scholarly journals Convergence in leaf size versus twig leaf area scaling: do plants optimize leaf area partitioning?

2016 ◽  
Vol 119 (3) ◽  
pp. 447-456 ◽  
Author(s):  
Duncan D. Smith ◽  
John S. Sperry ◽  
Frederick R. Adler

Background and Aims Corner’s rule states that thicker twigs bear larger leaves. The exact nature of this relationship and why it should occur has been the subject of numerous studies. It is obvious that thicker twigs should support greater total leaf area (Atwig) for hydraulical and mechanical reasons. But it is not obvious why mean leaf size (A-) should scale positively with Atwig. We asked what this scaling relationship is within species and how variable it is across species. We then developed a model to explain why these relationships exist. Methods To minimize potential sources of variability, we compared twig properties from six co-occurring and functionally similar species: Acer grandidentatum, Amelanchier alnifolia, Betula occidentalis, Cornus sericea, Populus fremontii and Symphoricarpos oreophilus. We modelled the economics of leaf display, weighing the benefit from light absorption against the cost of leaf tissue, to predict the optimal A- :Atwig combinations under different canopy openings. Key Results We observed a common A- by Atwig exponent of 0.6, meaning that A -and leaf number on twigs increased in a specific coordination. Common scaling exponents were not supported for relationships between any other measured twig properties. The model consistently predicted positive A- by Atwig scaling when twigs optimally filled canopy openings. The observed 0·6 exponent was predicted when self-shading decreased with larger canopy opening. Conclusions Our results suggest Corner’s rule may be better understood when recast as positive A- by Atwig scaling. Our model provides a tentative explanation of observed A- by Atwig scaling and suggests different scaling may exist in different environments.

2007 ◽  
Vol 274 (1629) ◽  
pp. 3184-3184 ◽  
Author(s):  
Rubén Milla ◽  
Peter B. Reich

Correction for ‘The scaling of leaf area and mass: the cost of light interception increases with leaf size’ by Rubén Milla and Peter B. Reich (Proc. R. Soc. B 274 , 2109–2114. (doi: 10.1098/rspb.2007.0417 )). The following equation contains typographical errors that has no consequence for any other equation or result in the above paper.


2021 ◽  
Author(s):  
◽  
Benjamin Magana-Rodriguez

<p>The current crisis in loss of biodiversity requires rapid action. Knowledge of species' distribution patterns across scales is of high importance in determining their current status. However, species display many different distribution patterns on multiple scales. A positive relationship between regional (broad-scale) distribution and local abundance (fine-scale) of species is almost a constant pattern in macroecology. Nevertheless interspecific relationships typically contain much scatter. For example, species that possess high local abundance and narrow ranges, or species that are widespread, but locally rare. One way to describe these spatial features of distribution patterns is by analysing the scaling properties of occupancy (e.g., aggregation) in combination with knowledge of the processes that are generating the specific spatial pattern (e.g., reproduction, dispersal, and colonisation). The main goal of my research was to investigate if distribution patterns correlate with plant life-history traits across multiple scales. First, I compared the performance of five empirical models for their ability to describe the scaling relationship of occupancy in two datasets from Molesworth Station, New Zealand. Secondly, I analysed the association between spatial patterns and life history traits at two spatial scales in an assemblage of 46 grassland species in Molesworth Station. The spatial arrangement was quantified using the parameter k from the Negative Binomial Distribution (NBD). Finally, I investigated the same association between spatial patterns and life-history traits across local, regional and national scales, focusing in one of the most diverse families of plant species in New Zealand, the Veronica sect. Hebe (Plantaginaceae). The spatial arrangement was investigated using the mass fractal dimension. Cross-species correlations and phylogenetically independent contrasts were used to investigate the relationships between plant life-history traits and spatial patterns on both data bases. There was no superior occupancy-area model overall for describing the scaling relationship, however the results showed that a variety of occupancy-area models can be fit to different data sets at diverse spatial scales using nonlinear regression. Additionally, here I showed that it is possible to deduce and extrapolate information on occupancy at fine scales from coarse-scale data. For the 46 plantassemblage in Molesworth Station, Specific leaf area (SLA) exhibits a positive association with aggregation in cross-species analysis, while leaf area showed a negative association, and dispersule mass a positive correlation with degree of aggregation in phylogenetic contrast analysis at a local-scale (20 × 20 m resolution). Plant height was the only life-history trait that was associated with degree of aggregation at a regional-scale (100 × 60 mresolution). For the Veronica sect. Hebe dataset, leaf area showed a positive correlation with aggregation while specific leaf area showed a negative correlation with aggregation at a fine local-scale (2.5-60 m resolution). Inflorescence length, breeding system and leaf area showed a negative correlation with degree of aggregation at a regional-scale (2.5-20 km resolution). Height was positively associated with aggregation at national-scale (20-100 km resolution). Although life-history traits showed low predictive ability in explaining aggregation throughout this thesis, there was a general pattern about which processes and traits were important at different scales. At local scales traits related to dispersal and completion such as SLA , leaf area, dispersule mass and the presence of structures in seeds for dispersal, were important; while at regional scales traits related to reproduction such as breeding system, inflorescence length and traits related to dispersal (seed mass) were significant. At national scales only plant height was important in predicting aggregation. Here, it was illustrated how the parameters of these scaling models capture an important aspect of spatial pattern that can be related to other macroecological relationships and the life-history traits of species. This study shows that when several scales of analysis are considered, we can improve our understanding about the factors that are related to species' distribution patterns.</p>


