1,721,158 research outputs found
Vegetable Crops: Improvement of Tolerance to Adverse Chemical Soil Conditions by GraftingImproving Crop Resistance to Abiotic Stress
No full textOwing to limited availability of arable land and the high market demand for
vegetables around the world, Solanaceae and Cucurbitaceae crops are frequently
cultivated under unfavorable soil conditions. These include salinity, alkalinity, heavy
metals, and excessive amount of trace elements. Plants exposed to adverse chemical
soil conditions exhibit various physiological and biochemical disorders leading to
stunted growth and severe yield loss. One way to avoid or reduce losses in production
caused by adverse soil chemical conditions in vegetables would be to graft them onto
rootstocks capable of reducing the effect of external stresses on the shoot. Grafting is
an integrative reciprocal process and, therefore, both scion and rootstock can
influence tolerance of grafted plants to adverse soil chemical conditions. Grafted
plants grown under adverse soil chemical conditions often exhibited greater growth
and yield, higher photosynthesis, better nutritional status, and lower accumulation of
Naþ and/or Cl, heavy metals, and excessive amount of trace elements in shoots than
ungrafted or self-grafted plants. This chapter gives an overview of the recent literature
on the response of grafted plants to adverse soil chemical conditions and the
mechanisms of tolerance to adverse soil chemical conditions in grafted plants related
to the morphological root characteristics and the physiological and biochemical
processes. The chapter will conclude by identifying several prospects for future
research aiming to improve the role of grafting in vegetable crops grown under
abiotic stress conditions
Mitigation of alkaline stress by arbuscular mycorrhiza in zucchini plants grown under mineral and organic fertilization
No full textA greenhouse experiment was carried out during the spring–summer 2009 to test the hypotheses
that: (1) arbuscular-mycorrhizal (AM) inoculation with a biofertilizer containing Glomus
intraradices gives an advantage to overcome alkalinity problems, (2) mineral fertilization is more
detrimental to AM development than organic fertilization on an equivalent nutrient basis. Arbuscular
mycorrhizal (AM) and non-AM of zucchini (Cucurbita pepo L.) plants were grown in sand
culture with two pH levels in the nutrient solution (6.0 or 8.1) and two fertilization regimes
(organic or mineral). The high-pH nutrient solution had the same basic composition as the lowpH
solution, plus an additional 10 mM NaHCO3 and 0.5 g L–1 CaCO3. Increasing the concentration
of NaHCO3 from 0 to 10 mM in the nutrient solution significantly decreased yield, plant
growth, SPAD index, net assimilation of CO2 (ACO2
), N, P, Ca, Mg, Fe, Mn, and Zn concentration
in leaf tissue. The +AM plants under alkaline conditions had higher total, marketable yield and
total biomass compared to –AM plants. The higher yield and biomass production in +AM plants
seems to be related to the capacity of maintaining higher SPAD index, net ACO2
, and to a better
nutritional status (high P, K, Fe, Mn, and Zn and low Na accumulation) in response to bicarbonate
stress with respect to –AM plants. The percentage root colonization was significantly higher
in organic-fertilized (35.7%) than in mineral-fertilized plants (11.7%). Even though the AM root
colonization was higher in organic-fertilized plants, the highest yield and biomass production
were observed in mineral-fertilized plants due to the better nutritional status (higher N, P, Ca,
and Mg), higher leaf area, SPAD index, and ACO2
Impact of grafting on product quality of fruit vegetables
No full textIn horticulturalindustry,thefocushastraditionallybeenonyield.However,inrecentyearsconsumers
interest inthequalityofvegetableproductshasincreasedworldwide.Vegetablequalityisabroadterm
and includesphysicalproperties(1),flavor(2),andhealth-relatedcompounds(3).Graftingvegetable
plants ontoresistantrootstocksisaneffectivetoolthatmayenablethesusceptiblesciontocontrolsoil-
borne diseases,environmentalstressesandincreaseyield.However,inthesecases,thecharacteristics
of thethreeareasmightbeaffectedbygraftingasaresultofthetranslocationofmetabolitesassociated
with fruitqualitytothescionthroughthexylemand/ormodificationofthephysiologicalprocessesof
the scion.Possiblequalitycharacteristicsshowingtheseeffectscouldbefruitappearance(size,shape,
color, andabsenceofdefectsanddecay),firmness,texture,flavor(sugar,acids,andaromavolatiles)and
health-related compounds(desiredcompoundssuchasminerals,vitamins,andcarotenoidsaswellas
undesired compoundssuchasheavymetals,pesticidesandnitrates).Therearemanyconflictingreports
on changesinfruitqualityduetograftingandwhethergraftingeffectsareadvantageousordeleterious.
