scholarly journals Putative biotic drivers of plant seasonal phenology: herbivory and pathogens as selective forces, with special reference to deciduousness

2021 ◽  
Author(s):  
Rowland Burdon ◽  
Michael Bartlett
Keyword(s):  
Plant Phenology ◽  
Plant Tissues ◽  
Biotic Factors ◽  
Predator Satiation ◽  
Seasonal Timing ◽  
Woody Perennials ◽  
Selective Forces ◽  
Climatic Drivers ◽  
Lock In ◽  
Food Value

Plant phenology is manifested in the seasonal timing of flowering and vegetative processes, but also has ontogenetic aspects. The adaptive basis of seasonal phenology has been considered mainly in terms of climatic drivers. However, some biotic factors as likely evolutionary influences on plants’ phenology appear to have been under-researched. Several specific cases of putative biotic factors driving plant phenology are outlined, involving both herbivores and pathogens. These illustrate the diversity of likely interactions rather than any systematic coverage or review. Emphasis is on woody perennials, in which phenology is often most multi-faceted and complicated by the ontogenetic aspect. The timing and duration of shoot flushing may in at least some cases contribute to defencses against herbivores, largely through brief periods of ‘predator satiation’ when plant tissues have highest food value. However, the complete seasonal leaf fall that characterizes deciduous plants may be a very important defencse against some pathogens. Whether biotic influences drive acquisition or ‘biotic lock-in’ of deciduousness is considered. In one case; of leaf rusts in poplars, countervailing influences of the rusts and climate suggest lock-in. Often, however, biotic and environmental influences likely reinforce each other. Wide re-examination of plant phenology, accommodating the roles of biotic factors and their interplays with environments as additional adaptive drivers, is advocated, towards developing and applying hypotheses that are observationally or experimentally testable.

scholarly journals Putative biotic drivers of plant phenology :with special reference to pathogens and deciduousness

2021 ◽  
Author(s):  
Rowland Burdon ◽  
Michael Bartlett
Keyword(s):  
Plant Phenology ◽  
Plant Tissues ◽  
Biotic Factors ◽  
Predator Satiation ◽  
Seasonal Timing ◽  
Woody Perennials ◽  
Climatic Drivers ◽  
Reproductive Processes ◽  
Food Value

Plant phenology is manifested in the seasonal timing of vegetative and reproductive processes, but also has ontogenetic aspects. The adaptive basis of seasonal phenology has been considered mainly in terms of climatic drivers. However, some biotic factors as likely evolutionary influences on plants’ phenology appear to have been under-researched. Several specific cases of putative biotic factors driving plant phenology are outlined, involving both herbivores and pathogens. These illustrate the diversity of likely interactions rather than any systematic coverage or review. Emphasis is on woody perennials, in which phenology is often most multi-faceted and complicated by the ontogenetic aspect. The complete seasonal leaf fall that characterises deciduous plants may be a very important defence against some pathogens. Whether biotic influences drive acquisition or long-term persistence of deciduousness is considered. In one case; of leaf rusts in poplars, countervailing influences of the rusts and climate suggest persistence. Often, however, biotic and environmental influences likely reinforce each other. The timing and duration of shoot flushing may in at least some cases contribute to defences against herbivores, largely through brief periods of ‘predator satiation’ when plant tissues have highest food value. Wide re-examination of plant phenology, accommodating the roles of biotic factors and their interplays with environments as additional adaptive drivers, is advocated, towards developing and applying hypotheses that are observationally or experimentally testable.

Uptake and accumulation of heavy metals by Typha latifolia in wetlands of the Sudbury, Ontario region

1983 ◽  
Vol 61 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Gregory J. Taylor ◽  
A. A. Crowder
Keyword(s):  
Heavy Metals ◽  
Iron Deficiency ◽  
Typha Latifolia ◽  
Leaf Tissue ◽  
Plant Tissues ◽  
Organic Carbon Content ◽  
Biotic Factors ◽  
Soil Sediment ◽  
Sediment Ph ◽  
Sediment Metal

The accumulation of Cu, Ni, Zn, Fe, Mn, Mg, and Ca in tissues of Typha latifolia along a 76-km transect extending northwest from Sudbury, Ont., was investigated. Despite high levels of Cu and Ni in the soil–sediment material, these metals were largely excluded from aboveground tissues of T. latifolia. Concentrations of Fe in tissues of T. latifolia were unusually low and may reflect induced iron deficiency. The patterns of uptake of all the metals (except Ca) were similar. Roots showed higher concentrations than the rhizomes and aboveground parts and young leaf tissue (leaf bases) showed lower concentrations than older leaf tissue (leaf tips). Concentrations of Zn, Mg, and Ca accumulated in tissues of T. latifolia were not correlated with soil–sediment metal concentrations. Concentrations of Cu and Ni in belowground and reproductive tissues were correlated with soil–sediment concentrations; however, concentrations in the leaves were not. Accumulation of Fe and Mn in all plant tissues was correlated with concentrations in the soil–sediment material. Soil–sediment pH, Eh, and organic carbon content may have affected the uptake of metals by T. latifolia. However, the effects of any of these factors in isolation may have been obscured by the variation in other physical or biotic factors.