2020 ◽  
Author(s):  
Dejin Xie ◽  
Lingyan Chen ◽  
Chengcheng Zhou ◽  
Muhammad Waqqas Khan Tarin ◽  
Deming Yang ◽  
...  

Abstract Background Sarcandra glabra is an evergreen and traditional Chinese herb, having medicinal significance as anti-oxidant, anti-bacterial, anti-inflammatory, and anti-tumor. Recently, China has initiated to establish cultivation of this plant in greenhouse under artificial light-emitting diodes (LED). However, little is known regarding the effects of the different LED lights on plant growth, accumulation pattern of secondary metabolites, and the molecular mechanism of Sarcandra glabra. Results Compared to white light (WL), the red light (RL) increased the height and decreased the stem diameter and leaf area, while blue light (BL) suppressed the height and leaf area. According to our transcriptome profiling, some differentially expressed genes (DEGs) were enriched in the phenylpropanoid biosynthesis. We identified 46 unigenes encoding for almost all known enzymes involved in phenylpropanoid biosynthesis, while the expression level of RNA-seq and qPCR were largely consistent. Meanwhile, we found 53 unigenes encoding R2R3-MYB proteins and 53 unigenes encoding bHLH proteins that several of them were related to flavonoids biosynthesis. Based on metabolomic profiling, a total of 454 metabolites were detected and the distribution of chemicals varied significantly. While flavonoids, phenolic acids, and tannins were mainly located in leaves; Organic acids, lignans and coumarins, and terpenoids were much more abundant in WG (root tissue under WL). Meanwhile, the yields of most flavonoids from BY (leaf tissue under BL) and the synthesis of primarily targeted compounds was lower than in WY (leaf tissue under WL) and RY (leaf tissue under RL). Instead, the leaves grown under RL exhibited a greater production of bioactive phytochemicals such as esculetin, fraxetin, esculin, and scopoletin. Conclusion These results provide further insight into the molecular mechanism of metabolites accumulation patterns in S. glabra under different light conditions, enabling the development of optimum breeding conditions for this plant.


1995 ◽  
Vol 43 (2) ◽  
pp. 247-260
Author(s):  
H. Biemond

In a series of greenhouse and field trials, spinach cv. Trias plants were supplied with different amounts of N fertilizer in various split applications. Rates of leaf emergence and expansion were recorded, as well as final leaf size. The rate of leaf appearance varied between 0.16 and 0.57/day across experiments, but was hardly affected by N treatment. The rate of leaf expansion and mature leaf area increased with leaf number, reaching maximum values at leaf pair 3+4 or 5+6 and decreasing subsequently. Both characteristics were positively correlated with N supply. The duration of expansion was not influenced by N treatments and varied between 15 and 30 days in most experiments. The rate of leaf expansion was the main factor determining mature leaf size. Specific leaf area over all green leaves slowly decreased with time in most experiments and was around 300 cmsuperscript 2/g. As the differences in the number of leaves were small, the differences in total green leaf area per plant resulted from differences in the areas of individual mature leaves.


1958 ◽  
Vol 51 (3) ◽  
pp. 347-352 ◽  
Author(s):  
R. H. M. Langer

1. Swards of S. 48 timothy and S. 215 meadow fescue growing alone or together were sampled at intervals of 3 weeks throughout the season. The number and weight of leaves, stems and ears were determined, and leaf area was estimated.2. Despite high rainfall, the total number of tillers in both species declined from the beginning of the experiment until early July, but increased again from then onwards until the original complement had been approximately restored. The number of leaves failed to show a corresponding increase in the autumn because each tiller carried fewer leaves than earlier in the year.3. In the spring total dry weight increased more rapidly in meadow fescue than in timothy which in turn out-yielded meadow fescue later in the season. Both species attained their greatest dry weight soon after ear emergence, a period which was marked by considerable crop growth and relative growth rates.4. Leaf area index reached a maximum before total dry weight had increased to its highest level, but then declined in both species. Meadow fescue differed from timothy by producing a second crop of foliage after the summer with a leaf area index of about 7. This second rise appeared to be due mainly to increased leaf size in contrast to timothy whose leaves became progressively smaller towards the end of the season.5. The differences in growth between the species discussed with reference to their dates of ear emergence which in this experiment differed by about 6 weeks.


