Bicarbonate-induced Chlorosis Research Articles

Evaluation of eleven kiwifruit genotypes for bicarbonate tolerance and characterization of two tolerance-contrasting genotypes

Screening bicarbonate-tolerant genotypes is an environmentally-friendly and long-term effective strategy to cope with bicarbonate-induced chlorosis in fruit crops grown on calcareous soils. We investigated eleven genotypes from four kiwifruit species (Actinidia chinensis, A. macrosperma, A. polygama, and A. valvata) for differences in bicarbonate tolerance. We also characterized the physiological and molecular differences in two contrasting genotypes of this group. In the first experiment, bicarbonate-treated plantlets were irrigated with 3.0 g L−1 CaCO3 and 5.04 g L−1 NaHCO3 in peat and perlite medium culture. Based on principal component analysis, weight-based membership function method and cluster analysis, the tested genotypes were classified into three groups: (1) tolerant, including YX, Av-1, Acd, Ap, Av-2, and QM; (2) moderately tolerant, including Av-3, Am, Av-4, and HWD; and (3) sensitive, including only QH. In the second experiment, QH (bicarbonate-sensitive) and YX (bicarbonate-tolerant) were grown in sand culture with 4.0 g L−1 CaCO3 and 0.84 g L−1 or 1.26 g L−1 NaHCO3. Compared with QH, YX showed a better ability to take up iron (Fe) by roots and to transport Fe from roots to shoots in the bicarbonate treatments, probably due to a better capacity to protect from oxidative damage and to excrete protons, and a differential expression of genes associated with Fe uptake and translocation, including HA8, IRT1, YSL3 and NRAMP3. The results can facilitate identifying potential resources for bicarbonate tolerance and breeding new rootstocks, and contribute to the elucidation of the bicarbonate tolerance mechanisms in the genus Actinidia.

Anatomical and physiological responses of two kiwifruit cultivars to bicarbonate

Bicarbonate-induced chlorosis is a common agricultural problem that affects both the quantity and quality of fruit crops grown on calcareous soils. However, little is known about the responses of kiwifruit to bicarbonate stress. In the present study, we investigated the anatomical and physiological responses of two kiwifruit cultivars (‘Nongdajinmi’ and ‘Xuxiang’) grafted onto the same rootstock (‘Qinmei’) to bicarbonate (0.50 g/L CaCO3 and 0.84 g/L NaHCO3) under sand culture. After 35 days, bicarbonate-treated vines exhibited yellowing symptoms and decreased chlorophyll content in new expanded leaves. Bicarbonate imposition decreased N and Cu concentration in new leaves and P in old leaves. Moreover, bicarbonate decreased the dry weight of the new leaves and twigs and degenerated the chloroplast, particularly in ‘Nongdajinmi’, suggesting that ‘Nongdajinmi’ is more sensitive to bicarbonate than ‘Xuxiang’.However, bicarbonate treatment thickened palisade tissue and decreased the phenolic content in ‘Nongdajinmi’ and lowered the organic acid content and stomatal length, width and aperture size in ‘Xuxiang’. Interestingly, bicarbonate raised Ca concentration in new leaves and reduced Mg in old leaves of ‘Nongdajinmi’, but the opposite was true for ‘Xuxiang’. These results implied that the two cultivars adopted two different mechanisms in response to bicarbonate stress. Our study contributes to better understanding the responsive mechanisms of kiwifruit to bicarbonate and the cultivar selections for kiwifruit orchards established on calcareous soils.

Nitric oxide content is associated with tolerance to bicarbonate-induced chlorosis in micropropagated Prunus explants

Iron (Fe) chlorosis is a common nutritional deficiency in fruit trees grown in calcareous soils. Grafting on tolerant rootstocks is the most efficient practice to cope with it. In the present work, three Prunus hybrid genotypes, commonly used as peach rootstocks, and one peach cultivar were cultivated with bicarbonate in the growth medium. Parameters describing oxidative stress and the metabolism of reactive nitrogen species were studied. Lower contents of nitric oxide and a decreased nitrosoglutathione reductase activity were found in the most sensitive genotypes, characterized by higher oxidative stress and reduced antioxidant defense. In the peach cultivar, which behaved as a tolerant genotype, a specifically nitrated polypeptide was found.