scholarly journals SPECULATION CONCERNING SPECIATION IN CORAL REEF FISHES

2018 ◽  
Vol 17 ◽  
pp. 133-139
Author(s):  
J. R. Nursall
Keyword(s):  
Coral Reef ◽  
Marine Environment ◽  
Fish Species ◽  
Abiotic Factors ◽  
Reef Fishes ◽  
Coral Reef Fishes ◽  
Biotic Factors ◽  
Selective Forces ◽  
Space Volume

The relatively constant equatorial marine environment provides a milieu within which biotic factors provide the chief selective forces acting on fish species. Increasing diversity increases evolutionary opportunity by heterotrophic magnification. Niche availability is almost limitless, space (volume) is the ultimate constraint. Abiotic thresholds, e.g., seasonal isotherms, are filter barriers to emigration to higher latitudes. Beyond such thresholds, abiotic, factors become the chief selective forces acting on fish species.

scholarly journals Do Foliar Endophytes Matter in Litter Decomposition?

2020 ◽  
Vol 8 (3) ◽  
pp. 446 ◽  
Author(s):  
Emily R. Wolfe ◽  
Daniel J. Ballhorn
Keyword(s):  
Host Plant ◽  
Litter Decomposition ◽  
Fungal Endophytes ◽  
Plant Tissues ◽  
Biotic Factors ◽  
Decomposition Rates ◽  
Plant Host ◽  
Abiotic And Biotic Factors ◽  
Decomposition Experiments ◽  
Tropical Climates

Litter decomposition rates are affected by a variety of abiotic and biotic factors, including the presence of fungal endophytes in host plant tissues. This review broadly analyzes the findings of 67 studies on the roles of foliar endophytes in litter decomposition, and their effects on decomposition rates. From 29 studies and 1 review, we compiled a comprehensive table of 710 leaf-associated fungal taxa, including the type of tissue these taxa were associated with and isolated from, whether they were reported as endo- or epiphytic, and whether they had reported saprophytic abilities. Aquatic (i.e., in-stream) decomposition studies of endophyte-affected litter were significantly under-represented in the search results (p < 0.0001). Indicator species analyses revealed that different groups of fungal endophytes were significantly associated with cool or tropical climates, as well as specific plant host genera (p < 0.05). Finally, we argue that host plant and endophyte interactions can significantly influence litter decomposition rates and should be considered when interpreting results from both terrestrial and in-stream litter decomposition experiments.

Elucidating climatic controls of polynomial trends in interannual variations of northern ecosystem productivities

2021 ◽  
Author(s):  
Wenxin Zhang ◽  
Hongxiao Jin ◽  
Sadegh Jamali ◽  
Zheng Duan ◽  
Mousong Wu ◽  
...  
Keyword(s):  
Climate Change ◽  
Spatial Patterns ◽  
Plant Phenology ◽  
Ecosystem Productivity ◽  
Polynomial Trend ◽  
Non Linear ◽  
Climatic Drivers ◽  
Polynomial Trends ◽  
Permanent Wetland ◽  
Linear Trends

&lt;p&gt;Rapid warming in northern high latitudes during the past two decades may have profound impacts on the structures and functioning of ecosystems. Understanding how ecosystems respond to climatic change is crucial for the prediction of climate-induced changes in plant phenology and productivity. Here we investigate spatial patterns of polynomial trends in ecosystem productivity for northern (&gt; 30 &amp;#176;N) biomes and their relationships with climatic drivers during 2000&amp;#8211;2018. Based on a moderate resolution (0.05&amp;#176;) of satellite data and climate observations, we quantify polynomial trend types and change rates of ecosystem productivities using plant phenology index (PPI), a proxy of gross primary productivity (GPP), and a polynomial trend identification scheme (Polytrend). We find the yearly-integrated PPI (PPI&lt;sub&gt;INT&lt;/sub&gt;) shows a high degree of agreement with an OCO-2-based solar&amp;#8208;induced chlorophyll fluorescence GPP product (GOSIF-GPP) for distinct spatial patterns of trend types of ecosystem productivities. The averaged slope for linear trends of GPP is found positive across all the biomes, among which deciduous broadleaved and evergreen needle-leaved forests show the highest and lowest rates respectively. The evergreen needle-leaved forests, low shrub, and permanent wetland show linear trends in PPI&lt;sub&gt;INT&lt;/sub&gt; over more than 50% of the covered area and permanent wetland also shows a large fraction of the area with the quadratic and cubic trends. Spatial patterns of linear trends for growing season sum of temperature, precipitation, and photosynthetic active radiation have been quantified. Based on the partial correlations between PPI&lt;sub&gt;INT&lt;/sub&gt; and climate drivers, we found that there is a consistent shift of dominant drivers from temperature or radiation to precipitation across all the biomes except the permeant wetland when the trend type of ecosystem productivity changes from linear to non-linear. This may imply precipitation changes in recent years may determine the linear or non-linear responses of ecosystem productivity to climate change. Our results highlight the importance of understanding how changes in climatic drivers may affect the overall responses of ecosystems productivity. Our findings will facilitate the sustainable management of ecosystems accounting for the resilience of ecosystem productivity and phenology to future climate change.&lt;/p&gt;

scholarly journals Do Foliar Endophytes Matter in Litter Decomposition?

