scholarly journals Screening of ‘King’ Mandarin Hybrids as Tolerant Citrus Rootstocks to Flooding Stress

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 388
Author(s):  
Mary-Rus Martínez-Cuenca ◽  
Amparo Primo-Capella ◽  
María Ángeles Forner-Giner

This work compares the tolerance to long-term anoxia conditions (35 days) of five new citrus ‘King’ mandarin (Citrus nobilis L. Lour) × Poncirus trifoliata ((L.) Raf.) hybrids (named 0501XX) and Carrizo citrange (CC, Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.), the widely used citrus rootstock in Spain. Growth parameters, chlorophyll concentration, gas exchange and fluorescence parameters, water relations in leaves, abscisic acid (ABA) concentration, and PIP1 and PIP2 gene expressions were assessed. With a waterlogging treatment, the root system biomass of most hybrids went down, and the chlorophyll a and b concentrations substantially dropped. The net CO2 assimilation rates (An) and stomatal conductance (gs) lowered significantly due to flooding, and the transpiration rate (E) closely paralleled the changes in gs. The leaf water and osmotic potentials significantly increased in most 0501 hybrids. As a trend, flooding stress lowered the ABA concentration in roots from most hybrids, but increased in the leaves of CC, 05019 and 050110. Under the control treatment (Ct) conditions, most 0501 hybrids showed higher PIP1 and PIP2 expressions than the control rootstock CC, but were impaired due to the flooding conditions in 05019 and 050110. From this study, we conclude that 0501 genotypes develop some adaptive responses in plants against flooding stress such as (1) stomata closure to prevent water loss likely mediated by ABA levels, and (2) enhanced water and osmotic potentials and the downregulation of those genes regulating aquaporin channels to maintain water relations in plants. Although these traits seemed especially relevant in hybrids 050110 and 050125, further experiments must be done to determine their behavior under field conditions, particularly their influence on commercial varieties and their suitability as flooding-tolerant hybrids for replacing CC, one of the main genotypes that is widely used as a citrus rootstock in Spain, under these conditions.

Botany ◽  
2008 ◽  
Vol 86 (11) ◽  
pp. 1242-1251 ◽  
Author(s):  
Zoubeir Béjaoui ◽  
Ali Albouchi ◽  
Mohammed S. Lamhamedi ◽  
Mohamed Hédi El Aouni

Tunisia has vast land tracts that are marginal, arid, semiarid, or desert (about three quarters of the surface of the country). Reforestation of these regions is one of the methods being used to rehabilitate degraded areas. Casuarina glauca Sieber, a fast-growing tree species that is widely used outside of its native range, was tested in the present study with respect to its degree of acclimatization and hardening in response to drought. Three water regimes, simulating the conditions of the reforestation sites, were applied to C. glauca seedlings. These regimes included a control treatment (T : predawn water potential Ψb = –0.2 MPa), a moderate stress treatment (M : Ψb = –0.5 MPa), and a severe stress treatment (S : Ψb = –1.0 MPa). Water relations parameters, estimated by pressure–volume curves through a repeat pressurization method, as well as accumulated dry mass were measured at the beginning of the experiment and 2, 4, and 6 months following treatment imposition. The total dry mass of M and S plants was significantly affected by the treatments. However, water stress favoured dry mass allocation to roots and decreased the shoot turgid mass / dry mass ratio (TM/DM). The evolution of water relations parameters under M or S regimes revealed an adaptive capacity of C. glauca seedlings, as expressed by a significant decrease of the osmotic potentials at full turgor (Ψπ100) and at the turgor loss point (Ψπ0), an osmotic adjustment in water-stressed plants reaching 0.31 and 0.56 MPa, and a significant increase in εmax reaching 26 % and 68 % of that of the control plants, respectively, at the end of the drought period. A reduction in shoot TM/DM combined with increases in εmax during water stress suggests the presence of a cell wall adjustment. These effects were more pronounced under the severe stress. Our results suggest that preconditioning seedlings to drought under nursery conditions by applying a moderate or severe stress, depending on the conditions of the planting site, for 4 months prior to outplanting, possibly will allow the seedlings to adapt morphologically and physiologically and improve their chance of survival in arid and semiarid zones.


HortScience ◽  
1994 ◽  
Vol 29 (2) ◽  
pp. 113-116 ◽  
Author(s):  
◽  
D.H. Byrne ◽  
R.E. Rouse

