net photosynthesis (a) of bell pepper during peak drought
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Net photosynthesis (A) of bell pepper Net photosynthesis (A) of bell pepper during peak drought & recoveryduring peak drought & recovery
AMF Enhancement of Drought StressAMF Enhancement of Drought Stress--Bell PepperBell Pepper
AMF Peppers have:AMF Peppers have:Leaf ChlorophyllLeaf Chlorophyll
Stomatal ConductanceStomatal Conductance
PhotosynthesisPhotosynthesis
Osmotic AdjustmentOsmotic Adjustment
Faster Drought RecoveryFaster Drought Recovery
Phosphorus & plant size Phosphorus & plant size not not the limiting factorthe limiting factor
AMF Pepper Plants have:AMF Pepper Plants have:••Greater Extraradical Hyphae formationGreater Extraradical Hyphae formation
••Greater Soil AggregationGreater Soil Aggregation
•Improved Soil Tilth
•Glomalin – hydrophobic protein
→→ Not all mycorrhiza respond equally to droughtNot all mycorrhiza respond equally to drought
Chile ancho pepper: Chile ancho pepper:
••Glomus fasciculatumGlomus fasciculatum (Trappe, Oregon) (Trappe, Oregon)
••ZACZAC--1919: : mixed mixed Glomus Glomus species: species: G. albidiumG. albidium, , G. claroidesG. claroides, , G. diaphamumG. diaphamum
(Zacatecas, Mexico; 450 mm annual Precipitation; (Zacatecas, Mexico; 450 mm annual Precipitation; Chamizo, FerreraChamizo, Ferrera--Cerrato, 1998)Cerrato, 1998)
AMF Drought Soil Moist.(%)
ψleaf
(-Mpa)
gs
(mmol m-2
s-1)
RWC
(%)
Whole Plant Transpiration(mg H2O
m-2 s-1)
WUE(10-3. g. kg-1)
∆(‰)
Control No 17.0±1.4 0.1±0 268±14 92.6±1.4 48.2±1.4 5.34 18.9G. fasc. 18.3±0.4 0.1±0 257±13 88.9±1.1 48.1±1.4 5.29 18.7
ZAC-19 18.8±0.2 0.1±0 233±19 93.0±1.9 46.7±2.1 5.09 18.8
Control Yes 3.9±0.1 0.7±0.1 57±7 80.2±3.4 30.1±1.7 5.55 19.1G. fasc. 3.8±0.1 0.8±0.1 46±4 79.3±1.0 27.1±1.6 5.68 19.2
ZAC-19. 4.1± 0.4 0.2±0 51±4 84.4±1.9 25.4±1.9 5.58 19.2
SignificanceAMF NS 0.0001 NS NS NS NS NSDrought (D) 0.0001 0.0001 0.0001 0.0001 0.0001 NS NSAMF X (D) NS 0.0001 NS NS NS NS NS
Chile Ancho pepper plants during peak drought stress (day 20).Chile Ancho pepper plants during peak drought stress (day 20).
AMF Drought % Plantsnot wilted
% Plants moderatelywilted
% Plantsseverely wilted
Control Yes 0±0 47±12. 53±12
G. fasc. 0±0 26±10 74±10ZAC-19. 0±0 79±10 21±11
SignificanceAMF NS 0.0026 0.0089Drought (D) 0.0001 0.0001 0.0001AMF x D NS 0.0026 0.0089
Wilting of Chile Ancho pepper plants Wilting of Chile Ancho pepper plants ---- peak drought stress (day 20).peak drought stress (day 20).
Effect of Drought Stress on Colonization of Chile Ancho pepperEffect of Drought Stress on Colonization of Chile Ancho pepper
Control Glomus Glomus fasciculatumfasciculatum ZacZac--1919
DroughtDrought
NoNo 00 56.4a56.4a 37.5b
YesYes 00 21.6b21.6b 43.0a
(Pr>F)(Pr>F) NSNS 0.00010.0001 NSNS
DroughtDrought
NoNo 00 81.4a81.4a 29.9
YesYes 00 42.8b42.8b 26.1
(Pr>F)(Pr>F) NSNS 0.00010.0001 NSNS
DroughtDrought
NoNo 00 90.2a90.2a 51.9b
YesYes 00 62.7b62.7b 59.9a
(Pr>F)(Pr>F) NSNS 0.00010.0001 0.0030.003
% Arbuscule Formation
% Vesicle Formation
% Total Root Colonization
Table 2.Table 2. Growth parameters of mycorrhizal (AMF) and NonGrowth parameters of mycorrhizal (AMF) and Non--VAM VAM neem plants at the end of the drought stress cycle neem plants at the end of the drought stress cycle (23 days of drought followed (23 days of drought followed by a 1 day recovery).by a 1 day recovery).
AMF AMF DroughtDroughtacclimationacclimation
LeafLeafNo.No.
Leaf Leaf areaarea
Plant dry mass (g)Plant dry mass (g) Root/Root/shootshootratioratio
(m(m22))LeafLeaf(g) (g)
StemStem(g)(g)
RootRoot(g)(g) (g.g(g.g--11))
NonAMFNonAMF
AMFAMF
SignificanceSignificanceAMFAMFDroughtDroughtAMF x DAMF x D
NoNoYesYesNoNoYesYes
2929±±222121±±222929±±222323±±22
NSNS****NSNS
0.200.20±±0.010.010.140.14±±0.010.010.200.20±±0.010.010.140.14±±0.010.01
NSNS****
NSNS
1818±±111111±±111818±±111212±±11
NSNS****
NSNS
1111±±1188±±11
1111±±0099±±11
NSNS****
NSNS
1111±±1199±±00
1212±±1199±±00
NSNS****
NSNS
0.380.38±±0.030.030.470.47±±0.030.030.400.40±±0.020.020.430.43±±0.030.03
NSNS****
NSNS
AMF Effects on Neem Tree SeedlingsAMF Effects on Neem Tree Seedlings
±± AMF neem trees of similar size and nutrition respond to drought AMF neem trees of similar size and nutrition respond to drought similarly.similarly.
Neem drought response: decrease in leaf area, gas exchange rate Neem drought response: decrease in leaf area, gas exchange rate and water and water relations parameters. relations parameters.
Rapid recovery after rehydration with an acclimation of stomatalRapid recovery after rehydration with an acclimation of stomatal conductance.conductance.
Water Use EfficiencyWater Use Efficiency
Dry Mass gain per total water usage Dry Mass gain per total water usage ––(g Carbon/kg H(g Carbon/kg H22O) O) [Long Term][Long Term]
Gas Exchange: net Photosynthesis/ stomatal Gas Exchange: net Photosynthesis/ stomatal conductance conductance ((AA) / () / (ggss) ) [Instantaneous][Instantaneous]