2020 ◽  
Author(s):  
Emily Wolfe ◽  
Daniel Ballhorn
Keyword(s):  
Host Plant ◽  
Litter Decomposition ◽  
Fungal Endophytes ◽  
Plant Tissues ◽  
Biotic Factors ◽  
Decomposition Rates ◽  
Plant Host ◽  
Abiotic And Biotic Factors ◽  
Decomposition Experiments ◽  
Tropical Climates

Litter decomposition rates are affected by a variety of abiotic and biotic factors, including the presence of fungal endophytes in host plant tissues. This review broadly analyzes the findings of 67 studies on the roles of foliar endophytes in litter decomposition, and their effects on decomposition rates. Aquatic (i.e., in-stream) decomposition studies of endophyte-affected litter were significantly under-represented in the search results (P &lt; 0.0001). Indicator species analyses revealed that different groups of fungal endophytes were significantly associated with cool or tropical climates, as well as specific plant host genera (P &lt; 0.05). Finally, we argue that host plant and endophyte interactions can significantly influence litter decomposition rates and should be considered when interpreting results from both terrestrial and in-stream litter decomposition experiments.

Microscopy studies of powdery mildew on summer squash

1991 ◽  
Vol 49 ◽  
pp. 520-521
Author(s):  
John S. Gardner ◽  
W. M. Hess
Keyword(s):  
Powdery Mildew ◽  
Tip Growth ◽  
Hyphal Growth ◽  
Plant Tissues ◽  
Vegetative Hypha ◽  
Powdery Mildews ◽  
Summer Squash ◽  
Conidial Formation ◽  
Polar Tip Growth ◽  
Short Conidiophore

Powdery mildews are characterized by the appearance of spots or patches of a white to grayish, powdery, mildewy growth on plant tissues, entire leaves or other organs. Ervsiphe cichoracearum, the powdery mildew of cucurbits is among the most serious parasites, and the most common. The conidia are formed similar to the process described for Ervsiphe graminis by Cole and Samson. Theconidial chains mature basipetally from a short, conidiophore mother-cell at the base of the fertile hypha which arises holoblastically from the conidiophore. During early development it probably elongates by polar-tip growth like a vegetative hypha. A septum forms just above the conidiophore apex. Additional septa develop in acropetal succession. However, the conidia of E. cichoracearum are more doliform than condia from E. graminis. The purpose of these investigations was to use scanning electron microscopy (SEM) to demonstrate the nature of hyphal growth and conidial formation of E. cichoracearum on field-grown squash leaves.

Localization of acid phosphatases in root cap of rice plant

1991 ◽  
Vol 49 ◽  
pp. 224-225
Author(s):  
Y. R. Chen ◽  
Y. F. Huang ◽  
W. S. Chen
Keyword(s):  
Rice Plant ◽  
Developmental Stages ◽  
Uranyl Acetate ◽  
Root Cap ◽  
Plant Tissues ◽  
Acid Phosphatases ◽  
Root Tips ◽  
Buffer Solution ◽  
Cacodylate Buffer ◽  
Ethanol Series

Acid phosphatases are widely distributed in different tisssues of various plants. Studies on subcellular localization of acid phosphatases show they might be present in cell wall, plasma lemma, mitochondria, plastid, vacuole and nucleus. However, their localization in rice cell varies with developmental stages of cells and plant tissues. In present study, acid phosphatases occurring in root cap are examined.Sliced root tips of ten-day-old rice(Oryza sativa) seedlings were fixed in 0.1M cacodylate buffer containing 2.5% glutaraldehyde for 2h, washed overnight in same buffer solution, incubated in Gomori's solution at 37° C for 90min, post-fixed in OsO4, dehydrated in ethanol series and finally embeded in Spurr's resin. Sections were doubly stained with uranyl acetate and lead citrate, and observed under Hitachi H-600 at 75 KV.

Cryosectioning plant roots prepared by high-pressure freezing

1987 ◽  
Vol 45 ◽  
pp. 662-663
Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold
Keyword(s):  
High Pressure ◽  
Cell Walls ◽  
Plant Tissues ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Vitreous State ◽  
Radial Depth ◽  
Irregular Topography ◽  
Considerable Depth ◽  
Conventional Freezing

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

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