Nitrogen resorption and protein degradation during leaf senescence in Chenopodium album grown in different light and nitrogen conditions

Yuko Yasumura; Kouki Hikosaka; Tadaki Hirose

doi:10.1071/fp06307

Nitrogen resorption and protein degradation during leaf senescence in Chenopodium album grown in different light and nitrogen conditions

Functional Plant Biology ◽

10.1071/fp06307 ◽

2007 ◽

Vol 34 (5) ◽

pp. 409 ◽

Cited By ~ 24

Author(s):

Yuko Yasumura ◽

Kouki Hikosaka ◽

Tadaki Hirose

Keyword(s):

Protein Degradation ◽

Leaf Senescence ◽

Chenopodium Album ◽

Growth Conditions ◽

Sink Strength ◽

Physiological Factors ◽

Nitrogen Resorption ◽

Protein Pool ◽

N Resorption ◽

Leaf N

The extent of nitrogen (N) resorption and the degradability of different protein pools were examined in senescing leaves of an annual herb, Chenopodium album L., grown in two light and N conditions. Both N resorption efficiency (REFF; the proportion of green-leaf N resorbed) and proficiency (RPROF; the level to which leaf N content is reduced by resorption) varied among different growth conditions. During leaf senescence, the majority of soluble and membrane proteins was degraded in all growth conditions. Structural proteins were also highly degradable, implying that no particular protein pool constitutes a non-retranslocatable N pool in the leaf. Leaf carbon/N ratio affected the timing and duration of senescing processes, but it did not regulate the extent of protein degradation or N resorption. Sink–source relationships for N in the plant exerted a more direct influence, depressing N resorption when N sink strength was weakened in the low-light and high-N condition. N resorption was, however, not enhanced in high-light and low-N plants with the strongest N sinks, possibly because it reached an upper limit at some point. We conclude that a combination of several physiological factors determines the extent of N resorption in different growth conditions.

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Timing of Nitrogen Resorption-Related Processes during Fall Senescence in Southern Oak Species

Forest Science ◽

10.1093/forsci/fxy062 ◽

2018 ◽

Vol 65 (3) ◽

pp. 245-249 ◽

Cited By ~ 1

Author(s):

Richard Sample ◽

Benjamin A Babst

Keyword(s):

Leaf Senescence ◽

Limited Resource ◽

Leaf Protein ◽

Future Studies ◽

Nitrogen Resorption ◽

Southern Us ◽

Quercus Species ◽

Chlorophyll Protein ◽

N Resorption ◽

Leaf N

Abstract Oak (Quercus) species are prominent in southern US forests. The ability to recycle nitrogen (N) during dormancy is an important adaptation to conserve a limited resource, but N resorption in southern oaks is not well understood. Leaf protein and chlorophyll are both degraded during senescence to release N that can be stored in stems and roots. We hypothesized that leaf N would decrease soon after degradation of leaf protein and/or chlorophyll. Chlorophyll, protein, and N content were measured in leaves of Q. texana, Q. phellos, and Q. nigra during fall 2016 and 2017, in Arkansas. Degradation of protein, which holds the majority of leaf N, started early, in September, whereas chlorophyll degradation and N export from leaves occurred in late November. The delay between protein degradation and N export indicates that N resorption is drawn out over months in southern oaks, because of an unknown mechanism. Protracted leaf senescence could be due to a physiological or biochemical constraint, or it could be an adaptive trait where fall is typically warm and water-limited, but occasionally wet. Our results lay a foundation for future studies to examine how environmental stress may affect nutrient resorption during leaf senescence in southern oak species.

