Fossil evidence for the onset of xeromorphy and scleromorphy in Australian Proteaceae

1998 ◽  
Vol 11 (4) ◽  
pp. 391 ◽  
Author(s):  
Robert S. Hill
Keyword(s):  
Fossil Record ◽  
Leaf Surface ◽  
Late Eocene ◽  
Water Levels ◽  
Morphological Response ◽  
Eastern Australia ◽  
Low Phosphorus ◽  
Dry Conditions ◽  
Leaf Surface Area ◽  
Excessive Water

The morphological response of leaves to low nutrient levels and low phosphorus (scleromorphy) in particular, has become confused in the literature with the response to low water levels (xeromorphy). However, the two can be reconciled to some degree, particularly when it becomes clear that the earliest Proteaceae in the fossil record are scleromorphic, but occurred in very wet climates, where excessive water on the leaf surface was probably a major problem. Unequivocal xeromorphic characters are interpreted as those that increase the boundary layer and thus reduce water loss per unit of leaf surface area without improving water repellancy from the surface. The clearest characters in this regard are the presence of stomata in pits, stomata individually enclosed by raised structures or revolute leaf margins. None of these characters appears prior to the Late Eocene in south-western Australia and the Oligocene in south-eastern Australia, suggesting that xeromorphy arose relatively late, at least in the areas wherefossil deposits occur. A dense covering of trichomes, often interpreted as a xeromorphic response, is here considered to have had the primary function of keeping water off the leaf surface, although it may have been exapted to a xeromorphic function when dry conditions arose. Thus scleromorphy and xeromorphy appear to have arisen at distinctly different times in Australian Proteaceae, with the latter not being a convincingly pre–Late Eocene phenomenon.

scholarly journals Generating and testing hypotheses about the fossil record of insect herbivory with a theoretical ecospace

2021 ◽  
Author(s):  
Sandra R Schachat ◽  
Jonathan L Payne ◽  
C Kevin Boyce ◽  
Conrad C Labandeira
Keyword(s):  
Surface Area ◽  
Fossil Record ◽  
Leaf Surface ◽  
Insect Herbivory ◽  
Fossil Flora ◽  
Insect Damage ◽  
Leaf Surface Area ◽  
Number Of Leaves ◽  
Damage Type ◽  
Damage Types

A typical fossil flora examined for insect herbivory contains a few hundred leaves and a dozen or two insect damage types. Paleontologists employ a wide variety of metrics to assess differences in herbivory among assemblages: damage type diversity, intensity (the proportion of leaves, or of leaf surface area, with insect damage), the evenness of diversity, and comparisons of the evenness and diversity of the flora to the evenness and diversity of damage types. Although the number of metrics calculated is quite large, given the amount of data that is usually available, the study of insect herbivory in the fossil record still lacks a quantitative framework that can be used to distinguish among different causes of increased insect herbivory and to generate null hypotheses of the magnitude of changes in insect herbivory over time. Moreover, estimates of damage type diversity, the most common metric, are generated with inconsistent sampling standardization routines. Here we demonstrate that coverage-based rarefaction yields valid and reliable estimates of damage type diversity that are robust to differences among floral assemblages in the number of leaves examined, average leaf surface area, and the inclusion of plant organs other than leaves such as seeds and axes. We outline the potential of a theoretical ecospace that combines various metrics to distinguish between potential causes of increased herbivory. We close with a discussion of the most appropriate uses of a theoretical ecospace for insect herbivory, with the overlapping damage type diversities of Paleozoic gymnosperms and Cenozoic angiosperms as a brief case study.

Leaves of Eucryphia (Eucryphiaceae) from tertiary sediments in south-eastern Australia

1991 ◽  
Vol 4 (3) ◽  
pp. 481 ◽  
Author(s):  
RS Hill
Keyword(s):  
Leaf Surface ◽  
Late Eocene ◽  
Early Pleistocene ◽  
South Eastern ◽  
Early Tertiary ◽  
Abaxial Leaf Surface ◽  
Extant Species ◽  
Eastern Australia ◽  
Three New Species ◽  
South Eastern Australia

Eucryphia leaves recovered from Tertiary sediments in south-eastern Australia are assigned to three new species, E. falcata (Late Palaeocene, Lake Bungarby), E. microstoma (Early Eocene, Regatta Point) and E. aberensis (Middle to Late Eocene, Loch Aber). Leaves from Early Pleistocene sediments at Regatta Point are re-examined and are considered to be closely related to the extant species, E. lucida and E. milliganii. An examination of the leaf morphology of the fossil and extant species suggests that evolution has taken place, resulting in smaller leaves at higher latitudes and/or altitudes probably in response to climatic change. There is also evidence for an increase in the size and complexity of peltiform cuticular extensions on the abaxial leaf surface from the Early Tertiary to the present, which may be a response to lower water availability or increasing occurrence of frost.