1998 ◽  
Vol 25 (7) ◽  
pp. 819 ◽  
Author(s):  
Michael J. Robertson ◽  
Graham D. Bonnett ◽  
R. Michael Hughes ◽  
Russell C. Muchow ◽  
James A. Campbell

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.


2020 ◽  
Author(s):  
Dejin Xie ◽  
Lingyan Chen ◽  
Chengcheng Zhou ◽  
Muhammad Waqqas Khan Tarin ◽  
Deming Yang ◽  
...  

Abstract Background: Sarcandra glabra is an evergreen and traditional Chinese herb with anti-oxidant, anti-bacterial, anti-inflammatory, and anti-tumor effects. Light is one of the most influential factor affecting the growth and quality of herbs. In recent times, the introduction of Light Emission Diode (LED) technology has been widely used for plants in greenhouse. However, the impact of such lights on plant growth and the regulatory mechanism of phenylpropanoid-derived compounds in S. glabra remain unclear. Results: The red LED light (RL) substantially increased the plant height and decreased the stem diameter and leaf area relative to the white LED light (WL), while the blue LED light (BL) significantly reduced the height and leaf area of S. glabra. According to transcriptomic profiling, 861, 378, 47, 10,033, 7917, and 6379 differentially expressed genes (DEGs) were identified among the groups of leaf tissue under BL (BY) vs. leaf tissue under RL (RY), BY vs. leaf tissue under WL (WY), RY vs. WY, root tissue under WL (WG) vs. WY, stem tissue under WL (WJ) vs. WG, and WJ vs. WY, respectively. We identified 46 genes encoding for almost all known enzymes involved in phenylpropanoid biosynthesis, e.g., phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), and flavonol synthase (FLS). We found 53 genes encoding R2R3-MYB proteins and bHLH proteins, respectively, where several were related to flavonoids biosynthesis. A total of 454 metabolites were identified based on metabolomic profiling, of which 44, 87, and 296 compounds were differentially produced in WY vs. RY, WY vs. BY, and WY vs. WG. In BY there was a substantial reduction in the production of esculetin, caffeic acid, isofraxidin, and fraxidin, while the yields of quercitrin and kaempferol were significantly up-regulated. In RY, the contents of cryptochlorogenic acid, cinnamic acid, and kaempferol decreased significantly. Besides, in WG, the production of metabolites (e.g. chlorogenic acid, cryptochlorogenic acid, and scopolin) declined, while their yields increased significantly (e.g. esculetin, fraxetin, isofraxidin, and fraxidin).Conclusion: These results provide further insight into the regulatory mechanism of accumulation patterns of phenylpropanoid-derived compounds in S. glabra under various light conditions, allowing optimum breeding conditions to be developed for this plant.


1980 ◽  
Vol 7 (4) ◽  
pp. 363 ◽  
Author(s):  
PJM Sale ◽  
TF Neales

Net carbon exchange over 24-h cycles was measured in well watered pineapple plants, using a 'minicrop' in field assimilation chambers and single leaves in a growth cabinet. Whole plants under natural light and a standard 30°C day/15°C night regime showed crassulacean acid metabolism, nearly all assimilation occurring in the dark period, with a net efflux of CO2 in the day. Assimilation, as measured by both CO2 exchange and changes in titratable acidity in the leaf tissue, was markedly dependent on the total photosynthetically active radiation incident in the previous photoperiod. The molar ratio of the maximum acidity change to maximum net nocturnal CO2 influx was 1.8 : 1. The rate of deacidification depended on the irradiance in the current photoperiod. Efflux in the photoperiod was largely independent of irradiance, but was greater at very low irradiances. Maximum rates of CO2 assimilation in the minicrop were about 15 ng cm-2 (leaf area) s-1 in the dark at the standard temperature regime, and 22 ng-2 s-1 when photoperiod assimilation was induced by a 20°C day/30°C night regime. Similar rates were recorded in the single-leaf experiments, and are higher than those previously found for pineapple. Over a 24-h period, mean rates of about 6 ng cm-2 (leaf area) s-1 were recorded, in good agreement with measured dry weight changes over an extended period. These data help to explain earlier discrepancies in the literature between measured rates of CO2 assimilation and of crop growth rates in pineapples.


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