The differencesinreportedresultsmaybeattributableinparttodifferentproductionmethodsandenvi-
ronments, typeofrootstock/scioncombinationsused,andharvestdate.Thisreportgivesanoverviewof
the recentliteratureontheeffectsofgraftingonfruitvegetable(SolanaceaeandCucurbitaceae)qual-
ity includingphysicalproperties,flavorandhealth-relatedcompoundsoftheproduct.Thereviewwill
conclude byidentifyingseveralprospectsforfutureresearchesaimingtoimprovetheproductqualityof
grafted vegetables
Nitrogen-use efficiency traits of mini-watermelon in response to grafting and nitrogen-fertilization doses
No full textTwo experiments were conducted to study the effect of grafting on nitrogen-use efficiency (NUE)
in mini-watermelon plants. In the first study, mini-watermelon plants (Citrullus lanatus [Thumb.]
Matsum. and Nakai cv. Minirossa) either ungrafted or grafted onto Macis, Vita (Lagenaria siceraria
[Mol.] Standl.), PS1313, and RP15 (Cucurbita maxima Duchesne × Cucurbita moschata
Duchesne) rootstocks grown in hydroponics were compared in terms of shoot dry biomass, leaf
area, root-to-shoot ratio, SPAD index, shoot N uptake, and nitrate reductase (NR) activity 40 d
after transplantation in response to nitrate concentration in the nutrient solution (0.5, 2.5, 5, 10,
15, or 20 mM of NO
3 ). In the second experiment, the suitability of a selected rootstock with high
NUE (Vita) to improve crop performance and NUE of grafted mini-watermelon plants was evaluated
under field conditions. In the hydroponic experiment mini-watermelon grafted onto Vita rootstock
needed the lowest nitrate concentration (1.31 mM of NO3) in the nutrient solution to reach
half maximum shoot dry weight. Total leaf area, SPAD index, and shoot N uptake increased in
response to an increase of N concentration in the nutrient solution. At 2.5 mM NO
3 , mini-watermelon
grafted on either Vita or RP15 had the highest NR activity whereas no significant difference
was observed at 10 mM NO
3 . The open-field study indicated that increasing N-fertilization
rates from 0 to 100 kg ha–1 improved total and marketable yields of mini-watermelon plants while
decreasing NUE. When averaged over N levels, the marketable yield, NUE, N-uptake efficiency,
and N-utilization efficiency were significantly higher by 39%, 38%, 21%, and 17%, respectively,
in Minirossa grafted onto Vita compared to ungrafted Minirossa plants. Therefore, grafting miniwatermelon
plants onto selected rootstocks can be used as a quick and effective method for
improving productivity and NUE
The effectiveness of grafting to improve alkalinity tolerance in watermelon
No full textThe aim of the present study was to determine whether grafting could improve alkalinity tolerance of
watermelon, and to study the changes induced by the rootstock in the shoot growth at agronomical, physiological,
and biochemical levels. Two greenhouse experiments were carried out to determine growth,
net photosynthetic rate, electrolyte leakage, root Fe(III)-chelate reductase (FCR) activity, mineral composition
and assimilate partitioning (experiment 1, 2007), and organic acid concentration in root exudates
(experiment 2, 2008), of watermelon plants [Citrullus lanatus (Thumb.) Matsum. and Nakai cv. ‘Ingrid’]
either ungrafted or grafted onto the four commercial rootstocks: ‘Macis’, ‘Argentario’[Lagenaria siceraria
(Mol.) Standl.] and ‘P360’, ‘PS1313’ (Cucurbita maxima Duchesne×Cucurbita moschata Duchesne) grown
in a closed-loop system. Plants were supplied with nutrient solutions having two levels of pH (6.0 or
8.1). The high pH nutrient solution had the same basic composition plus an additional of 10mMNaHCO3
and 0.5 g L−1 CaCO3. Significant depression of shoot, root biomass production, and leaf macro- (N, P, K,
and Mg) and microelements (Fe, Mn, Zn, and Cu) under high pH level was observed in both grafted and
ungrafted plants. Increasing the concentration of NaHCO3 from 0 to 10mMin the nutrient solution significantly
enhanced FCR activity of root tips to 2.3 times in high pH treatment in comparison to the control.