SOOTY MOULD DISEASES OF SOME TREES FROM AURANGABAD DISTRICT, MAHARASHTRA (INDIA)

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
NAVALSINGH J. TODAWAT
Keyword(s):  
Surface Area ◽  
Fungal Pathogens ◽  
Leaf Surface ◽  
Severity Of Disease ◽  
Sooty Mould ◽  
Leaf Surface Area

Sooty mould diseases of Tress from Aurangabad district were surveyed. During the survey of tress, 5 species were found infected by fungal pathogens causing sooty mould diseases. Disease is easily identifiable by the presence of a black, velvety growth covering the leaf surface area. The fungus produces mycelium which is superficial and dark grows on the flowers, leaf, stem and sometime on fruits also. The severity of disease depends on the honeydew secretions by insects. The diseases were found to be caused by 5 species of fungi viz. Capnodium anonae, C. ramosum, Capnodium sp., Meliola bangalorensis and Meliola ranganthii.

INFLUENCE OF GROWTH REGULATORS AND LED IRRADIATORS ON PINE STRAWBERRY ADAPTATION

1970 ◽  
pp. 12-15
Author(s):  
M. G. Markova ◽  
E. N. Somova
Keyword(s):  
Surface Area ◽  
Growth Regulators ◽  
Leaf Surface ◽  
Combined Treatment ◽  
Fragaria X Ananassa ◽  
Leaf Surface Area ◽  
External Conditions ◽  
Light Effects ◽  
Control Version

Work on going through the adaptation stage of rooted micro-stalks comes down to searching for new growth regulators and studying the influence of external conditions, which include, among other things, light effects. The data of 2018-2019 on the effect of growth regulators Siliplant, EcoFus and experimental LED phytoradiators on the adaptation of rooted micro-stalks of garden strawberries (Fragaria x ananassa duch) in vivo are presented. The object of research is rooted micro-stalks of garden strawberries of the Korona variety. It was revealed that, at the adaptation stage of rooted micro-stalks of strawberries, the most effective was the treatment of plants by spraying with Siliplant at a concentration of 1.0 ml/l and the combined treatment with Siliplant and EcoFus at concentrations of 0.5 ml/l: regardless of lighting, the survival rate averaged 99.4 - 99.7%, the leaf surface area increased significantly from 291.85 mm2 to 334.4 mm2. The number of normally developed leaves of strawberry microplants increased significantly after treatment with all preparations from 3.5 to 6.0, 5.8 and 6.5 pcs/plant, and a significant increase in the height of strawberry rosettes was facilitated by treatment with Siliplant and Siliplant together with EcoFus. Regardless of growth regulators, the most effective was the experimental LED phyto-irradiator with a changing spectrum, which contributed to an increase in leaf surface area, height of rosettes and the number of normally developed leaves in strawberry microplants. When illuminated with a flashing phytoradiator, these indicators are lower than in the control version, but not significantly. By the end of the rooting stage, all microplants of garden strawberries corresponded to GOST R 54051-2010.

Falcatifolium (Podocarpaceae) macrofossils from paleogene sediments in south-eastern Australia: a reassessment

1998 ◽  
Vol 11 (6) ◽  
pp. 711 ◽  
Author(s):  
Robert S. Hill ◽  
Leonie J. Scriven
Keyword(s):  
Leaf Morphology ◽  
Middle Eocene ◽  
Late Eocene ◽  
South Eastern ◽  
Early Oligocene ◽  
Extant Species ◽  
Eastern Australia ◽  
South Eastern Australia

A re-investigation of macrofossils previously referred to the extantpodocarpaceous genus Falcatifolium Laubenfels shows thatno records can be sustained. Falcatifolium australisD.R.Greenwood from Middle Eocene sediments in Victoria bears littleresemblance to extant species in the genus and is transferred to the newfossil genus Sigmaphyllum R.S.Hill & L.J.Scriven.Specimens from Early Oligocene sediments in Tasmania previously assigned toFalcatifolium are described as a second species ofSigmaphyllum, S. tasmanensisR.S.Hill & L.J.Scriven, and specimens from mid to late Eocene sediments inTasmania previously assigned to Falcatifolium do notbelong to that genus, although their true generic affinities are uncertain.Dispersed cuticle specimens from Late Eocene–Oligocene sediments inSouth Australia referred to Falcatifolium are notreliable records of the genus and require further investigation. However,Dacrycarpus eocenica D.R.Greenwood, from Middle Eocenesediments in Victoria is transferred to Falcatifolium,and is similar to the extant species F. angustumLaubenfels, which has a leaf morphology unusual for the genus.Falcatifolium eocenica (D.R.Greenwood) R.S.Hill & L.J.Scriven is the only reliable record of the genus in the Australian fossilrecord to date.

