scholarly journals Specialized 16SrX phytoplasmas induce diverse morphological and physiological changes in their respective fruit crops

2021 ◽  
Vol 17 (3) ◽  
pp. e1009459
Author(s):  
Jannicke Gallinger ◽  
Kerstin Zikeli ◽  
Matthias R. Zimmermann ◽  
Louisa M. Görg ◽  
Axel Mithöfer ◽  
...  
Keyword(s):  
Mass Flow ◽  
Prunus Persica ◽  
Vascular System ◽  
Morphological Changes ◽  
Physiological Changes ◽  
Apple Trees ◽  
Callose Deposition ◽  
Phloem Sap ◽  
Phytoplasma Infection ◽  
Pear Trees

The host-pathogen combinations—Malus domestica (apple)/`Candidatus Phytoplasma mali´, Prunus persica (peach)/`Ca. P. prunorum´ and Pyrus communis (pear)/`Ca. P. pyri´ show different courses of diseases although the phytoplasma strains belong to the same 16SrX group. While infected apple trees can survive for decades, peach and pear trees die within weeks to few years. To this date, neither morphological nor physiological differences caused by phytoplasmas have been studied in these host plants. In this study, phytoplasma-induced morphological changes of the vascular system as well as physiological changes of the phloem sap and leaf phytohormones were analysed and compared with non-infected plants. Unlike peach and pear, infected apple trees showed substantial reductions in leaf and vascular area, affecting phloem mass flow. In contrast, in infected pear mass flow and physicochemical characteristics of phloem sap increased. Additionally, an increased callose deposition was detected in pear and peach leaves but not in apple trees in response to phytoplasma infection. The phytohormone levels in pear were not affected by an infection, while in apple and peach trees concentrations of defence- and stress-related phytohormones were increased. Compared with peach and pear trees, data from apple suggest that the long-lasting morphological adaptations in the vascular system, which likely cause reduced sap flow, triggers the ability of apple trees to survive phytoplasma infection. Some phytohormone-mediated defences might support the tolerance.

The physiological and biochemical effects on Napier grass plants following Napier grass stunt phytoplasma infection

2020 ◽  
Author(s):  
GEORGE OCHIENG ASUDI ◽  
Keziah Moraa Omenge ◽  
Maria K Paulmann ◽  
Michael Reichelt ◽  
Veit Grabe ◽  
...  
Keyword(s):  
Vascular System ◽  
Morphological Changes ◽  
Napier Grass ◽  
Primary Metabolism ◽  
Oxygen Species ◽  
Biochemical Effects ◽  
Phytoplasma Infection ◽  
Total Dna ◽  
Physiological And Biochemical ◽  
Chloroplastic Pigments

Napier grass stunt (NGS) phytoplasma, a phloem limited bacterium, infects Napier grass leading to severe yield losses in East Africa. The infected plants are strongly inhibited in growth and biomass production. In this study, phytoplasma-induced morphological changes of the vascular system and physiological changes were analysed and compared with uninfected plants. The study showed that the phytoplasmas are more abundant in source leaves and range from 103 bacteria/µg total DNA in infected roots to 106 in mature Napier grass leaves. Using microscopical, biochemical and physiological tools, we demonstrated that the ultrastructure of the phloem and sieve elements is severely altered in the infected plants, which results in the reduction of the both mass flow and the translocation of photoassimilates in the infected leaves. The reduced transport rate inhibits the photochemistry of photosystems II in the infected plants, which is accompanied by loss of chloroplastic pigments in response to the phytoplasma infection stress eventually resulting in yellowing of diseased plants. The phytoplasma infection stress also causes imbalances in the levels of defense-related antioxidants, glutathione and ascorbic acid, reactive oxygen species (ROS) and in particular hydrogen peroxide. This study shows that the infection of NGS phytoplasma in the phloem of Napier grass has an impact on the primary metabolism and activates a ROS dependent defense response.

scholarly journals Phytoplasma occurrence in apple trees in the Czech Republic

2011 ◽  
Vol 39 (No. 1) ◽  
pp. 7-12 ◽  
Author(s):  
R. Fialová ◽  
M. Navrátil ◽  
P. Válová
Keyword(s):  
Fragment Length Polymorphism ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
Apple Proliferation ◽  
Chain Reaction ◽  
Apple Trees ◽  
The Czech Republic ◽  
High Incidence ◽  
Phytoplasma Infection ◽  
Polymerase Chain

The presence of phytoplasmas in apple trees with proliferation symptoms, rubbery wood symptoms and no symp­toms was determined by using polymerase chain reaction assays with primers amplifying phytoplasma 16S rRNA gene. Phytoplasmas were detected in all trees with proliferation symptoms. Positive tests for phytoplasma in the group of trees with rubbery wood symptoms and of those without symptoms revealed a relatively high incidence of latent phytoplasma infection. Using restriction fragment length polymorphism analysis, phytoplasma of the same identity – apple proliferation phytoplasma (subgroup 16SrX-A) – was recorded in all positively tested trees.  