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Macronutrient Allocation to Leaves and Fruit of Mature, Alternate-bearing Pistachio Trees: Magnitude and Seasonal Patterns at the Whole-canopy Level

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.122.2.267 ◽

1997 ◽

Vol 122 (2) ◽

pp. 267-274 ◽

Cited By ~ 31

Author(s):

G.A. Picchioni ◽

P.H. Brown ◽

S.A. Weinbaum ◽

T.T. Muraoka

Keyword(s):

Leaf Senescence ◽

Nutrient Content ◽

Leaf Biomass ◽

Potential Contribution ◽

Alternate Bearing ◽

Crop Load ◽

Seed Fill ◽

N Resorption ◽

Leaf N ◽

Pistachio Trees

Estimates of leaflet and fruit macronutrient (N, P, K, Ca, and Mg) accumulation and resorption were developed in six (three heavily cropping, on-year and three noncropping, off-year) mature pistachio (Pistacia vera L. `Kerman') trees over three growing seasons during three stages of phenology [the spring growth flush (April to June); seed fill (late June to September); and leaf senescence (September to November)]. Crop load influenced total nutrient content per tree in annual organs (leaves and fruit), the relative allocation of nutrients between leaves and fruit, temporal patterns of nutrient accumulation in annual organs, and the magnitude of net leaf nutrient resorption per tree prior to leaf fall. In off-year trees, macronutrient accumulation in annual organs (leaves) was concentrated during the spring flush of growth. In contrast, significant macronutrient accumulation in annual organs of on-year trees (leaves plus fruit) occurred not only during the spring flush of growth but also during seed fill. Duration and magnitude of macronutrient accumulation were greater in on-year vs. off-year trees. Fruit N and P demand during seed fill was partially met by a net decrease in the N and P contents of the pericarp. These decreases in pericarp nutrient content during seed fill were equivalent to 32% and 26% of embryo accumulation of N and P, respectively. Fruit demand for N, P, and K during the spring flush of “on” years was accompanied by reduced leaf N, P, and K contents per tree. Net leaf N, Ca, and Mg resorption per tree during leaf senescence differed with crop load. Net leaf N resorption was significantly greater in off-year trees than on-year trees. Leaf N resorption presumably represents an important component of the N pool stored in perennial tree parts during dormancy. The greater leaf N resorption following “off” years was a function of greater leaf N concentration and greater leaf biomass per tree. In contrast, net leaf resorption of Ca and Mg was greater in on-year vs. off-year trees. Experimental validation of the magnitude and periodicity of nutrient uptake by mature pistachio trees is needed during the alternate-bearing cycle, especially in light of the potential contribution of current fertilization practices to groundwater contamination.

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High nitrogen resorption efficiency of forest mosses

Annals of Botany ◽

10.1093/aob/mcz199 ◽

2019 ◽

Vol 125 (4) ◽

pp. 557-563 ◽

Cited By ~ 1

Author(s):

Xin Liu ◽

Zhe Wang ◽

Xiaoming Li ◽

Kathrin Rousk ◽

Weikai Bao

Keyword(s):

Nutrient Dynamics ◽

Tracer Experiment ◽

N Cycling ◽

Sink Strength ◽

Resorption Efficiency ◽

Moss Species ◽

Nitrogen Resorption ◽

Temperature And Precipitation ◽

Biogeochemical Models ◽

N Resorption

Abstract Background and Aims Nutrient resorption from senescing tissue is a key mechanism for plants to conserve nutrients, and can affect the nutrient dynamics of ecosystems. Yet, our limited knowledge of nitrogen (N) resorption and release from mosses hampers our understanding of the role of mosses as N sources and, thereby, N cycling in moss-dominated ecosystems. The aims of this study were to estimate N resorption efficiency (NRE) of two moss species, identify the pathways of N release from the mosses and to provide a better understanding of N cycling and budgeting strategies of mosses. Methods The dynamics of N allocation along annual moss segments of two dominant moss species (Actinothuidium hookeri and Hylocomium splendens) were assessed in old-growth fir forests using an in situ15N tracer experiment. Key Results The NRE of A. hookeri and H. splendens was 61 and 52 %, respectively. While the mosses lost 23 and 33 % N from live tissues via leaching, 15 and 14 % of N remained in senesced tissues (>3 years old) in A. hookeri and H. splendens, respectively. Conclusions Both mosses resorbed the majority of their tissue N, but a considerable amount of N was lost from live segments. Our results highlight the crucial role mosses play as N sinks in ecosystems, since N retention (resorbed and sequestered in senescent tissue) outweighed N loss via leaching. However, the sink strength depends on temperature and precipitation, which will change in a future climate. The values for NRE, leaching, etc. estimated here can help improve biogeochemical models aiming to complete N budgets for moss-abundant ecosystems.