Particle size, leaf pubescence and condition of humidity at leaf surfaces are key factors determining the retention of volcanic ash on crop foliage.

2021 ◽  
Author(s):  
Noa Ligot ◽  
Benoît Pereira ◽  
Patrick Bogaert ◽  
Guillaume Lobet ◽  
Pierre Delmelle
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Leaf Surface ◽  
Volcanic Risk ◽  
Chilli Pepper ◽  
Leaf Pubescence ◽  
Leaf Surfaces ◽  
Plant Foliage ◽  
Leaf Surface Area ◽  
Ash Deposit

<p>Volcanic ashfall negatively affects crops, causing major economic losses and jeopardising the livelihood of farmers in developing countries where agriculture is at volcanic risk. Ash on plant foliage reduces the amount of incident light, thereby limiting photosynthesis and plant yield. An excessive ash load may also result in mechanical plant damages, such as defoliation and breakage of the stem and twigs. Characterising crop vulnerability to ashfall is critical to conduct a comprehensive volcanic risk analysis. This is normally done by describing the relationship between the ash deposit thickness and the corresponding reduction in crop yield, i.e. a fragility function. However, ash depth measured on the ground surface is a crude proxy of ash retention on plant foliage as this metrics neglects other factors, such as ash particle size, leaf pubescence and condition of humidity at leaf surfaces, which are likely to influence the amount of ash that stays on leaves.</p><p>Here we report the results of greenhouse experiments in which we measured the percentage of leaf surface area covered by ash particles for one hairy leaf plant (tomato, Solanum lycopersicum L.) and one hairless leaf plant (chilli pepper, Capsicum annuum L.) exposed to simulated ashfalls. We tested six particle size ranges (≤ 90, 90-125, 125-250, 250-500, 500-1000, 1000-2000 µm) and two conditions of humidity at leaf surfaces, i.e. dry and wet. Each treatment consisted of 15 replicates. The tomato and chilli pepper plants exposed to ash were at the seven- and eight-leaf stage, respectively. An ash load of ~570 g m<sup>-2 </sup>was applied to each plant using a homemade ashfall simulator. We estimated the leaf surface area covered by ash from pictures taken before and immediately after the simulated ashfall. The ImageJ software was used for image processing and analysis.</p><p>Our results show that leaf coverage by ash increases with decreasing particle size. Exposure of tomato and chilli pepper to ash ≤ 90 μm always led to ~90% coverage of the leaf surface area. For coarser particles sizes (i.e. between 125 and 500 µm) and dry condition at leaf surfaces, a significantly higher percentage (on average 29 and 16%) of the leaf surface area was covered by ash in the case of tomato compared to chilli pepper, highlighting the influence of leaf pubescence on ash retention. In addition, for particle sizes between 90 and 500 µm, wetting of the leaf surfaces prior to ashfall enhanced the ash cover by 19 ± 5% and 34 ± 11% for tomato and chilli pepper, respectively.</p><p>These findings highlight that ash deposit thickness alone cannot describe the hazard intensity accurately. A thin deposit of fine ash (≤ 90 µm) will likely cover the entire leaf surface area, thereby eliciting a disproportionate effect on plant foliage compared to a thicker but coarser deposit. Similarly, for a same ash depth, leaf pubescence and humid conditions at the leaf surfaces will enhance ash retention, thereby increasing the likelihood of damage. Our study will contribute to improve the reliability of crop fragility functions used in volcanic risk assessment.</p>

scholarly journals The effect of water level on lateral movements of fish between river and off-channel habitats and implications for management

2010 ◽  
Vol 61 (3) ◽  
pp. 271 ◽  
Author(s):  
Jarod Lyon ◽  
Ivor Stuart ◽  
David Ramsey ◽  
Justin O'Mahony
Keyword(s):  
Water Level ◽  
Fish Community ◽  
Life History Strategy ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Main River Channel ◽  
Murray River ◽  
Wetland Biodiversity ◽  
Eastern Australia ◽  
Riverine Wetland

Off-channel habitats, such as wetlands and backwaters, are important for the productivity of river systems and for many species of native fish. This study aimed to investigate the fish community, timing and cues that stimulated movement to and from off-channel habitats in the highly regulated Lake Hume to Lake Mulwala reach of the Murray River, south-eastern Australia. In 2004–05, 193 712 fish were collected moving bi-directionally between a 50-km section of the Murray River and several off-channel habitats. Lateral fish movements approximated water level fluctuations. Generally as water levels rose, fish left the main river channel and moved into newly flooded off-channel habitats; there was bi-directional movement as water levels peaked; on falling levels fish moved back to the permanent riverine habitats. Fish previously classified as ‘wetland specialists’, such as carp gudgeons (Hypseleotris spp.), have a more flexible movement and life-history strategy including riverine habitation. The high degree of lateral movement indicates the importance of habitat connectivity for the small-bodied fish community. Wetlands adjacent to the Murray River are becoming increasingly regulated by small weirs and ensuring lateral fish movement will be important in maintaining riverine-wetland biodiversity.

