The nymphal stage of Cardiaspina densitexta (Homoptera : Psyllidae) on leaves of Eucalyptus fasciculosa

1970 ◽  
Vol 18 (3) ◽  
pp. 273 ◽  
Author(s):  
TCR White
Keyword(s):  
Leaf Tissue ◽  
High Light Intensity ◽  
Soluble Nitrogen ◽  
Nymphal Stage ◽  
Feeding Site ◽  
Mature Leaves ◽  
The North ◽  
Close Proximity ◽  
Shade Leaves ◽  
Sun Leaves

First-instar nymphs of C. densitexta crawl freely from leaf to leaf on the plant, tending to disperse from overcrowded leaves; some are carried from one tree to another by wind. The lower side of the basal end of mature leaves is the favoured site for settling. Survival and rate of growth in both winter and summer are greater on the north than on the south side of trees. In the laboratory, nymphs can be successfully reared on disks cut from E, fasciculosa leaves and floated on distilled water. Under high light intensity the initial favourability of sun leaves over shade leaves is quickly lost, but disks from old leaves continue to be less favourable than those from mature leaves. Mortality is much greater on leaf tissue exposed to dim light, and disks of sun leaves are then less favourable than those of shade leaves. Isolated individual nymphs have a lower chance of survival and grow more slowly than when there are several nymphs in close proximity. The feeding of nymphs causes discoloration and eventual death of the leaf tissue immediately surrounding the feeding site, and there is, possibly, a secondary systemic toxic effect on the host. These results seem to support the hypothesis that the phloem sap of the host plant-and specifically its soluble nitrogen content is, for most of the time, an inadequate source of food for the nymphs.

Ultrastructure and Senescence in an Achloroplastic Mutant of Hordeum vulgare L. cv. Dyan

1992 ◽  
Vol 50 (1) ◽  
pp. 844-845
Author(s):  
R.H.M. Cross ◽  
C.E.J. Botha ◽  
A.K. Cowan ◽  
B.J. Hartley
Keyword(s):  
Cell Wall ◽  
Hordeum Vulgare ◽  
Leaf Tissue ◽  
Ultrastructural Changes ◽  
Hordeum Vulgare L ◽  
Mesophyll Cells ◽  
Lethal Mutant ◽  
Cytoplasmic Matrix ◽  
Close Proximity ◽  
Pinocytotic Vesicles

Senescence is an ordered degenerative process leading to death of individual cells, organs and organisms. The detection of a conditional lethal mutant (achloroplastic) of Hordeum vulgare has enabled us to investigate ultrastructural changes occurring in leaf tissue during foliar senescence.Examination of the tonoplast structure in six and 14 day-old mutant tissue revealed a progressive degeneration and disappearance of the membrane, apparently starting by day six in the vicinity of the mitochondria associated with the degenerating proplastid (Fig. 1.) where neither of the plastid membrane leaflets is evident (arrows, Fig. 1.). At this stage there was evidence that the mitochondrial membranes were undergoing retrogressive changes, coupled with disorganization of cristae (Fig. 2.). Proplastids (P) lack definitive prolamellar bodies. The cytoplasmic matrix is largely agranular, with few endoplasmic reticulum (ER) cisternae or polyribosomal aggregates. Interestingly, large numbers of actively-budding dictysomes, associated with pinocytotic vesicles, were observed in close proximity to the plasmalemma of mesophyll cells (Fig. 3.). By day 14 however, mesophyll cells showed almost complete breakdown of subcellular organelle structure (Fig. 4.), and further evidence for the breakdown of the tonoplast. The final stage of senescence is characterized by the solubilization of the cell wall due to expression and activity of polygalacturonase and/or cellulose. The presence of dictyosomes with associated pinocytotic vesicles formed from the mature face, in close proximity to both the plasmalemma and the cell wall, would appear to support the model proposed by Christopherson for the secretion of cellulase. This pathway of synthesis is typical for secretory glycoproteins.

scholarly journals The role of JrPPOs in the browning of walnut explants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shugang Zhao ◽  
Hongxia Wang ◽  
Kai Liu ◽  
Linqing Li ◽  
Jinbing Yang ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Production Efficiency ◽  
Phenolic Content ◽  
Leaf Tissue ◽  
Limiting Factor ◽  
Mature Leaves ◽  
Survival Percentage ◽  
Highly Active ◽  
Young Leaves