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Nitrogen resorption and fractionation during leaf senescence in typical tree species in Japan

Journal of Forestry Research ◽

10.1007/s11676-019-01055-z ◽

2019 ◽

Vol 31 (6) ◽

pp. 2053-2062 ◽

Cited By ~ 4

Author(s):

Ayako Enta ◽

Mika Hayashi ◽

Maximo Larry Lopez Caceres ◽

Lei Fujiyoshi ◽

Toshiro Yamanaka ◽

...

Keyword(s):

Tree Species ◽

Isotope Fractionation ◽

Black Locust ◽

Robinia Pseudoacacia ◽

The Other ◽

Larix Kaempferi ◽

Nitrogen Resorption ◽

The Difference ◽

N Resorption ◽

Leaf N

Abstract In northeastern Japan, an area of high precipitation and mountains, beech (Fagus creanata Blume), larch (Larix kaempferi Lamb.), cedar (Cryptomeria japonica D. Don) and black locust (Robinia pseudoacacia L.) were evaluated for N resorption and N isotope fractionation in pre- and post-abscission leaves in comparison to green leaves. The highest leaf N concentration in summer corresponded to the N-fixing black locust, followed in decreasing order by the deciduous beech and larch and evergreen cedar. On the other hand, the lowest N resorption efficiency corresponded to black locust and the highest to beech, in increasing order by larch and cedar. All tree species returned significant amounts of N before leaf abscission; however, N isotope fractionation during leaf N resorption was only found for beech, with a depleted N isotope value from green to pre-abscission leaf. The most N, however, was resorbed from pre-abscission to post-abscission. This result may indicate that δ15N fractionation took place during N transformation processes, such as protein hydrolysis, when the concentration of free amino acids increased sharply. The difference in the type of amino acid produced by each species could have influenced the N isotope ratio in beech but not in the other tree species. The results of this study showed that it is possible to infer the type and timing of processes relevant to N resorption by analyzing leaf δ15N variation during senescence.

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Ethephon Activates the Transcription of Senescence-Associated Genes and Nitrogen Mobilization in Grapevine Leaves (Vitis vinifera cv. Riesling)

Plants ◽

10.3390/plants10020333 ◽

2021 ◽

Vol 10 (2) ◽

pp. 333

Author(s):

Maximilian Hendgen ◽

Stefan Günther ◽

Sven Schubert ◽

Otmar Löhnertz

Keyword(s):

Vitis Vinifera ◽

Leaf Senescence ◽

Methodological Approach ◽

Leaf Transcriptome ◽

Berry Ripening ◽

Model Plant Arabidopsis Thaliana ◽

N Remobilization ◽

Grapevine Leaves ◽

Nitrogen Mobilization ◽

Leaf N

Nitrogen (N) remobilization in the context of leaf senescence is of considerable importance for the viability of perennial plants. In late-ripening crops, such as Vitis vinifera, it may also affect berry ripening and fruit quality. Numerous studies on the model plant Arabidopsis thaliana have confirmed an involvement of the plant hormone ethylene in the regulation of senescence. However, ethylene research on grapevine was mostly focused on its involvement in berry ripening and stress tolerance until now. To investigate the effect of ethylene on the initiation, regulation, and progress of senescence-dependent N mobilization in grapevine leaves, we treated field-grown Vitis vinifera cv. Riesling vines with 25 mM ethephon at the end of berry ripening. Ethephon induced premature chlorophyll degradation and caused a shift of the leaf transcriptome equivalent to developmental leaf senescence. The upregulated metabolic processes covered the entire N remobilization process chain, altered the amino acid composition in the leaves, and resulted in an average 60% decrease in leaf N. Our findings increase the fundamental knowledge about the initiation and manipulation of leaf N remobilization in perennial woody plants by ethephon. This offers a methodological approach to the targeted induction of senescence and thus to an improvement in the N supply of grapes.

