scholarly journals Variation in scion water relations mediated by two newly released Geneva series rootstocks

2021 ◽  
Author(s):  
Erica Casagrande Biasuz ◽  
Lee Kalcsits

Dwarfing rootstocks are used to control tree vigor allowing for increased densities that increase apple production. Although there is considerable variation among rootstocks in dwarfing capacity, the mechanisms by which rootstocks affect vigor in apple scions remains unclear. Here, Honeycrisp apple growth and water relations were compared among three rootstocks; M-9 as the industry standard and two less studied Geneva series rootstocks; G.87 and G. 814 in Washington, USA. Trees were acquired from a commercial nursery and planted in 2017. In 2018 and 2019, scion physiological, isotopic and morphological traits were measured to better understand the link between rootstock-driven vigor and physiological traits. Rootstock affected scion shoot growth (P <0.001), stomatal conductance (P< 0.01) and stem water potential (P <0.001). Rootstocks with low vegetative vigor like M.9 also had lower stomatal conductance and enriched leaf δ13C and δ18O isotope composition. Plant growth was positively correlated with stomatal conductance and stem water potential. Rootstocks also affected plant water status and net gas exchange. Here, we report an association between rootstock-induced vigor and scion physiological traits such as gas exchange, stem water potential, and leaf carbon and oxygen isotope composition. This research has implications for the understanding of the mechanisms of dwarfing by rootstocks in apple.

Author(s):  
Erica Casagrande Biasuz ◽  
Lee Kalcsits

Composite trees combine traits from both the rootstock and scion. Dwarfing rootstocks are used to reduce shoot vigor and improve fruit quality and productivity. Although differences in rootstock vigour have been clearly described, the underlying physiological mechanisms regulating scion vigor are not well understood. Plant water status is strongly influenced by stem hydraulic resistance to water movement. In the scion, stomata regulate transpiration rates and are essential to prevent hydraulic failure. Lower stomatal conductance contributes to enriched leaf carbon isotope composition (δ13C). Combined, the effects of increased hydraulic resistance, limited stomatal control, and subsequently, limited gas exchange can affect tree growth. These differences may also correspond to differences in scion vigor. Here, vegetative growth, gas exchange, stem water potential, and leaf δ13C were compared to determine how rootstocks affect scion water relations. B.9 had the lowest shoot vigor compared to the more vigorous rootstock, G.890. Similarly, photosynthetic rates were also lower. Rootstock vigor was closely associated with leaf gas exchange and stem water potential in the scion and were reflected in leaf δ13C signatures. Dwarfing was strongly related to hydraulic limitations induced by rootstock genotype and these changes are distinguishable when measuring leaf and stem δ13C composition.


2011 ◽  
Vol 38 (5) ◽  
pp. 372 ◽  
Author(s):  
Gregorio Egea ◽  
Ian C. Dodd ◽  
María M. González-Real ◽  
Rafael Domingo ◽  
Alain Baille

To determine whether partial rootzone drying (PRD) optimised leaf gas exchange and soil–plant water relations in almond (Prunus dulcis (Mill.) D.A. Webb) compared with regulated deficit irrigation (RDI), a 2 year trial was conducted on field-grown trees in a semiarid climate. Five irrigation treatments were established: full irrigation (FI) where the trees were irrigated at 100% of the standard crop evapotranspiration (ETc); three PRD treatments (PRD70, PRD50 and PRD30) that applied 70, 50 and 30% ETc, respectively; and a commercially practiced RDI treatment that applied 50% ETc during the kernel-filling stage and 100% ETc during the remainder of the growth season. Measurements of volumetric soil moisture content in the soil profile (0–100 cm), predawn leaf water potential (Ψpd), midday stem water potential (Ψms), midday leaf gas exchange and trunk diameter fluctuations (TDF) were made during two growing seasons. The diurnal patterns of leaf gas exchange and stem water potential (Ψs) were appraised during the kernel-filling stage in all irrigation regimes. When tree water relations were assessed at solar noon, PRD did not show differences in either leaf gas exchange or tree water status compared with RDI. At similar average soil moisture status (adjudged by similar Ψpd), PRD50 trees had higher water status than RDI trees in the afternoon, as confirmed by Ψs and TDF. Although irrigation placement showed no effects on diurnal stomatal regulation, diurnal leaf net photosynthesis (Al) was substantially less limited in PRD50 than in RDI trees, indicating that PRD improved leaf-level water use efficiency.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 857B-857
Author(s):  
Rashid Al-Yahyai* ◽  
Bruce Schaffer ◽  
Frederick S. Davies