Eighteen citrus rootstock seedling lines were tested for their tolerance to Fe chlorosis using sand culture. Potassium carbonate was used to induce Fe-deficiency chlorosis. Chlorosis was quantified by 1) visual ratings, 2) SPAD-502 chlorophyll meter readings, 3) leaf chlorophyll concentration, 4) leaf active Fe, and 5) leaf total Fe. The first four criteria were well correlated among each other but not with leaf total Fe. Although any of the first four measurements could be used to quantify chlorosis, visual ratings and SPAD-502 readings were more convenient. The rootstock that have been reported to be tolerant or very susceptible to Fe chlorosis in calcareous soils were rated similarly for tolerance to bicarbonate-induced Fe chlorosis. Nontrifoliate types such as Texas sour orange (C. aurantium L.), Cleopatra mandarin (C. reticulata Blanco), Vangasay lemon (C. limon Burro.), and Ridge pineapple x Milam 1578-201 (C. sinensis L. Osbeck x C. jambhiri) were tolerant to moderately tolerant. Although most of the trifoliate hybrids tested were moderately susceptible to very susceptible, Smooth Seville x Argentine trifoliate {[C. grands (L.) Osbeck x C. aurantium] x Poncirus trifoliata (L.) Raf.} and F-81-12 citrange (C. sinensis x P. trifoliata) exhibited relatively high tolerance to lime-induced Fe chlorosis.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1388
Author(s):  
Hang Yin ◽  
Junxiu Wang ◽  
Yao Zeng ◽  
Xinjian Shen ◽  
Yizhong He ◽  
...  

Rare earth elements (REEs) can affect the growth and development of plants. However, few studies have been carried out on the effects of REEs on citrus seedlings. In this study, the growth parameters, toxicity symptoms, chlorophyll content, and La content of three citrus rootstocks are analyzed under different concentrations of La, a representative REE. The results show that the growth of citrus rootstock seedlings was stimulated at La ≤ 0.5 mmol·L−1 and inhibited at concentrations above 1 mmol·L−1. The chlorophyll and carotenoid contents of trifoliate orange (Poncirus trifoliata L. Raf.) and Ziyang Xiangcheng (C. junos Sieb. ex Tanaka) leaves of plants grown at low concentrations of La (≤1.5 mmol·L−1) were similar to those of the control but were significantly reduced at 4 mmol·L−1 La. Toxic symptoms gradually appeared with increasing La concentrations, with yellowed leaves and burst veins appearing at 4 mmol·L−1 La. The symptoms of toxicity were most severe in trifoliate orange, followed by Shatian Pomelo (Citrus grandis var. shatinyu Hort) and then Ziyang Xiangcheng. Moreover, in leaves, the Ca content was significantly negatively correlated with La content (p < 0.01). These results indicate that La has a hormesis effect on the growth of citrus rootstocks. Of the studied citrus seedlings, Ziyang Xiangcheng is the most resistant to La.


2021 ◽  
Vol 13 (5) ◽  
pp. 2477
Author(s):  
Kleopatra-Eleni Nikolaou ◽  
Theocharis Chatzistathis ◽  
Serafeim Theocharis ◽  
Anagnostis Argiriou ◽  
Stefanos Koundouras ◽  
...  

Under the current and future climate crisis, a significant rise in soil salinity will likely affect vine productivity in several Mediterranean regions. During the present research, the rootstock effects on salinity tolerance of Merlot and Cabernet Franc grapevine cultivars were studied. In a pot hydroponic culture, own-rooted Merlot and Cabernet Franc grapevine cultivars or grafted onto the rootstocks 1103 P and 101-14 Mgt were drip-irrigated with saline water. A completely randomized 3 × 2 × 2 factorial experiment was designed with two vine rootstocks or own-rooted vines, two scion cultivars, and 100 mM NaCl salinity or control treatments, with six replications. A significant effect of scion cultivar, rootstock, and salinity was observed for most of the measured parameters. At the end of salinity stress period, leaf, shoot, root, and trunk nutrient concentrations were measured. Salinity stress increased Chloride (Cl−) and Sodium (Na+) concentrations in all parts of the vines and decreased leaf concentrations of Potassium (K+), Calcium (Ca+2), Magnesium (Mg+2), Nitrogen (N), and Iron (Fe). In contrast, salinity stress increased leaf Boron (B) concentrations, whereas that of Manganese (Mn) remained unaffected. Leaf chlorophyll concentration decreased from 42% to 40% after thirty and sixty days of salt treatment, respectively. A similar trend was observed for the CCM-200 relative chlorophyll content. Salinity significantly decreased steam water potential (Ws), net CO2 assimilation rate (A), and stomatal conductance(gs) in all cases of grafted or own-rooted vines. Sixty days after the beginning of salt treatment, total Phenolics and PSII maximum quantum yield (Fv/Fm) decreased significantly. The rootstock 1103 P seems to be a better excluder for Na+ and Cl− and more tolerant to salinity compared to 101-14 Mgt rootstock.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yue Huang ◽  
Yuantao Xu ◽  
Xiaolin Jiang ◽  
Huiwen Yu ◽  
Huihui Jia ◽  
...  