Herbicide Effects on Weed Control and Shoot Growth of Young Apple (Malus sylvestris) and Peach (Prunus persica) Trees

1994 ◽  
Vol 8 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Chester L. Foy ◽  
Susan B. Harrison ◽  
Harold L. Witt
Keyword(s):  
Shoot Growth ◽  
Field Experiments ◽  
Prunus Persica ◽  
Weed Species ◽  
Apple Trees ◽  
Herbicide Treatments ◽  
One Year ◽  
Broadleaf Species ◽  
Old Trees ◽  
Peach Trees

Field experiments were conducted at two locations in Virginia to evaluate the following herbicides: alachlor, diphenamid, diuron, metolachlor, napropamide, norflurazon, oryzalin, oxyfluorfen, paraquat, pendimethalin, and simazine. One experiment involved newly-transplanted apple trees; the others, three in apple and one in peach trees, involved one-year-old trees. Treatments were applied in the spring (mid-April to early-May). Control of annual weed species was excellent with several treatments. A broader spectrum of weeds was controlled in several instances when the preemergence herbicides were used in combinations. Perennial species, particularly broadleaf species and johnsongrass, were released when annual species were suppressed by the herbicides. A rye cover crop in nontreated plots suppressed the growth of weeds. New shoot growth of newly-transplanted apple trees was increased with 3 of 20 herbicide treatments and scion circumference was increased with 11 of 20 herbicide treatments compared to the nontreated control. Growth of one-year-old apple trees was not affected. Scion circumference of one-year-old peach trees was increased with 25 of 33 herbicide treatments.

scholarly journals Lichens of fruit trees in the selected locations in Podlaskie Voivodeship [North-Eastern Poland]

2017 ◽  
Vol 28 (4) ◽  
pp. 5-9 ◽  
Author(s):  
Anna Matwiejuk
Keyword(s):  
Fruit Trees ◽  
Lichen Species ◽  
Apple Trees ◽  
Partial Protection ◽  
Lichen Biota ◽  
North Eastern ◽  
Pear Trees ◽  
Fruit Orchards ◽  
Ramalina Farinacea

Abstract The aim of this paper is to present the diversity of the lichen species on fruit trees (Malus sp., Pyrus sp., Prunus sp. and Cerasus sp.) growing in orchards in selected villages and towns in the Podlaskie Voivodeship. Fifty-six species of lichens were found. These were dominated by common lichens found on the bark of trees growing in built-up areas with prevailing heliophilous and nitrophilous species of the genera Physcia and Phaeophyscia. A richer lichen biota is characteristic of apple trees (52 species) and pear trees (36). Lichens of the apple trees constitute 78% of the biota of this phorophyte growing in the fruit orchards in Poland. Of the recorded species, only two (Ramalina farinacea, Usnea hirta) are covered by partial protection in Poland.

Transport of Tritiated Water and 14c-Labelled Assimilate Into Grains of Wheat. III. Diffusion of Tho Through the Stalk

1985 ◽  
Vol 12 (6) ◽  
pp. 595 ◽  
Author(s):  
CF Jenner
Keyword(s):  
Mass Flow ◽  
Short Distance ◽  
Vascular System ◽  
Tritiated Water ◽  
The Self ◽  
Wheat Grain ◽  
Physical Processes ◽  
Self Diffusion ◽  
Separate System ◽  
Flow Through

Measuring the rate at which tritiated water is transported by diffusion through the stalk of the wheat grain is the main purpose of this paper. Diffusion of THO through the stalk is much slower than expected on the basis of the self-diffusion of THO in water, demonstrating that there are substantial resistances to diffusion of water in the stalk. Entry of THO into the grain by physical processes alone (diffusion), as measured in assemblies in which the grain (stripped of its bracts) is sealed into an impermeable capsule, is fast enough to account for the observed rate of transport of THO into normally functioning grains. Metabolically linked transport of water through the stalk is not detectable. Either the volume of water involved in mass flow through the stalk is too low to be detectable - which would require the concentration of sucrose to be about 2 M, or the entry of assimilate is not accompanied by water. Short-distance transfer of solute (only) from the plant's vascular system to a separate system servicing the grain seems the simplest explanation on the basis of the available evidence.