The effect of soil water depletion on plant water potential and leaf gas exchange of carambola (Averrhoa carambola L. cv. Arkin) in Krome very gravelly loam soil was studied in an orchard and in containers in the field and in a greenhouse. The rate of soil water depletion was determined by continuously monitoring soil water content with multi-sensor capacitance probes. Stem water potential and leaf gas exchange of carambola in containers were reduced when the soil water depletion level fell below 50% (where field capacity = 100%). Although there was a decrease in the rate of soil water depletion in the orchard as the soil dried, soil water depletion did not go below an average of 70%. This was presumably due to sufficient rainfall and capillary movement of water in the soil. Therefore, soil water content did not decline sufficiently to affect leaf gas exchange and leaf and stem water potential of orchard trees. A decline in soil water depletion below 40% resulted in a concomitant decline in stem water potential of the container trees in the field and greenhouse to below -1.0 MPa. Stomatal conductance, net CO2 assimilation, and transpiration declined significantly when stem water potential was below -1.0 MPa. The reduction of net CO2 assimilation and transpiration was proportional to the decline in stomatal conductance of container trees in the field and greenhouse. Thus, soil water depletion in Krome very gravelly loam soil must be less than 50% before water potential or leaf gas exchange of carambola is affected. Based on these results, irrigation scheduling should be based on physiological variables such as stem water potential and stomatal conductance or the amount rather than the rate of soil water depletion.


2005 ◽  
Vol 85 (4) ◽  
pp. 919-927 ◽  
Author(s):  
V. M. Glass ◽  
D. C. Percival ◽  
J. T.A. Proctor

A 2-yr field study examining the effect of soil moisture on plant water status, photosynthesis and gas exchange parameters in lowbush blueberry (Vaccinium angustifolium Ait.) was conducted at the Nova Scotia Wild Blueberry Institute (NSWBI), Debert, NS. Drought and irrigation treatments were applied over two years in either or both the vegetative and cropping years of production. Midday stem water potential values indicated that all treatments resulted in drought stress. Mean stem water potential values ranged from -1.41 to -1.45 MPa. Predawn stem water potentials in the vegetative growth season indicated that although some recharging and recovery of water loss occurred overnight, the drought-stressed plants did not fully return to pre-stress levels under the moisture-limiting conditions. Higher chlorophyll a and b levels were observed in the single-season drought treatment. Leaves of irrigated plants in both sprout and crop years had the highest stomatal density. There were no differences in photosynthetic rate (Pn) among treatments despite the lower stomatal conductance resulting from limited soil moisture. Key words: Photosynthesis, stomate, stem water potential


Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3596 ◽  
Author(s):  
Marcos Carrasco-Benavides ◽  
Javiera Antunez-Quilobrán ◽  
Antonella Baffico-Hernández ◽  
Carlos Ávila-Sánchez ◽  
Samuel Ortega-Farías ◽  
...  

The midday stem water potential (Ψs) and stomatal conductance (gs) have been traditionally used to monitor the water status of cherry trees (Prunus avium L.). Due to the complexity of direct measurement, the use of infrared thermography has been proposed as an alternative. This study compares Ψs and gs against crop water stress indexes (CWSI) calculated from thermal infrared (TIR) data from high-resolution (HR) and low-resolution (LR) cameras for two cherry tree cultivars: ‘Regina’ and ‘Sweetheart’. For this purpose, a water stress–recovery cycle experiment was carried out at the post-harvest period in a commercial drip-irrigated cherry tree orchard under three irrigation treatments based on Ψs levels. The water status of trees was measured weekly using Ψs, gs, and compared to CWSIs, computed from both thermal cameras. Results showed that the accuracy in the estimation of CWSIs was not statistically significant when comparing both cameras for the representation of Ψs and gs in both cultivars. The performance of all evaluated physiological indicators presented similar trends for both cultivars, and the averaged differences between CWSI’s from both cameras were 11 ± 0.27%. However, these CWSI’s were not able to detect differences among irrigation treatments as compared to Ψs and gs.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 648d-648
Author(s):  
A. Naor ◽  
Y. Gal ◽  
B. Bravdo