Abstract Background Tissue culture is an effective method for the rapid breeding of seedlings and improving production efficiency, but explant browning is a key limiting factor of walnut tissue culture. Specifically, the polymerization of PPO-derived quinones that cause explant browning of walnut is not well understood. This study investigated explants of ‘Zanmei’ walnut shoot apices cultured in agar (A) or vermiculite (V) media, and the survival percentage, changes in phenolic content, POD and PPO activity, and JrPPO expression in explants were studied to determine the role of PPO in the browning of walnut explants. Results The results showed that the V media greatly reduced the death rate of explants, and 89.9 and 38.7% of the explants cultured in V media and A media survived, respectively. Compared with that of explants at 0 h, the PPO of explants cultured in A was highly active throughout the culture, but activity in those cultured in V remained low. The phenolic level of explants cultured in A increased significantly at 72 h but subsequently declined, and the content in the explants cultured in V increased to a high level only at 144 h. The POD in explants cultured in V showed high activity that did not cause browning. Gene expression assays showed that the expression of JrPPO1 was downregulated in explants cultured in both A and V. However, the expression of JrPPO2 was upregulated in explants cultured in A throughout the culture and upregulated in V at 144 h. JrPPO expression analyses in different tissues showed that JrPPO1 was highly expressed in stems, young leaves, mature leaves, catkins, pistils, and hulls, and JrPPO2 was highly expressed in mature leaves and pistils. Moreover, browning assays showed that both explants in A and leaf tissue exhibited high JrPPO2 activity. Conclusion The rapid increase in phenolic content caused the browning and death of explants. V media delayed the rapid accumulation of phenolic compounds in walnut explants in the short term, which significantly decreased explants mortality. The results suggest that JrPPO2 plays a key role in the oxidation of phenols in explants after branch injury.

scholarly journals A Series of Humanly-Fashioned Flints Found in the Cliffs and on the Shore at Mundesley, Norfolk

1920 ◽  
Vol 3 (2) ◽  
pp. 219-243
Author(s):  
J. Reid Moir
Keyword(s):  
Present Author ◽  
The South ◽  
North West ◽  
The North ◽  
Close Proximity ◽  
Made In

When visiting Mundesley, in Norfolk, in September, 1916, the present author found upon the shore, in close proximity to an exposure of clay which he now considers to be referable to the Cromer Forest Bed Series, a very finely-made and large flint flake, of human manufacture. This discovery induced him to again visit Mundesley, and during this year (1919) close upon three weeks have been spent in an examination of the stretch of cliffs and shore lying between Trimingham, to the north-west of Mundesley, and Bacton, which lies to the south-east.The author's researches have been greatly helped by the co-operation of three friends, Professor A. S. Barnes, Mr. Walter B. Nichols, and the Hon. Robert Gathorne-Hardy, who accompanied him to Mundesley, and to whom he offers his warmest thanks. He would, however, wish to make it clear that these gentlemen are in no way responsible for the statements made in this paper. For these the author is solely responsible.

scholarly journals Seasonal Variation of Tannin and Nutrient in Aegiceras corniculatum Leaves in Zhangjiang Mangrove Ecosystem

2015 ◽  
Vol 9 (1) ◽  
pp. 143-148
Author(s):  
Minshen Huang ◽  
Lihua Zhang ◽  
Shudong Wei ◽  
Qi Zeng ◽  
Haichao Zhou ◽  
...  
Keyword(s):  
Condensed Tannins ◽  
Insect Pests ◽  
Mangrove Ecosystem ◽  
Plant Diseases ◽  
The Sun ◽  
Aegiceras Corniculatum ◽  
Significant Difference ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT) and nitrogen contents in sun and shade leaves of Aegiceras corniculatum were studied in the Zhangjiang Estuary, Fujian Province, China. The contents of TP, ECT and TCT in the sun leaves were significantly higher than those in the shade leaves through the season. The N content in sun leaves was higher than that in shade leaves in the autumn, while it was lower in the summer, and there was no significant difference in the winter and spring. With the respect to the P through the year, P content in the sun leaves was different between seasons, with the highest in winter and the lowest in summer. In addition, the TP:N and ECT:N ratios in sun leaves were significantly higher than those in shade leaves except in autumn. High tannin levels and TP:N and ECT:N ratios in the sun leaves not only can reduce oxidative stress, but also improve the ability of resisting plant diseases and insect pests.