scholarly journals Growth and productivity of wheat plants under drought in the critical phase of ontogenesis

2021 ◽  
Vol 29 ◽  
pp. 35-40
Author(s):  
O. I. Zhuk ◽  
O.O. Stasik
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Surface Area ◽  
Leaf Surface ◽  
Triticum Aestivum L ◽  
Grain Number ◽  
Plant Weight ◽  
Inhibition Of Growth ◽  
Critical Phase ◽  
Leaf Surface Area

Aim. The goal of this work was to study the effect of drought in the critical phase of ontogenesis on the growth and productivity of breed winter wheat plants (Triticum aestivum L.). Methods. Wheat plants of cultivars Darunok Podillya and Podolyanka were grown under optimal nutrition and well-water conditions until the earing-flowering phase, after that the experimental plants were transferred to drought regime for 8 days, after that the optimal water supply was restored to the end of vegetation. During the experiment, the leaf surface area, the mass of internodes and ear were determined. Ripened plants were analyzed according to the structure of the yield. Results. It was established that the effect of drought in the critical phase of ontogenesis the earing-flowering caused to the decreasing in leaf surface area, mass of internodes, ear, mass and number of grains in the ear and plant, weight of 1000 grains. Conclusions. Water deficit in the soil in the critical phase of earing-flowering led to a decrease in the productive of breed winter wheat plants due to the inhibition of growth of ear, decreasing grain number and the mass of ear and grains. Keywords: Triticum aestivum L., internode, ear, productivity, drought.

scholarly journals Влияние элементов технологии возделывания винограда на урожай и КПД ФАР клона 337 сорта Каберне-Совиньон в условиях Западного предгорно-приморского района Крыма

2019 ◽  
pp. 117-121
Author(s):  
Alexander Dikan ◽  
Domnica Kashirina ◽  
Irina Ryff
Keyword(s):  
Surface Area ◽  
Photosynthetically Active Radiation ◽  
Leaf Surface ◽  
Coastal Region ◽  
Maximum Efficiency ◽  
Cabernet Sauvignon ◽  
Efficiency Coefficient ◽  
Active Radiation ◽  
Strong Linear Correlation ◽  
Leaf Surface Area

Приводятся результаты трехлетних исследований по клону 337 сорта Каберне-Совиньон в Западном предгорно-приморском районе Крыма. Показано влияние различной нагрузки на куст (11, 17 и 22 глазка) и зеленых операций (чеканка побегов, нормирование урожая, удаление листьев в зоне гроздей с восточной стороны) на величину урожая и коэффициент полезного действия (КПД) фотосинтетически активной радиации (ФАР). Установлено, что максимальная величина КПД ФАР была 0,52% при нагрузке на куст в две лозы плодоношения без последующих зеленых операций. Изменение КПД ФАР на 93,4% зависит от изменения площади листовой поверхности куста. Между КПД ФАР и урожаем винограда с куста существует сильная линейная корреляционная связь и регрессионная зависимость. Изменение массы урожая винограда с куста на 99,9% зависит от изменения площади листовой поверхности куста и КПД ФАР. Увеличенная нагрузка до 17-22 глазков при обрезке будет способствовать наиболее рациональному использованию ресурсов продуктивности кустов клона 337 сорта Каберне-Совиньон в Западном предгорно-приморском районе Крыма.The paper summarizes results of a three-year study on clone 337 of ‘Cabernet Sauvignon’ cultivar in the western piedmont-coastal region of Crimea. The paper demonstrates the influence of various bush loads (11, 17 and 22 eyes) and green operations (shoot trimming, harvest regulation, leaf removal in the bunch area on the eastern side) on the yield size and efficiency coefficient of photosynthetically active radiation. It was found that the maximum efficiency of photosynthetically active radiation made 0.52% with the bush load of two fruiting canes without subsequent green operations. The 93.4% variance of the efficiency coefficient of photosynthetically active radiation is dependent on leaf surface area variations of the bush. There is a strong linear correlation and regressional relationship between the efficiency of photosynthetically active radiation and the yield of grapes per bush. The 99.9% increase of the yield per bush weight depends on the change in the leaf surface area of the bush and the efficiency coefficient of photosynthetically active radiation. Increasing the load up to 17-22 buds when pruning will contribute to the most rational use of bush productivity resources of clone 337 of ‘Cabernet Sauvignon’ in the western piedmont-coastal region of Crimea.

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