The effect of shoot density and crop level on gas exchange and water relations of filed-grown Sauvignon blanc was studied. Ten and 44 shoots/vine and one and two clusters per shoot treatments were examined in a factorial design. The two-cluster treatments had higher stem water potential (Ystem), assimilation rate, and stomatal (gs) and nonstomatal (gm) conductance. A quantitative analysis suggests that capacitance cannot account for the simultaneous increase in gs and Ystem in the two clusters treatment. The two-cluster treatment had higher Ystem for similar transpiration rates (similar gs) compared to the one-cluster treatment. The similar transpiration rate and lower stem to root water potential difference in the two-cluster treatment was explained by increased root permeability in the two-cluster treatment. The similar gs–gm, in spite of a meaningful decrease of gs with decreasing Ystem, suggests that gs and gm synchronize themselves to perturbations of gm due to sink effect and gs due to water stress.


2014 ◽  
Vol 139 (5) ◽  
pp. 537-546 ◽  
Author(s):  
Yahia Othman ◽  
Dawn VanLeeuwen ◽  
Richard Heerema ◽  
Rolston St. Hilaire

Demand for New Mexico’s limited water resources coupled with periodic drought has increased the necessity for tree water status monitoring to guide irrigation scheduling of pecan (Carya illinoinensis) orchards. The objectives of this study were to assess the impact of water status developed during the flood irrigation dry-down cycles on photosynthesis (Pn), and gas exchange [stomatal conductance (gS) to H2O (gH2O), transpiration (E), and intercellular CO2 (ci)] and to establish values of midday stem water potential (Ψsmd) that are needed to maintain Pn and gas exchange of pecan. We conducted the study simultaneously on two southern New Mexico mature pecan orchards from 2011 through 2013. Flood irrigation as determined by grower practice was used on both orchards and Pn, gH2O, E, and ci were assessed at Ψsmd of –0.4 to –2.0 MPa. Photosynthesis and gas exchange were higher in pecan trees shortly after irrigation than trees exhibiting water deficit near the end of a flood irrigation dry-down cycle. The decline in Pn was markedly noticeable when Ψsmd dropped below –0.9 MPa. We attributed the reduction in Pn mostly to stomatal limitation. The decline in Pn and gH2O exceeded 50% when Ψsmd ranged from –1.5 to –2.0 MPa. For those reasons, we recommended that pecan orchards be maintained at Ψsmd higher than –0.90 MPa to prevent significant reductions in carbon assimilation and gas exchange.


2021 ◽  
Vol 13 (9) ◽  
pp. 1837
Author(s):  
Eve Laroche-Pinel ◽  
Sylvie Duthoit ◽  
Mohanad Albughdadi ◽  
Anne D. Costard ◽  
Jacques Rousseau ◽  
...  

Wine growing needs to adapt to confront climate change. In fact, the lack of water becomes more and more important in many regions. Whereas vineyards have been located in dry areas for decades, so they need special resilient varieties and/or a sufficient water supply at key development stages in case of severe drought. With climate change and the decrease of water availability, some vineyard regions face difficulties because of unsuitable variety, wrong vine management or due to the limited water access. Decision support tools are therefore required to optimize water use or to adapt agronomic practices. This study aimed at monitoring vine water status at a large scale with Sentinel-2 images. The goal was to provide a solution that would give spatialized and temporal information throughout the season on the water status of the vines. For this purpose, thirty six plots were monitored in total over three years (2018, 2019 and 2020). Vine water status was measured with stem water potential in field measurements from pea size to ripening stage. Simultaneously Sentinel-2 images were downloaded and processed to extract band reflectance values and compute vegetation indices. In our study, we tested five supervised regression machine learning algorithms to find possible relationships between stem water potential and data acquired from Sentinel-2 images (bands reflectance values and vegetation indices). Regression model using Red, NIR, Red-Edge and SWIR bands gave promising result to predict stem water potential (R2=0.40, RMSE=0.26).


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