Site and Seasonal Effects on Susceptibility of Eucalyptus marginata to Phytophthora cinnamomi

Susceptibility of Eucalyptus marginata stems and roots to invasion by Phytophthora cinnamomi was compared at four sites in the northern jarrah forest and reasons for differences in tree susceptibility were sought. The sites were located in both the low (750 mm year -I ) and high (1 100 mm year -1) rainfall zones and differed in understorey composition and soil nutrient status. Stems were inoculated at monthly intervals between October 1983 and April 1984. Measurement of stem lesions induced by inoculation showed that rate of fungal growth in trees at all sites generally increased during the October-December (1983) period. During February and March (1984) there was a large difference in the susceptibility of stems and roots in low-rainfall zone sites compared with those in high-rainfall zone sites. Roots inoculated during February at three of the four sites showed the same relative susceptibilities as stems inoculated one week later. Mean relative water contents (RWC) of the phloem (inner bark) were used to compare the water status of the saplings at the four sites and the observed inhibition of the fungus in the sapling stems and roots at the driest sites, coincided with the months when phloem RWC values were at their lowest. Phloem was also sampled from pole-sized trees at the four sites and seasonal changes in RWC values, soluble carbohydrate concentrations and phenols were monitored for 12 months. Soluble carbohydrate concentrations in the phloem of some of the saplings inoculated at each site were also determined. Concentrations of carbohydrates and phenols did change seasonally and differed between sites but no evidence was found to suggest that they had a direct effect on fungal growth.

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Relations Between Mn Concentration and Yield, Nutrient, Water Status, and Gas Exchange Parameters of Tomato

Acta Biologica Cracoviensia s Botanica ◽

10.2478/abcsb-2014-0030 ◽

2015 ◽

Vol 56 (2) ◽

pp. 98-106

Author(s):

Tomasz Kleiber ◽

Klaudia Borowiak ◽

Anna Budka ◽

Dariusz Kayzer

Keyword(s):

Gas Exchange ◽

Photosynthetic Activity ◽

Water Status ◽

Nutrient Status ◽

Nutrient Content ◽

Gas Exchange Parameters ◽

Tomato Yield ◽

Relative Water ◽

Mn Concentration ◽

Exchange Parameters

Abstract Nutrition is one of the most important factors influencing quantitative and qualitative plant yield. This study examined the effect of manganese (Mn) in nutrient solution on photosynthetic activity parameters, and the relations between photosynthetic activity parameters, yield and plant nutrient status in tomato (Solanum lycoper-sicum L.). Mn supplementation significantly modified the nutrient content of leaves. Macronutrient content var-ied less than micronutrient content. The optimal Mn concentration differed between the studied cultivars. Both Mn deficit and Mn excess caused a decrease of tomato yield. Gas exchange parameters, relative water content (RWC) and specific leaf area (SLA) were measured in fully expanded tomato leaves. Certain levels of Mn were found to be needed for proper plant function and future yield, and toxic effects of excess Mn were noted. Changes in PN (net photosynthetic rate) were found to be the first signal of plant response to higher Mn supply, while yield was as for optimal Mn concentrations. Under Mn treatment, uptake of some nutrients increased. A higher level of absorbed Mg led to a higher photosynthesis rate and increased stomatal opening. PN and gs (stomatal con-ductance) also increased, while Ci (intercellular CO2 concentration) decreased, indicating proper CO2 consumption during the assimilation process.

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Formation of Mycorrhizae by Jarrah (Eucalyptus marginata Donn ex Smith) in Litter and Soil

Australian Journal of Botany ◽

10.1071/bt9840511 ◽

1984 ◽

Vol 32 (5) ◽

pp. 511 ◽

Cited By ~ 52

Author(s):

P Reddell ◽

N Malajczuk

Keyword(s):