AbstractGrafting is an ancient technique used for plant propagation and improvement in horticultural crops for at least 1,500 years. Citrus plants, with a seed-to-seed cycle of 5–15 years, are among the fruit crops that were probably domesticated by grafting. Poncirus trifoliata, a widely used citrus rootstock, can promote early flowering, strengthen stress tolerance, and improve fruit quality via scion–rootstock interactions. Here, we report its genome assembly using PacBio sequencing. We obtained a final genome of 303 Mb with a contig N50 size of 1.17 Mb and annotated 25,680 protein-coding genes. DNA methylome and transcriptome analyses indicated that the strong adaptability of P. trifoliata is likely attributable to its special epigenetic modification and expression pattern of resistance-related genes. Heterografting by using sweet orange as scion and P. trifoliata as rootstock and autografting using sweet orange as both scion and rootstock were performed to investigate the genetic effects of the rootstock. Single-base methylome analysis indicated that P. trifoliata as a rootstock caused DNA demethylation and a reduction in 24-nt small RNAs (sRNAs) in scions compared to the level observed with autografting, implying the involvement of sRNA-mediated graft-transmissible epigenetic modifications in citrus grafting. Taken together, the assembled genome for the citrus rootstock and the analysis of graft-induced epigenetic modifications provide global insights into the genetic effects of rootstock–scion interactions and grafting biology.


1987 ◽  
Vol 104 (1) ◽  
pp. 37-43 ◽  
Author(s):  
U. Hartmond ◽  
N. V. Schaesberg ◽  
J. H. Graham ◽  
J. P. Syvertsen

Author(s):  
Gamze Kaya

The study aimed to evaluate the use of germination indices as a screening tool for salinity tolerance during germination and early seedling growth of pepper cultivars, and to distinguish the potential for genetic responses to salt tolerance. In the study, the seeds of seven pepper cultivars were germinated at increasing NaCl levels of 5, 10, 15 and 20 dS/m and distilled water as the control treatment for 14 days. Germination percentage (GP), mean germination time (MGT), germination index (GI), germination stress tolerance index (GSTI), seedling length (SL), seedling fresh weight (SFW) and vigor index (VI) were investigated. Results showed that germination percentage decreased with increasing NaCl levels while the highest germination percentage at 20 dS/m was 92% in BT Burdem with no significant reduction. Seedling growth of pepper cultivars was severely inhibited by increasing salinity stress. SFW was depressed depending on reduction in SL due to increasing NaCl. BT-Burli and BT İnce Sivri were the most tolerant cultivars to NaCl and they were used for genetic resources towards salinity. Seedling growth was much more sensitive to salinity than germination because of the highest percent reduction in seedling growth parameters. Among the parameters, GSTI gave the highest significant correlation coefficient with SL and SFW; indicating that it would be useful for estimating seedling growth. It was concluded that genotypic variation was observed among pepper cultivars for salinity tolerance and GSTI could be used for a predictor for salinity tolerance.


Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1087
Author(s):  
Muhammad Israr ◽  
Naila Chand ◽  
Rifat Ullah Khan ◽  
Ibrahim A. Alhidary ◽  
Mutassim M. Abdelrahman ◽  
...  

A total of 300 day old broiler chicks (Hubbard) were assigned to 30 floor pens (10 birds per pen) under cyclic heat stress. Three diets including a control, as well as two levels of grape seed powder (GSP) and zinc (OZ) at the rates of 2.5 g/kg GSP + 50 mg/kg OZ and 5 g/kg GSP + 50 mg/kg OZ, were supplied to the broilers for 35 days. According to the results, broiler feed intake improved (p < 0.05) in GSP + OZ groups from 3–5 weeks and on an overall basis compared to the control diet. Body weight increased (p < 0.05) in GSP-5 + OZ-50 during weeks 2–5 and on an overall basis. The findings indicated that feed conversion ratio (FCR) decreased (p < 0.05) during week 5 in broilers supplemented with GSP-5 + OZ-50. The antibody titer (HI) against Newcastle disease (ND) was higher (p < 0.05) in GSP + OZ groups compared to control treatment. The value of malondialdehyde (MDA) decreased (p < 0.05) under GSP + OZ diets compared to control. Moreover, paraoxonase (PON1) was higher (p < 0.05) in GSP + OZ groups compared to untreated broilers. In conclusion, GSP + OZ positively supported growth traits, reduced MDA, and augmented PON1 and HI titer against ND in broilers exposed to heat stress.


2019 ◽  
Vol 32 ◽  
pp. 282-290
Author(s):  
Nada A. El-Qatrani

This study was carried out in the nursery of Department of Horticulture and Landscape Design, College of Agriculture, University of Basrah during 2018 growing season. Completely randomized blocks design (C.R.B.D.)  was used to investigate the effect of different concentrations of super swing (0, 0.5 and 1) g.l-1 and whey (0, 50 and 75) % and their interactions to enhance the growth parameters and chemical characteristics of Sour orange transplants. The results showed a significant increase in most of the measured growth parameters of transplants treated with high concentration of foliar spraying to both fertilizers. Application of super swing at 1 g.l-1 with whey at 75% together significantly increased the height of plant, the number of leaves, leaf area, the diameter of stem, number of flowers, the leaves content of both nitrogen and potassium, percentage of dry matter, and content of chlorophyll. Whereas, control treatment was significantly increased the water content compared to other treatments. Addition of growth-enhancing compounds such as super swing and whey extract to the plant can improve the metabolic performance and enhances the plant's ability to absorb nutrients from the soil.


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