At high pH level, the percentage of shoot biomass weight reduction was significantly lower in plants
grafted onto pumpkins rootstocks in comparison to those grafted onto the bottle gourd rootstocks and
the ungrafted plants. Moreover, at high pH level, the highest percentage of root biomass weight reduction
was recorded in both grafting combinations ‘Ingrid/P360’ and ‘Ingrid/Macis’. The high pH-related
reduction in net assimilation was more severe in ungrafted plants in comparison with the grafted ones.
The Fe concentration in leaves was significantly higher in plants grafted onto pumpkin rootstocks (avg.
109.5gg−1) in comparison to that of bottle gourd rootstocks and ungrafted plants (avg. 86.7gg−1).
For plants grafted onto bottle gourd rootstocks and ungrafted plants the high pH level (8.1) in the nutrient
solution caused significant decrease in macronutrient leaf concentration especially for P and Mg
compared to plants grafted onto pumpkin rootstocks. Increasing the nutrient solution pH from 6.0 to 8.1
increased exudation of organic acids (citric, malic, tartaric and succinic acids). Watermelon plants grafted
onto pumpkin rootstocks exuded more citric and malic acids than those grafted onto bottle gourd rootstocks
and ungrafted plants especially under bicarbonate-enriched conditions. These results support the
hypothesis that uptake of nutrients (e.g. P, Mg, and Fe) from the nutrient solution by pumpkin rootstocks
was facilitated by exudation of organic acids from roots
Role of grafting in vegetable crops grown under saline conditions
No full textSalinity isoneofthemajorabioticstressesthatreduceplantgrowthandcropproductivityinmanyveg-
etable productionareasoftheworld.Graftingcanrepresentaninterestingtooltoavoidorreduceyield
losses causedbysalinitystressinhigh-yieldinggenotypesbelongingto Solanaceae and Cucurbitaceae
families. Graftingisanintegrativereciprocalprocessand,therefore,bothscionandrootstockcaninflu-
ence salttoleranceofgraftedplants.Graftedplantsgrownundersalineconditionsoftenexhibitedbetter
growth andyield,higherphotosynthesisandleafwatercontent,greaterroot-to-shootratio,higheraccu-
mulation ofcompatibleosmolytes,abscisicacidandpolyaminesinleaves,greaterantioxidantcapacity
in leaves,andloweraccumulationofNa+ and/or Cl− in shootsthanungraftedorself-graftedplants.
This reportgivesanoverviewoftherecentliteratureonthesalinityresponseofgraftedplantsandthe
mechanisms ofsalttoleranceingraftedplantsrelatedtothemorphologicalrootcharacteristicsandthe
physiological andbiochemicalprocesses.Thereviewwillconcludebyidentifyingseveralprospectsfor
future researchesaimingtoimprovetheroleofgraftinginvegetablecropsgrownundersalineconditions
Grafting cucumber plants enhance tolerance to sodium chloride and sulfate salinization
No full textThe aim of the current work was to determine whether grafting could improve salinity tolerance of
cucumber using two different salt stressors such as NaCl and Na2SO4 with equimolar concentrations,
and to study the changes induced by the rootstock in the shoot growth at agronomical and physiological
levels. A greenhouse experiment was carried out to determine yield, growth, fruit quality, leaf gas
exchange, electrolyte leakage, SPAD, and mineral composition and assimilate partitioning of cucumber
plants (Cucumis sativus L. cv. ???Akito???), either ungrafted or grafted onto the commercial rootstock
???PS1313??? (Cucurbita maxima Duch.
