soil moisture, evapotranspiration and water use efficiency (WUE) was evaluated from 1951 to 2000 and the moisture conditions during the growth period of winter barley were investigated. The water supply was found to be favourable, since the average values of soil moisture remained above the lower limit of favourable water content throughout the growth period, except for September–December and May–June. The actual evapotranspiration tended to be close to the potential evapotranspiration, so the water supplies were favourable throughout the vegetation period. The calculated values of WUE showed an increasing trend from 1960 to 1990, but the lower level of agricultural inputs caused a decline after 1990. The average values of WUE varied between 0.87 and 1.09 g/kg in different counties, with higher values in the northern part of the Great Hungarian Plain. The potential yield of winter barley can be calculated from the maximum value of WUE. Except in the cooler northern and western parts of the country, the potential yield of winter barley, based on the water supply, could exceed 10 t/ha.

A computational history and outlook of nitrogen use efficiency and precipitation-optimal fertilisation timings in agriculture

2021 ◽  
Author(s):  
Daniel McKay Flecher ◽  
Siul Ruiz ◽  
Tiago Dias ◽  
Katherine Williams ◽  
Chiara Petroselli ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Nitrogen Uptake ◽  
Nitrogen Use Efficiency ◽  
Nitrogen Efficiency ◽  
Nitrogen Use ◽  
Plant Nitrogen ◽  
Nitrogen Fertilisation ◽  
Plant Nitrogen Uptake ◽  
Use Efficiency ◽  
Rainfall Patterns

&lt;p&gt;Half of the nitrogen applied to arable-fields is lost through several processes linked to soil moisture. Low soil moisture limits nitrogen mobility reducing nitrogen-uptake while wetter conditions can increase nitrogen leaching. Rainfall ultimately governs soil moisture and the fate of nitrogen in soil. However, the interaction between rainfall and nitrogen use efficiency (NUE) remains poorly understood.&lt;/p&gt; &lt;p&gt;We developed a field-scale modelling platform that describes coupled water and nitrogen transport, root growth and uptake, rainfall, the nitrogen-cycle and leaching to assess the NUE of split fertilisations with realistic rainfall patterns. The model was solved for every possible split fertilisation timing in 200+ growing seasons to determine optimal timings. Two previous field trials regarding rainfall and NUE had contrasting results: wetter years have enhanced fertiliser loss and drier years reduced plant nitrogen uptake. By choosing appropriate fertilisation timings in the model we could recreate the two contrasting trends and maintain variability in the data. However, we found by choosing other fertilisation timings we could mitigate the leaching in wetter years. Optimised timings could increase plant nitrogen uptake by up to 35% compared to the mean in dry years. Plant uptake was greatest under drier conditions due to mitigated leaching, but less likely to occur due to low nitrogen mobility. Optimal fertilisation timings varied dramatically depending on the rainfall patterns. Historic and projected rainfall patterns from 1950-2069 were used in the model. We found optimal NUE has a decrease from 2022-2040 due to increased heavy rainfall events and optimal fertilisation timings are later in the season but varied largely on a season-to-season basis.&lt;/p&gt; &lt;p&gt;The results are a step towards achieving improved nitrogen efficiency in agriculture by using the &amp;#8216;at the right time&amp;#8217; agronomic-strategy in the &amp;#8216;4Rs&amp;#8217; of improved nitrogen fertilisation. Our results can help determine nitrogen fertilisation timings in changing climates.&lt;/p&gt;

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