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Identification of Arabidopsis stay-green mutants with a functional ethylene-response pathway

NZGA: Research and Practice Series ◽

10.33584/rps.14.2008.3176 ◽

2010 ◽

Vol 14 ◽

pp. 119-129

Author(s):

R. Shirzadian-Khorramabad ◽

H.C. Jing ◽

J. Hille ◽

P.P. Dijkwel

Keyword(s):

Shelf Life ◽

Leaf Senescence ◽

Plant Hormone ◽

Floral Induction ◽

Growth Conditions ◽

Pleiotropic Effects ◽

Wild Type ◽

Stay Green ◽

Ethylene Response ◽

Determinant Factor

Natural or harvest-induced senescence is a major determinant factor causing crop losses. The plant hormone ethylene is a strong inducer of senescence and decreasing the ethylene response can reduce senescence, albeit often with undesirable pleiotropic effects. We took advantage of ethylene-induced leaf senescence as a tool to screen for late senescence Arabidopsis mutants that still have a functional ethylenesignalling pathway. Sixteen Arabidopsis onset of leaf death (old) mutants were selected that stayed green after treatment with ethylene. While all the mutants responded to ethylene in a triple response assay, ten mutants responded to the treatment in the same way as the wild type. These ten mutants showed limited pleiotropic effects when grown under standard growth conditions but nine mutants flowered slightly later than the wild type. Genetic characterisation of a subset of the mutants identified several independent loci controlling the leaf senescence process. The approach resulted in the isolation of several stay-green mutants with a functional ethylene response pathway. The late senescence mutants show extended leaf longevity and further research may advance the field of pre- or post-harvest senescence technology. The results, moreover, suggest that there is a correlation between senescence and floral induction. Keywords: Senescence, Arabidopsis, ethylene, mutant, shelf life

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Effects of Nitrogen Addition and Reproductive Effort on Nutrient Resorption of a Sand-Fixing Shrub

Frontiers in Plant Science ◽

10.3389/fpls.2020.588865 ◽

2020 ◽

Vol 11 ◽

Author(s):

Lilong Wang ◽

Yulin Li ◽

Yulong Duan ◽

Jie Lian ◽

Yongqing Luo ◽

...

Keyword(s):

Reproductive Effort ◽

Fruit Production ◽

Nutrient Resorption ◽

N Recovery ◽

N Addition ◽

Resorption Efficiency ◽

Temporal Separation ◽

N Resorption ◽

N Resorption Efficiency ◽

Leaf N

Caragana microphylla is a sand-fixing leguminous shrub with strong resistance to drought, cold, and low soil fertility. As a result, it plays an essential role in combating desertification in northern China, but little is known about its nutrient budget. Nutrient resorption is a key process in plant nutrient conservation and has marked ecological implications for plant fitness and ecosystem nutrient cycling. We studied the effects of both nitrogen (N) addition and reproductive effort on leaf N resorption of C. microphylla in a temperate semi-arid sandy land in China. The results showed that sprouting of the early leaves from over-wintered buds employs a strategy for slow returns on nutrient investment with smaller specific leaf area (SLA) and higher N resorption efficiency, whereas the late leaves, which sprout from current-year buds, employ a strategy for quick returns on nutrient investment with higher SLA and lower N resorption efficiency. N addition significantly increased the N resorption efficiency from early leaves while exerting no impact on late leaves, suggesting that the increased N recovery from early leaves is done to sustain the high N demands of late leaves. Reproductive effort did not affect the N resorption from early or late leaves due to the temporal separation between fruit production and leaf senescence. Taken together, our results demonstrate that C. microphylla has evolved different investment strategies for leaf N in early and late leaves to conserve nutrients and facilitate its growth in desertified environments.