Arbuscular Mycorrhizae ◽

Prescribed Burning ◽

Habitat Preferences ◽

Fungal Growth ◽

Nutrient Status ◽

Nitrogen And Phosphorus ◽

Eucalyptus Marginata ◽

Factors Affecting ◽

Main Site ◽

Vesicular Arbuscular

In soils under forest conditions and on seedlings grown under glasshouse conditions jarrah mycorrhizae exhibited strong habitat preferences. Litter on the forest floor was the main site for the formation of the white and brown ectomycorrhizae, and removal of the litter layer by prescribed burning reduced by 90% the numbers of these two ectomycorrhizae. Black ectornycorrhizae were dominant in the mineral horizons of soil and were unaffected by the type of surface litter. In glasshouse experiments litter from different plant species significantly influenced formation of ectomycorrhizae by jarrah seedlings. Litter from Acacia pulchella R. Br. was favourable for formation of ectomycorrhizae but ectornycorrhizae were absent from Banksia grandis Willd. litter. Black ectomycorrhizae, Hysterangium- initiated ectomycorrhizae and vesicular arbuscular mycorrhizae formed on jarrah seedlings in the soils used in glasshouse studies. Addition of nitrogen and phosphorus to these soils influenced the relative abundance of mycorrhizae. It is postulated that inoculum levels, nutrient status of litter and soil and the presence of compounds inhibitory to fungal growth are critical in determining the abundance of mycorrhizae. Factors affecting formation of mycorrhizae by jarrah and the ecological implications of these results are discussed.

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Variations in α–, β–Amylase and α–Glycosidase Activities in Two genotypes of Wheat Under NACL Salinity Stress

Plant Breeding and Seed Science ◽

10.2478/v10129-011-0060-8 ◽

2014 ◽

Vol 66 (1) ◽

pp. 89-97 ◽

Cited By ~ 2

Author(s):

Chaffei Haouari Chiraz ◽

Hajjaji Nasraoui Afef ◽

Bouthour Donia ◽

Gouia Houda

Keyword(s):

Salt Stress ◽

Water Status ◽

Soluble Sugars ◽

Germination Percentage ◽

Soluble Carbohydrate ◽

Inhibitory Effects ◽

Total Soluble Sugars ◽

Germination Process ◽

Nacl Concentration ◽

Relative Water

Abstract Two wheat differing in salt sensitivity, was examined for osmolyte contents and activities of α-amylase, β-amylase and α-glucosidase enzymes involved in seeds germination, in absence as well as in presence of 100, 150, 200 and 300 mM NaCl. The inhibitory effects of NaCl differed, depending on the species tested. In wild wheat specie (Triticum monococcum), with reduced germination percentage and lower relative water content, the increase in NaCl concentration resulted in the decrease in endogenous level of proline, total soluble sugars and activities of the main enzymes involved in the germination process. In contrast, cultivated wheat specie (Triticum aestivum) seed in response to salt stress accumulated higher proline and total soluble carbohydrate concentrations which improved their water status and the enzyme activities involved in the germination process. Differential response of the different species of wheat to salt stress is governed by the accumulation of osmolytes in seeds.

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Morphological Differences in Lignotubers of Eucalyptus intermedia R.T. Bak. And E. signata F. Muell. Associated With Different Stages of Podzol Development on Coastal Dunes, Cooloola, Queensland

Australian Journal of Botany ◽

10.1071/bt9870301 ◽

1987 ◽

Vol 35 (3) ◽

pp. 301 ◽

Cited By ~ 10

Author(s):

J Walker ◽

CH Thompson ◽

CJ Lacey

Keyword(s):

Water Status ◽

Salt Spray ◽

Soil Nutrient ◽

Coastal Dunes ◽

Nutrient Status ◽

Fire Regimes ◽

Nutrient Supply ◽

Dune System ◽

Factors Affecting ◽

Coastal Margin

The sandmass at Cooloola comprises a series of overlapping aeolian dune systems that extend in age from the present back more than 100 000 years. Podzols are the dominant soils, forming a sequence from rudimentary through to giant forms, according to age. The lignotuber morphology of Eucalyptus signata and E. intermedia was examined within each dune system across the chronosequence, at sites in which most factors affecting plant growth (available soil water status, drainage, light, temperature, fire regimes, exposure to wind and/or salt spray) other than a declining soil nutrient supply were similar. Three lignotuber morphologies were identified: (1) a single-stemmed (SS) form; (2) a multi-stemmed (MS) form with stems originating from a lignotuber only slightly larger than a main stem; and (3) a multi-stemmed plate-like form (MSP) with individual stems separated and growing from a plate-like lignotuber. Multi-stemmed forms of the two eucalypts occur along the coastal margin and on the most nutrient- poor dunes; at all other sites single-stemmed forms are dominant. The most nutrient-poor site had only MS and MSP forms, whilst in sheltered areas the coastal margin had SS individuals. We conclude that in the Cooloola sandmass the development of multi-stemmed forms in both E. signata and E. intermedia may be induced by a variety of factors, including very low nutrient status, but the multi-stemmed plate-like form of E. intermedia is most likely a response to an exceptionally low nutrient supply.