×
Cucurbita moschata Duch.) and cultured in quartziferous sand. Plants
were supplied with three nutrient solutions: non-salt control, 27 mM Na2SO4, or 40 mM NaCl. Significant
depression of yield, shoot and root biomass production in response to an increase of salinity concentration
in the nutrient solution was observed with more detrimental effects with NaCl treatment. The two
salt treatments, especially NaCl, inhibited photosynthesis, pigment synthesis, and membrane integrity.
Salinity with NaCl and Na2SO4 improved fruit quality in both grafting combinations by increasing fruit dry
matter and total soluble solids content. Moreover, at the two salt treatments the percentage of yield and
biomass reduction in comparison to control was significantly lower in the plants grafted onto ???PS1313???
than ungrafted plants, with the highest yield, shoot and root reduction recorded with NaCl in comparison
to those recorded with Na2SO4 treatment. Grafted cucumber plants exposed to Na2SO4 were capable of
maintaining higher net assimilation rates, higher chlorophyll content (SPAD index), a better nutritional
status (higher K, Ca and Mg and lower Na) in the shoot tissues and higher membrane selectivity in comparison
with ungrafted ones. The higher crop performance of grafted cucumber recorded with Na2SO4
than with NaCl, was attributed to the inability of the rootstock to restrict Cl??? shoot uptake, thus Cl???, which
continues passing to the leaves, becomes the more significant toxic component of the saline solution
Amelioration of heavy metal and nutrient stress in fruit vegetables by grafting
No full textThe responseofgraftedvegetablestostressconditionsowingtothenutrientstatus,andthepresenceof
heavy metalsintherootenvironmentmaybedifferentthanthatofself-rootedplants,dependingmainly
on therootstockgenotype.Severalstudieshaveindicatedthatsomerootstocksarecapableofrestricting
the uptakeand/orthetransportofheavymetals(e.g.Cd,Ni,Cr)andmicronutrients(e.g.Cu,BandMn)to
the shoot,therebymitigatingthestresscausedbyexcessiveexternalconcentrationsofthem.However,
other mechanismsdrivenbytherootsystem,suchasdetoxificationofharmfulelementsorhormonal
signals modifyinggeneexpressioninthescion,seemtobeinvolvedinthemitigationofstresscaused
by excessiveexternalnutrientorheavymetalconcentrations.Ontheotherhand,theuptakeand/or
utilization efficiencyofmacronutrients(N,P,K,CaandMg)byplantsmaybeenhancedbygraftingonto
some rootstocks.Thisisascribedmainlytotherootcharacteristicsoftheserootstocks,whicharemore
vigorous thanthoseofhighlyproductivecultivatedvarieties.However,othermechanismsimplicatedin
the efficiencyofactivenutrientabsorptionbytheroots,aswellassignalsarisingfromthescion,which
are mainlygovernedbysinkdemand,mayalsoenhancenutrientuptakeandutilization.Thehigher
efficiency ofsomegraftcombinationsoffruitvegetablestotakeupandutilizenutrientsmaymitigate
yield lossesowingtoshortagesofthesenutrientsintherootenvironmentofplantsandrestrictnutrient
losses duetoleaching.Nevertheless,itisimportanttospecificallytesteachgraftingcombinationand
not merelyeachrootstockforitsabilitytoamelioratenutrientorheavymetalstressbecauseinmany
instances theresponsesdependontherootstock/scioncombination.Thisreportgivesanoverviewon
the prospectsandrestrictionsofgraftingasameanstominimizethenegativeeffectsofheavymetals,
excessive nutrientavailability,nutrientdeficiency,andalkalinitystressonvegetablecropperformance
taking intoconsiderationagronomical,physiologicalandbiochemicalaspects
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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