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Temperature and leaf area expansion of sugarcane: integration of controlled-environment, field and model studies

Functional Plant Biology ◽

10.1071/pp98042 ◽

1998 ◽

Vol 25 (7) ◽

pp. 819 ◽

Cited By ~ 24

Author(s):

Michael J. Robertson ◽

Graham D. Bonnett ◽

R. Michael Hughes ◽

Russell C. Muchow ◽

James A. Campbell

Keyword(s):

Leaf Area ◽

Leaf Senescence ◽

Leaf Size ◽

Field Studies ◽

Growth Conditions ◽

Thermal Time ◽

Leaf Position ◽

Potential Growth ◽

Leaf Stage ◽

Leaf Appearance

Canopy development is an important determinant of crop radiation interception, and in the absence of stress is mainly driven by temperature. The responses to temperature of the component processes of canopy dynamics in sugarcane: leaf appearance, leaf size, tillering, and leaf senescence, were analysed for the commercial Australian cultivar, Q117. Data were derived under optimal growth conditions from controlled environments, and from irrigated field studies in subtropical and tropical locations. Regression of number of fully-expanded leaves in field-grown plants against cumulative thermal time revealed that the thermal time between the appearance of successive leaves increased as a function of leaf number, such that leaf 1 required 86˚Cd and leaf 40 required 160˚Cd. At any moment, on average there were 3.7 leaves still expanding on the stalks. Functions describing leaf appearance gave acceptable prediction of the time course of leaf appearance taken from independent datasets of field-grown plant and ratoon crops. Leaf size increased with leaf position, with the largest leaves observed at approximately leaf 17 and above. Combining functions describing leaf appearance and leaf size as a function of leaf position allowed estimation of leaf area index (LAI) of main stems in plant and ratoon crops in subtropical and tropical environments. Tiller LAI, derived by difference, accounted for 60–90% of total LAI at the 5- leaf stage, declining to 20–50% at the 15-leaf stage. Plant and ratoon crops were similar in terms of the amount and proportion of tiller LAI. Combining data from all field studies indicated under potential growth conditions, leaf senescence was closely related to leaf production. The functions derived in this study give a basis for simulating canopy dynamics under potential growth conditions in sugarcane, though the extent of genotypic variation for the key parameters and their modification by stress remains to be assessed.

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Inhibition of cardiac proteolysis by colchicine. Selective effects on degradation of protein subclasses

Biochemical Journal ◽

10.1042/bj2100063 ◽

1983 ◽

Vol 210 (1) ◽

pp. 63-71 ◽

Cited By ~ 6

Author(s):

J S Crie ◽

J M Ord ◽

J R Wakeland ◽

K Wildenthal

Keyword(s):

Protein Degradation ◽

Total Protein ◽

Protein Turnover ◽

Branched Chain Amino Acids ◽

Inhibitory Effects ◽

Similar Extent ◽

Specific Effects ◽

Protein Pool ◽

Branched Chain ◽

Mitochondrial Cytochromes

1. The effect of colchicine (2.5 microM) on cardiac protein turnover was tested with foetal mouse hearts in organ culture. 2. Colchicine had no effect on protein synthesis, but inhibited total protein degradation by 12-18%. Lumicolchicine, which lacks colchicine's ability to disaggregate microtubules, but shares its non-specific effects, did not alter protein degradation. 3. The colchicine-induced inhibition of protein degradation was accompanied by significant changes in cardiac lysosomal enzyme activities and distribution. 4. Colchicine inhibited the degradation of organellar proteins, including mitochondrial cytochromes, more than that of cytosolic proteins. 5. Colchicine decreased the rate of myosin degradation and the rate of proteolysis of the total protein pool to a similar extent. Since the regulation of myosin degradation does not involve lysosomes, this suggests that colchicine affects non-lysosomal as well as lysosomal pathways. 6. Release of branched-chain amino acids from colchicine-treated hearts was disproportionately decreased, suggesting that colchicine increased their metabolism. 7. It is concluded that colchicine, via its actions on microtubules, exerts important inhibitory effects on cardiac proteolysis. Colchicine is especially inhibitory to the degradation of organellar proteins, including mitochondrial cytochromes. Its inhibitory effects may be mediated in part via lysosomal mechanisms, but non-lysosomal mechanisms are probably involved as well.

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