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The Method of Plant Water Status Measurement in Sweet Potato (Ipomoea Batatas (L) Lam.)

Beccariana Botanical Research Bulletin ◽

10.30862/bbrp.v7i1.274 ◽

2010 ◽

Vol 7 (1) ◽

Author(s):

Saraswati Prabawardani

Keyword(s):

Water Content ◽

Sweet Potato ◽

Relative Water Content ◽

Water Status ◽

Plant Water Status ◽

Equilibration Time ◽

Plant Water ◽

Font Size ◽

Potato Leaf ◽

Relative Water

The measurement of plant water status such as leaf water potential (LWP) and leaf relative water content (RWC) is important part of understanding plant physiology and biomass production. Preliminary study was made to determine the optimum amount of leaf abrasion and equilibration time of sweet potato leaf inside the thermocouple psychrometer chambers. Based on the trial, the standard equilibration time curve of a Peltier thermocouple for sweet potato leaf was between 2 and 3 hours. To increase the water vapour conductance across the leaf epidermis the waxy leaf cuticle should be removed or broken by abrasion. The result showed that 4 times leaf rubbings was accepted as the most effective way to increase leaf vapour conductance of sweet potato in the psychrometer chambers. In calculating the leaf relative water content, unstressed water of sweet potato leaves require 4 hours imbibition, whereas water stressed of sweet potato leaves require 5 to 6 hours to reach the saturation time. Either leaf water potential or relative water content can be used as a parameter for plant water status in sweet potato.

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Integration of soil and foliar nutrition in influencing the yield related characters, yield and economics of nendran banana (musa aab group) and the soil nutrient status of cropped field

Journal of Crop and Weed ◽

10.22271/09746315.2020.v16.i1.1282 ◽

2020 ◽

Vol 16 (1) ◽

pp. 127-132

Author(s):

E.K. BASHMA ◽

B. SUDHA

Keyword(s):

Soil Nutrient ◽

Nutrient Status ◽

Soil Nutrient Status ◽

Foliar Nutrition

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Infection by Phytophthora cinnamomi Rands of Roots of Eucalyptus calophylla R.Br. and Eucalyptus marginata Donn. ex Sm

Australian Journal of Botany ◽

10.1071/bt9770483 ◽

1977 ◽

Vol 25 (5) ◽

pp. 483 ◽

Cited By ~ 16

Author(s):

N Malajczuk ◽

AJ Mccomb ◽

CA Parker

Keyword(s):

Phytophthora Cinnamomi ◽

Light And Electron Microscopy ◽

Inhibitory Effect ◽

Lateritic Soil ◽

Root Damage ◽

Mature Trees ◽

Cortical Cells ◽

Eucalyptus Marginata ◽

Seedling Roots ◽

Loam Soil

On lateritic podzolic soils in Western Australia Eucalyptus calophylla is resistant to Phytophthora cinnamomi whereas Eucalyptus marginata is susceptible and eventually killed by the pathogen. On loam soils both eucalypts are resistant. Possible mechanisms for resistance of E. calophylla in lateritic soil and the inhibitory action of loam soils were investigated. Aseptically raised eucalypt seedlings succumbed to infection in liquid culture tubes. The mechanism of infection was compared by light and electron microscopy which showed similar fungal invasion and penetration into roots of both eucalypt species. Vegetative hyphae initially penetrated intercellularly and proliferated rapidly within cortical and stelar tissue. Intracellular invasion of these tissues occurred 48hr after initial infection through dissolution of the host cell wall. Chlamydospores were formed within a number of cortical cells. Unsuberized roots of mature trees produced aseptically showed reactions to invasion similar to those of the eucalypt seedling roots. Suberized roots were not invaded. The addition of small quantities of lateritic soil to sterile sand so as to introduce soil micro-organisms without altering the chemical and physical status of the sand, and subsequent inoculation of the sand with P.cinnamomi, resulted in a reduction of root damage on both eucalypts when compared with seedlings raised in sterile sand. Roots of E.calophylla were less severely damaged than those of E.marginata. The addition of small quantities of loam soil significantly reduced root damage in seedlings of both species. These results parallel both pot experiments and field observations, and suggest that microorganisms of the rhizosphere may be an important factor in the resistance of E.calophylla to infection, and in the inhibitory effect of loam soil on P.cinnamomi.

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