scholarly journals Morphological and anatomical aspects of the leaves of Rhizophora mangle L. (Rhizophoraceae) under different lighting conditions / Aspectos morfológicos e anatômicos das folhas de Rhizophora mangle L. (Rhizophoraceae) sob diferentes condições de luz

2016 ◽  
Vol 12 (2) ◽  
pp. 74
Author(s):  
Camilla Reis Augusto da Silva ◽  
Marcelo Dos Santos Silva ◽  
Léa Maria Dos Santos Lopes Ferreira ◽  
Kelly Regina Batista Leite ◽  
Lazaro Benedito da Silva
Keyword(s):  
Stomatal Density ◽  
Rhizophora Mangle ◽  
Palisade Parenchyma ◽  
Abaxial Epidermis ◽  
Lighting Conditions ◽  
Ocular Micrometer ◽  
Significant Difference ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

The basis of differentiation between sun and shade leaves is related to different light intensities. In order to understand the adaptability of the leaves of Rhizophora mangle L., associated with different lighting conditions, leaves were collected from the upper peripheral six individuals (sun leaves) and the lower region of the same internal (shade leaves). The variables analyzed leaf thickness, palisade parenchyma, adaxial and abaxial epidermis, adaxial and abaxial cuticle, stomatal density and index. Measurements were made ??on microscope equipped with ocular micrometer. Sun leaves were lower and with more xeromorphic characteristics, such as increased thickness of the cuticle and the adaxial and abaxial epidermis. The palisade parenchyma and limbus showed up thicker than shade leaves, with no significant difference between the cuticle of the abaxial surface. It was also observed a higher frequency of stomata per mm², an average of 70/mm², while shade leaves showed 47/mm², with no differences between length and width. Differences between the sun leaves and shade leaves indicate adaptive capacity of this species to remain active at different light conditions.

Life before and after implementation of an acoustic noise reduction enclosure

2005 ◽  
Vol 109 (1092) ◽  
pp. 65-74
Author(s):  
B. Timmins
Keyword(s):  
Wind Tunnel ◽  
Noise Reduction ◽  
Acoustic Noise ◽  
Financial Health ◽  
Two Phase ◽  
North West ◽  
The North ◽  
Close Proximity ◽  
Before And After ◽  
Increase Productivity

Abstract This paper looks back on the designs and ambitions of ARA in resolving a long term acoustic noise problem which threatened ARA with closure. This paper today briefly looks back to the original issues but deals more fully with the later phases of a two phase project implementation and construction. ARA is now a truly ‘silent site’, where closure was once threatened, ARA has achieved the implementation of a bespoke noise reduction enclosure where 24-hour running has proved to be a reality. This paper looks at the design and construction phases, the ‘before and after’ noise footprints and at some of the financial benefits ARA has achieved. The ARA transonic wind tunnel is sited on an industrial estate on the north west perimeter of Bedford. When it was first built it was on an original farm site with no appreciable residential houses in close proximity. Since the early 1950s there has been considerable residential development around the ARA site resulting in the local householders complaining about the wind tunnel acoustic noise. In early 1999 ARA was obliged to consider several options for noise reduction measures to reduce the noise to within UK government statutory requirements. This paper deals briefly with the original noise nuisance characteristics and footprint, the noise reduction design and method that ARA selected and shows the construction phases, the further noise treatment ARA had to do on other major ancillary equipment to make ARA a truly quiet industrial site. The paper shows how ARA has utilised the resulting benefits of these investments to increase productivity and reduce costs, and the influence it has had on ARA’s financial health.

