Nutrients in Senesced Leaves: Keys to the Search for Potential Resorption and Resorption Proficiency

Ecology ◽  
1996 ◽  
Vol 77 (6) ◽  
pp. 1716-1727 ◽  
Author(s):  
Keith T. Killingbeck
Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 261 ◽  
Author(s):  
Jian Deng ◽  
Sha Wang ◽  
Chengjie Ren ◽  
Wei Zhang ◽  
Fazhu Zhao ◽  
...  

Plant nitrogen (N) and phosphorus (P) resorption is an important strategy to conserve N and P in the face of nutrient limitation. However, little is known about the variation of N and P resorption efficiency (NRE and PRE) and their correlation with leaves and soil C:N:P stoichiometry in black locust forests (Robinia pseudoacacia L.) of different ages. In this study, we measured C, N, and P concentrations in soil, green leaves, and senesced leaves from black locust forests of different ages (i.e, 10-, 20-, 30-, 36-, and 45-year-old), and calculated the NRE, PRE, and C:N:P stoichiometry ratios. The NRE and PRE tended to increase and then decrease with stand age, ranging from 46.8% to 57.4% and from 37.4% to 58.5%, with averages of 52.61 and 51.89, respectively. The PRE:NRE decreased with increased stand ages. The C:P and N:P of soil and green leaves increased with stand ages, indicating the increase of P limitation. In the senesced leaves, C:P and N:P were lower than in green leaves and first increased and then decreased with stand age. The PRE was significantly negatively correlated with the C:P and N:P of soil and green leaves. The NRE was significantly correlated with the C concentration of green leaves, P of the senesced leaves, and C:N. Results suggested that the NRE and PRE responded differently to soil and plant nutrients in black locust forests of different ages. In addition, the black locust plantations would alter the conservation and use strategy of nutrients in the ecosystem through a plant-mediated pathway. Future studies should elucidate the central nutrient utilization strategy of black locust in response to a nutrient-poor environment and determine how it is involved in regulating nutrient resorption.


Ecology ◽  
1998 ◽  
Vol 79 (5) ◽  
pp. 1820 ◽  
Author(s):  
Keith T. Killingbeck
Keyword(s):  

2003 ◽  
Vol 19 (4) ◽  
pp. 465-468 ◽  
Author(s):  
José Luis Martínez-Sánchez

In lowland tropical and temperate forests, nitrogen (N) and phosphorus (P) resorption from senesced leaves may reflect a mechanism of conservation of a limiting nutrient (Edwards & Grubb 1982, Killingbeck 1996, Proctor et al. 1989, Scott et al. 1992, Songwe et al. 1997, Vitousek & Sanford 1986). At the ecosystem level it has important implications for element cycling. The nutrients which are resorbed during leaf senescence are directly available for further plant growth, which makes a species less dependent on current nutrient uptake. Nutrients which are not resorbed, however, will be circulated through litterfall in the longer term (Aerts 1996).


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 617c-617
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart

Leaf explants of Nicotiana alata Link and Otto. were surface disinfested and cultured on Murashige and Skoog (MS) medium containing 2.66 μm N6-benzyladenine (BA) to promote shoot proliferation. After 5 weeks, proliferated shoots were removed and remaining callus saved. Callus was inoculated with Agrobacterium tumefaciens encoding a senescence-specific promoter SAG12 cloned from Arabidopsis thaliana fused to a Agrobacterium tumefaciens gene encoding isopentenyl transferase which catalyzes cytokinin synthesis. Following inoculation, the callus was cocultivated for 6 days on BA medium. Selection for transgenics was done on BA medium plus 100 mg Kanamycin and 400 mg Ticarcillin (antibiotics) per liter. Proliferating shoots were rooted on MS medium containing antibiotics. Rooted cuttings were transplanted to soil, acclimated and flowered in the greenhouse. Transgenics were outcrossed to a commercial N. alata hybrid. Seed was germinated in vitro on half-strength MS medium plus antibiotics. Segregation of transgenics to nontransgenics was 1:1. Evaluation of leaf senescence on 5-month-old plants showed 2 to 14 times fewer senesced leaves on the transgenic than the nontransgenic plants.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jinpei Gao ◽  
Quan Li ◽  
Junbo Zhang ◽  
Kunkai Cui ◽  
Zhizhuang Wu ◽  
...  

