senSCOPE: Modeling mixed canopies combining green and brown senesced leaves. Evaluation in a Mediterranean Grassland

2021 ◽  
Vol 257 ◽  
pp. 112352
Author(s):  
Javier Pacheco-Labrador ◽  
Tarek S. El-Madany ◽  
Christiaan van der Tol ◽  
M. Pilar Martin ◽  
Rosario Gonzalez-Cascon ◽  
...  
Keyword(s):  
Senesced Leaves

scholarly journals Nitrogen and Phosphorus Resorption in Relation to Nutrition Limitation along the Chronosequence of Black Locust (Robinia pseudoacacia L.) Plantation

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 261 ◽  
Author(s):  
Jian Deng ◽  
Sha Wang ◽  
Chengjie Ren ◽  
Wei Zhang ◽  
Fazhu Zhao ◽  
...  
Keyword(s):  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Nutrient Utilization ◽  
Stand Age ◽  
Nitrogen And Phosphorus ◽  
C:N:P Stoichiometry ◽  
Green Leaves ◽  
Different Ages ◽  
Robinia Pseudoacacia L ◽  
Senesced Leaves

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.

Nutrients in Senesced Leaves: Reply

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

Nitrogen and phosphorus resorption in trees of a neotropical rain forest

2003 ◽  
Vol 19 (4) ◽  
pp. 465-468 ◽  
Author(s):  
José Luis Martínez-Sánchez
Keyword(s):  
Plant Growth ◽  
Nutrient Uptake ◽  
Leaf Senescence ◽  
Rain Forest ◽  
Nitrogen And Phosphorus ◽  
Element Cycling ◽  
Limiting Nutrient ◽  
Ecosystem Level ◽  
Neotropical Rain Forest ◽  
Senesced Leaves

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).

scholarly journals Transformation of Nicotiana alata Link and Otto. with an Autoregulatory Senescence-inhibitor Gene Construct

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 617c-617
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Leaf Explants ◽  
Shoot Proliferation ◽  
Nicotiana Alata ◽  
Ms Medium ◽  
Gene Encoding ◽  
Half Strength ◽  
Cytokinin Synthesis ◽  
Senesced Leaves

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.

scholarly journals Response of Nicotiana alata to Insertion of an Autoregulated Senescence- inhibition Gene

2001 ◽  
Vol 126 (5) ◽  
pp. 523-530 ◽  
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart ◽  
Erik V. Nordheim
Keyword(s):  
Dry Weight ◽  
Biological Study ◽  
Nicotiana Alata ◽  
Isopentenyl Transferase ◽  
Shoot Dry Weight ◽  
New Information ◽  
Polymerase Chain ◽  
Selection For ◽  
Senesced Leaves

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.

scholarly journals Different responses of plant N and P resorption to overgrazing in three dominant species in a typical steppe of Inner Mongolia, China

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9915
Author(s):  
Zhen Wang ◽  
Saheed Olaide Jimoh ◽  
Xiliang Li ◽  
Baoming Ji ◽  
Paul C. Struik ◽  
...  
Keyword(s):  
Plant Species ◽  
Nutrient Resorption ◽  
Grass Species ◽  
Resorption Efficiency ◽  
Typical Steppe ◽  
P Concentration ◽  
N Resorption ◽  
Senesced Leaves ◽  
Dominant Grass ◽  
Leaf N

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.

scholarly journals Remobilization and fate of sulphur in mustard

2019 ◽  
Vol 124 (3) ◽  
pp. 471-480 ◽  
Author(s):  
Priyakshee Borpatragohain ◽  
Terry J Rose ◽  
Lei Liu ◽  
Bronwyn J Barkla ◽  
Carolyn A Raymond ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Storage Proteins ◽  
Growth And Yield ◽  
Growth Stages ◽  
Secondary Source ◽  
Early Developmental ◽  
Mature Seeds ◽  
Senesced Leaves ◽  
Net Fluxes ◽  
Yield Penalty

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.

The effects of copper and nitrogen supply on the retranslocation of copper in four cultivars of wheat

1978 ◽  
Vol 29 (5) ◽  
pp. 925 ◽  
Author(s):  
J Hill ◽  
AD Robson ◽  
JF Loneragan
Keyword(s):  
Grain Yield ◽  
Copper Content ◽  
Copper Deficiency ◽  
High Nitrogen ◽  
Positive Interaction ◽  
High Copper ◽  
Large Numbers ◽  
Low Concentrations ◽  
Senesced Leaves ◽  
Low Nitrogen

The retranslocation of copper and nitrogen was studied in four cultivars of wheat grown in pots of a copper-deficient sand from Lancelin, W.A. Plants were grown at two levels of nitrogen and three levels of copper, and harvested three times during growth and at maturity. Plants grown at low copper were severely copper-deficient and yielded no grain. At low nitrogen, plants at marginal copper gave similar grain yields to plants at high copper. Application of high nitrogen at marginal copper either had little effect or depressed grain yield. Application of high nitrogen at high copper gave a strong positive interaction producing maximal grain yield in each cultivar. Low copper supply delayed yellowing and the decline in copper and nitrogen content of the oldest leaf of each cultivar. Application of high nitrogen further delayed yellowing of the oldest leaf and loss of its copper and nitrogen. Probably the copper content of the oldest leaf does not decline until the leaf begins to senesce. Senesced leaves retain low concentrations of copper and nitrogen. It is suggested that at marginal copper, copper retention by senesced vegetation limits the retranslocation of copper from vegetation to grain. Susceptibility to copper deficiency differed markedly with stage of growth and with cultivar. At marginal copper and high nitrogen, copper deficiency almost eliminated the grain yield of Argentine IX, but had relatively small effects on Gamenya, Olympic, and Petit Rojo. The higher susceptibility of grain production in Argentine IX to copper deficiency was not related to its copper content in whole tops or to its grain protein concentration. The susceptibility may have resulted from the ability of this cultivar to form large numbers of tillers which competed with the developing grain for retranslocated copper.

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