scholarly journals Four Departmental Asylums in the North-West of France

1874 ◽  
Vol 19 (88) ◽  
pp. 541-552
Author(s):  
J. Wilkie Burman
Keyword(s):  
Small Town ◽  
Great Majority ◽  
Waste Paper ◽  
Maintenance Rate ◽  
North West ◽  
The North ◽  
Walking Tour ◽  
Large Numbers ◽  
Close Proximity ◽  
Lunatic Asylums

In the course of a walking tour, during last summer, I visited, en route, four of the Departmental Lunatic Asylums in the North-West of France, principally with a view to see how they would stand comparison with our own Provincial or County Asylums. Such a comparison, however, could scarcely, I find, be made on a fair basis; for though, undoubtedly, the great majority of the patients in the French Departmental Asylums are paupers, and maintained at the expense of the several Departments, yet, in all, there are associated with these paupers large numbers of pensionnaires, who are maintained by theirfriends and divided into four or five classes, and treated according to their rate of payment. It is obvious, moreover, that the better general and special arrangements, due to and supported by the higher rates of payment of the pensionnaires, would prevent such associated asylums as these from being fairly compared, as to their tout ensemble, with our own County Asylums—in which, as a rule, the patients are all paupers, and chargeable to the different unions, and in which the arrangements are for paupers only, and so constituted as to keep the maintenance rate as low as is compatible with efficiency. Seeing, then, that it was impossible to institute any fair general comparison between the French Departmental Asylums, which I lately visited, and our own County Asylums, I determined, whilst not failing to pay all due regard to the arrangements for, and treatment of, the pensionnaires, to pay more particular attention to the condition and treatment of the pauper patients in the Asylums visited, and to take my notes accordingly. These rough notes, instead of consigning them to the waste paper basket, as has been the fate of former notes of visits made by me to Continental Asylums, I have, this time, determined to offer to my professional brethren, in the hope that they may afford, perhaps, some few crumbs of information and of interest. It will be necessary for me, however, before going further, to state—that, as the principal object of my tour was walking and not mad-house hunting, I did not follow out any predetermined plan as to which particular asylums I should visit. Indeed, it was not until I had well started on my tour that I conceived the laudable idea of endeavouring to combine a little instruction with my amusement, and the result was that I merely visited those asylums which were in close proximity to the route which I had arranged for myself previous to starting. The asylums to which I paid these hap-hazard visits, then, were the following:—1st, “L'Asile de Lehon,” Dinan; 2nd, “L'Asile St. Athanase,” Quimper; 3rd, “L'Asile St. Méen,” Rennes; and 4, “L'Asile de Pontorson,” situated in the small town of that name; and I shall record my notes of them, seriatim, in the order in which they were visited.

scholarly journals Four Departmental Asylums in the North-West of France

1874 ◽  
Vol 19 (88) ◽  
pp. 541-552
Author(s):  
J. Wilkie Burman
Keyword(s):  
Small Town ◽  
Great Majority ◽  
Waste Paper ◽  
Maintenance Rate ◽  
North West ◽  
The North ◽  
Walking Tour ◽  
Large Numbers ◽  
Close Proximity ◽  
Lunatic Asylums

In the course of a walking tour, during last summer, I visited, en route, four of the Departmental Lunatic Asylums in the North-West of France, principally with a view to see how they would stand comparison with our own Provincial or County Asylums. Such a comparison, however, could scarcely, I find, be made on a fair basis; for though, undoubtedly, the great majority of the patients in the French Departmental Asylums are paupers, and maintained at the expense of the several Departments, yet, in all, there are associated with these paupers large numbers of pensionnaires, who are maintained by theirfriends and divided into four or five classes, and treated according to their rate of payment. It is obvious, moreover, that the better general and special arrangements, due to and supported by the higher rates of payment of the pensionnaires, would prevent such associated asylums as these from being fairly compared, as to their tout ensemble, with our own County Asylums—in which, as a rule, the patients are all paupers, and chargeable to the different unions, and in which the arrangements are for paupers only, and so constituted as to keep the maintenance rate as low as is compatible with efficiency. Seeing, then, that it was impossible to institute any fair general comparison between the French Departmental Asylums, which I lately visited, and our own County Asylums, I determined, whilst not failing to pay all due regard to the arrangements for, and treatment of, the pensionnaires, to pay more particular attention to the condition and treatment of the pauper patients in the Asylums visited, and to take my notes accordingly. These rough notes, instead of consigning them to the waste paper basket, as has been the fate of former notes of visits made by me to Continental Asylums, I have, this time, determined to offer to my professional brethren, in the hope that they may afford, perhaps, some few crumbs of information and of interest. It will be necessary for me, however, before going further, to state—that, as the principal object of my tour was walking and not mad-house hunting, I did not follow out any predetermined plan as to which particular asylums I should visit. Indeed, it was not until I had well started on my tour that I conceived the laudable idea of endeavouring to combine a little instruction with my amusement, and the result was that I merely visited those asylums which were in close proximity to the route which I had arranged for myself previous to starting. The asylums to which I paid these hap-hazard visits, then, were the following:—1st, “L'Asile de Lehon,” Dinan; 2nd, “L'Asile St. Athanase,” Quimper; 3rd, “L'Asile St. Méen,” Rennes; and 4, “L'Asile de Pontorson,” situated in the small town of that name; and I shall record my notes of them, seriatim, in the order in which they were visited.