Nutrient resorption can affect plant growth, litter decomposition, and nutrient cycling. Although the effects of nitrogen (N) and biochar fertilizers on soil nutrient concentrations and plant nutrient uptake have been studied, an understanding of how combined applications of N and biochar affect plant nutrient resorption in plantations is lacking. In this study, we applied N (0, 30, 60, and 90 kg N ha−1 yr−1 defined as N0, N30, N60, and N90, respectively) and biochar (0, 20, and 40 t biochar ha−1 defined as BC0, BC20, and BC40, respectively) to the soil of a Moso bamboo plantation. We investigated the effects of these treatments on N and phosphorus (P) resorption by young and mature bamboo plants, as well as the relationships between nutrient resorption and leaf and soil nutrient concentrations. Young bamboo showed significantly greater foliar N resorption efficiency (NRE) and P resorption efficiency (PRE) than mature bamboo. N addition alone significantly increased the N resorption proficiency (NRP) and P resorption proficiency (PRP) but significantly decreased the NRE and PRE of both young and mature bamboo. In both the N-free and N-addition treatments, biochar amendments significantly reduced the foliar NRE and PRE of young bamboo but had the opposite effect on mature bamboo. Foliar NRE and PRE were significantly negatively correlated with fresh leaf N and P concentrations and soil total P concentration but significantly positively correlated with soil pH. Our findings suggest that N addition inhibits plant nutrient resorption and alters the nutrient-use strategy of young and mature bamboo from “conservative consumption” to “resource spending.” Furthermore, biochar amendment enhanced the negative effect of N addition on nutrient resorption in young bamboo but reduced the negative effect on that of mature bamboo under N-addition treatments. This study provides new insights into the combined effects of N and biochar on the nutrient resorption of Moso bamboo and may assist in improving fertilization strategies in Moso bamboo plantations.


2001 ◽  
Vol 126 (5) ◽  
pp. 523-530 ◽  
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart ◽  
Erik V. Nordheim

Nicotiana alata Link and Otto (Jasmine tobacco) was transformed with an autoregulated senescence-inhibition gene construct PSAG12-IPT encoding isopentenyl transferase via Agrobacterium-mediated transformation. Transformation was confirmed by polymerase chain reaction. Transgenic plants exhibited up to 2- to 4-fold fewer senesced leaves, 29% longer in situ flower life, 26% more shoot dry weight, and a 32% to 50% reduction in flowers per branch. Additionally, transgenics were 28% shorter and had up to 174% more branches, indicative of cytokinin overproduction and a lack of tight autoregulation of PSAG12-IPT. Variation among independent transgenics suggests selection for enhanced PSAG12-IPT is feasible. Our observations of increased branching and in situ flower longevity, as well as reduced plant height and flowers per branch provide new information on PSAG12-IPT and its potential value for biological study and horticultural application.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9915
Author(s):  
Zhen Wang ◽  
Saheed Olaide Jimoh ◽  
Xiliang Li ◽  
Baoming Ji ◽  
Paul C. Struik ◽  
...  

Nutrient resorption from senesced leaves is an important mechanism for nutrient conservation in plants. However, little is known about the effect of grazing on plant nutrient resorption from senesced leaves, especially in semiarid ecosystems. Here, we evaluated the effects of grazing on N and P resorption in the three most dominant grass species in a typical steppe in northern China. We identified the key pathways of grazing-induced effects on N and P resorption efficiency. Grazing increased N and P concentrations in the green leaves of Leymus chinensis and Stipa grandis but not in Cleistogenes squarossa. Both L. chinensis and S. grandis exhibited an increasing trend of leaf N resorption, whereas C. squarrosa recorded a decline in both leaf N and P resorption efficiency under grazing. Structural equation models showed that grazing is the primary driver of the changes in N resorption efficiency of the three dominant grass species. For L. chinensis, the P concentration in green and senesced leaves increased the P resorption efficiency, whereas the senesced leaf P concentration played an important role in the P resorption efficiency of C. squarrosa. Grazing directly drove the change in P resorption efficiency of S. grandis. Our results suggest that large variations in nutrient resorption patterns among plant species depend on leaf nutritional status and nutrient-use strategies under overgrazing, and indicate that overgrazing may have indirect effects on plant-mediated nutrient cycling via inducing shifts in the dominance of the three plant species.


2019 ◽  
Vol 124 (3) ◽  
pp. 471-480 ◽  
Author(s):  
Priyakshee Borpatragohain ◽  
Terry J Rose ◽  
Lei Liu ◽  
Bronwyn J Barkla ◽  
Carolyn A Raymond ◽  
...  

Abstract Background and Aims Sulphur (S) is an essential macronutrient involved in numerous metabolic pathways required for plant growth. Crops of the plant family Brassicaceae require more S compared with other crops for optimum growth and yield, with most S ultimately sequestered in the mature seeds as the storage proteins cruciferin and napin, along with the unique S-rich secondary metabolite glucosinolate (GSL). It is well established that S assimilation primarily takes place in the shoots rather than roots, and that sulphate is the major form in which S is transported and stored in plants. We carried out a developmental S audit to establish the net fluxes of S in two lines of Brassica juncea mustard where seed GSL content differed but resulted in no yield penalty. Methods We quantified S pools (sulphate, GSL and total S) in different organs at multiple growth stages until maturity, which also allowed us to test the hypothesis that leaf S, accumulated as a primary S sink, becomes remobilized as a secondary source to meet the requirements of GSL as the dominant seed S sink. Key Results Maximum plant sulphate accumulation had occurred by floral initiation in both lines, at which time most of the sulphate was found in the leaves, confirming its role as the primary S sink. Up to 52 % of total sulphate accumulated by the low-GSL plants was lost through senesced leaves. In contrast, S from senescing leaves of the high-GSL line was remobilized to other tissues, with GSL accumulating in the seed from commencement of silique filling until maturity. Conclusion We have established that leaf S compounds that accumulated as primary S sinks at early developmental stages in condiment type B. juncea become remobilized as a secondary S source to meet the demand for GSL as the dominant seed S sink at maturity.


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