Some morphological, anatomical, and physiological changes in the pear fruit (Pyrus communis var. Williams Bon Chrétien) during development and following harvest

1961 ◽  
Vol 9 (2) ◽  
pp. 99 ◽  
Author(s):  
JM Bain
Keyword(s):  
Cell Division ◽  
Morphological Changes ◽  
Complex Structure ◽  
Titratable Acidity ◽  
Dry Weight ◽  
Cell Number ◽  
Pyrus Communis ◽  
Physiological Changes ◽  
Pear Fruit ◽  
Protein Nitrogen

Morphological, anatomical, and physiological changes occurring in the developing fruit of Pyrus communis var. Williams Bon Chretien were studied at frequent intervals, from blossom until after commercial maturity, in three successive seasons. Morphological changes were shown by increase in measurements of volume, long and short axis, and the width of the cortex (flesh), the morphology of the fruit being interpreted by the receptacular theory, Anatomical changes were given by the duration and distribution of cell division, differentiation of tissues, cell size, and cell number. Physiological changes were expressed as changes in fresh weight, dry weight, and moisture content for the whole fruit, and separately for the flesh, peel, and core in the second and third seasons. Total and reducing sugars, starch, titratable acidity, and total and protein nitrogen were estimated per gram of dried flesh at each sampling. Respiration rates for whole fruit were measured by the Pettenkofer method. Physiological changes could not be expressed on a per cell basis because of the complex structure of pear tissue. Data presented on the basis of the number of days from blossom showed two distinct stages in fruit growth. Stage I, the first 42-56 days of development, corresponded to the main cell division period and was characterized by more rapid morphological but slower physiological changes (except for increase in protein nitrogen) than Stage 11, the remainder of the time on the tree. Comparable trends were found in the three seasons, but drought reduced growth rate in the first season. Some ripening changes were followed on removal from the tree and after periods of cold storage at 0°C.

Morphological changes accompanying physiological changes in atrial stretch receptors

1980 ◽  
Vol 75 (4) ◽  
pp. 510-514 ◽  
Author(s):  
A. M. Earle ◽  
I. H. Zucker ◽  
A. C. Earle ◽  
J. P. Gilmore
Keyword(s):  
Morphological Changes ◽  
Physiological Changes ◽  
Stretch Receptors

PHYSICAL - CHEMICAL AND PHYSIOLOGICAL CHANGES DURING THE RIPENING OF PARAGUAYO (PRUNUS PERSICA, L.)

1998 ◽  
pp. 399-404 ◽  
Author(s):  
M.T. Pretel ◽  
M.C. Martinez-Madrid ◽  
M. Serrano ◽  
G. Martinez-Reina ◽  
F. Romojaro
Keyword(s):  
Prunus Persica ◽  
Physiological Changes ◽  
Physical Chemical

scholarly journals 505 Sensitivity of Pear and Apple Plants to Urea Fertilizers

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 481E-481
Author(s):  
Shufu Dong ◽  
Lailiang Cheng ◽  
Guihong Bi ◽  
Leslie H. Fuchigami
Keyword(s):  
Soil Sample ◽  
The Other ◽  
Soil Test ◽  
Distilled Water ◽  
Apple Trees ◽  
Leaf Necrosis ◽  
Pear Trees ◽  
Terminal Buds

`Gala'/M26 apple and `Bartlett'/OH97 pear trees growing in containers were treated with either 0, 1, 5, 10, 20, or 30g of urea dissolved in 150 mL of distilled water on 7 Sept. 1999. Two weeks after application, a soil sample from each container was analyzed for NH4+ and NO3–. One day after treatment, the leaves of the apple trees treated with either 20 or 30 g urea wilted and curled and none of the other apple treatments were affected. However, 20 days later, new lateral and terminal buds broke to grow from these two treatments. In contrast, the pear trees showed signs of wilting and leaf necrosis in the 5, 10, 20, and 30 g urea treatments about 6 days after application. Twenty days after treatment, the leaves from the two highest treatments were completely necrotic and remained attached to the trees, while the leaves of 5- and 10-g treatments were partially necrotic and began defoliating. None of the pear trees produced any new lateral or terminal growth. Soil test showed that NH4+ contents of the soils were 54.9, 104.2, 356.9, 884.28, 1154.9, and 1225.2 mg/kg for `Bartlett'/OH97, and 30.2, 62.9, 359.0, 235.1, 529.9, and 499.0 mg/kg for `Gala'/M26 and NO3– contents of the soils were 40.5, 62.4, 211.0, 129.8, 54.5, and 39.5 mg/kg for `Bartlett'/OH97, and 37.6, 42.0, 178.7, 138.2, 186.2, and 142.1 mg/kg for `Gala'/M26 treated with 0, 1, 5, 10, 20, and 30 g urea, respectively.

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