scholarly journals Carbon gain optimization in five broadleaf deciduous trees in response to light variation within the crown: correlations among morphological, anatomical and physiological leaf traits

2015 ◽  
Vol 74 (1) ◽  
pp. 71-94 ◽  
Author(s):  
Rosangela Catoni ◽  
Loretta Gratani ◽  
Francesco Sartori ◽  
Laura Varone ◽  
Mirko U. Granata
Keyword(s):  
Phenotypic Plasticity ◽  
Deciduous Forest ◽  
Light Variation ◽  
Stress Factors ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Deciduous Species ◽  
Shade Leaves ◽  
Sun Leaves

AbstractLeaf trait variations in five deciduous species (Quercus robur, Corylus avellana, Populus alba, Acer campestre, Robinia pseudoacacia) growing in an old broadleaf deciduous forest in response to light variation within the tree crown was analyzed. Net photosynthetic rate (PN), leaf respiration rate (R) and the photosynthetic nitrogen use efficiency were, on average, more than 100% higher in sun than in shade leaves. A. campestre and C. avellana sun leaves had the highest specific leaf area (SLA, 156.0 ± 17.9 cm2 g-1) and the lowest total leaf thickness (L, 101.9 ± 8.8 μm) underlining their shade-tolerance. Among the shade-intolerant species (Q. robur, P. alba and R. pseudoacacia), Q. robur had the lowest SLA and the highest L in sun leaves (130.6 ± 10.0 cm2 g-1 and 160.8 ± 9.6 μm, respectively) since shade-intolerant species typically have thicker leaves. The higher PN decrease in respect to R decrease from sun to shade leaves attested the higher sensitivity of PN than R to light variations within the crown. This determined a 69% lower R/PN in sun than in shade leaves. This result is further attested by the significant correlation between PN and the relative photosynthetic photon flux density. The shade-tolerant species have a 76% higher R/PN ratio than the shade-intolerant ones. The measured leaf phenotypic plasticity (PI = 0.35) was in the range of broadleaf deciduous species. Plasticity is a key trait useful to quantify plant response to environmental stimuli. It is defined as the ability of a genotype to produce different phenotypes depending on the environment. Among the considered species, Q. robur showed the highest PI (0.39) and P. alba the lowest (0.29). Knowledge on phenotypic plasticity is important in making hypotheses about the dynamics of the studied forest in consideration of environmental stress factors, including invasive species competition and global climate change.

A LEAF-TISSUE GALL ON MOUNTAIN COTTONWOOD

1894 ◽  
Vol 26 (8) ◽  
pp. 223-223
Author(s):  
C. H. Tyler Townsend
Keyword(s):  
New Mexico ◽  
Leaf Tissue ◽  
The North

A fleshy leaf-tissue gall was found on terminal twigs of Populus Monilifera(?) June 18, 1892, a few miles to the north of Ojo Caliente, in Southern Socorro county, New Mexico. This gall is somewhat similar in method of formation to one that has been found on Rhus microphylla, which possesses a cock's-comb-like appearnce.

Sign in / Sign up

Export Citation Format

Share Document