Use of in vitro method to evaluate some grapevine varieties for tolerance and susceptibility to sodium bicarbonate-induced chlorosis

ABSTRACT Nodal shoot segments of four grapevine genotypes well known for their Fe-chlorosis characteristic [Vitis vinifera × Vitis berlandieri Fercal, resistant; V. berlandieri × Vitis rupestris 1103 P, mid-resistant; Solonis (Vitis riparia × V. rupestris × Vitis candicans) × Othello (Vitis labrusca × V. riparia × V. vinifera) 1613 C, susceptible; V. vinifera L. cv. Perlette, resistant] were cultured in vitro. The effects of three levels of iron sodium ethylene-diaminotetraacetate (FeNaEDTA; 9, 18, 36 mg l−1) and three mixtures of iron and 840 mg l−1 NaHCO3 (sodium bicarbonate) in the Murashige and Skoog (MS) medium supplemented 4.9 μM indole-3-butyric acid (IBA) were compared. We assayed the chlorosis rating of leaves, total chlorophyll of leaves, dry shoot weights of the plantlets, and active and total Fe content of the leaves. The most suitable concentration in determining the reaction of genotypes to iron chlorosis was 9 mg l−1 FeNaEDTA. Bicarbonate addition had negative effects on the iron intake and...

DIFFERENT RESPONSES INDUCED BY BICARBONATE AND IRON DEFICIENCY ON MICROSHOOTS OF QUINCE AND PEAR

The effects of bicarbonate-induced chlorosis and iron deficiency were investigated using shoots of quince clone 'MA' and pear cultivar Conference in in vitro culture. The ability of 'Conference' to reduce the pH value of media was higher than that of clone 'MA' at day 12; the difference of H+ extrusion between the two genotypes was less evident under all treatments, although 'Conference' maintained a higher degree of acidification at day 24. Bicarbonate and iron deficiency decreased total chlorophyll content in clone 'MA', with a probable interaction, while in 'Conference' a strong decrement of chlorophyll content was only detected under iron absence. Fresh weight increment was affected only in clone 'MA' by Fe-limiting conditions. Apical dominance was increased by all stress conditions in clone 'MA', while in 'Conference' a significative increment in apical dominance was observed only under Fe deficiency and bicarbonate treatment. All the data show that in vitro techniques can help to unravel physiological mechanisms that undergo the strategies of plant adaptation to calcareous soils: the most common markers used for iron chlorosis are differently affected by iron availability and potassium bicarbonate in both species.

Influence of Sodium Bicarbonate on the Growth and Chlorosis of Garden Beets

1. The response of beet plants to additions of 0, 8, 16, and 32 meq/l NaHCO3 to a base nutrient solution was compared with the response of bean plants grown on substrates of the same composition in a previous experiment. 2. The growth of beets was less influenced by the level of the bicarbonate ion in the substrate than was the growth of beans. 3. The bicarbonate treatments effected large accumulations of sodium and oxalate in beet leaves. 4. Comparison of cation accumulation in bean and beet leaves showed that treatment and chlorosis were not correlated with any particular cation or with the K/Ca ratio in both species but rather with monovalent cations or the Na + K/Ca + Mg ratio. 5. The increased accumulation of organic acids in bicarbonate-induced chlorosis appears to depend on the maintenance of ionic balance.

The Chemical Status of Bean Plants Afflicted with Bicarbonate-Induced Chlorosis

1. The response of bean plants to additions of 8, 16, and 32 m.e./l. NaHCO3 to a base nutrient solution was compared with that of plants grown on base nutrient solution adjusted to pH 8.0 with NaOH. 2. Higher concentrations of sodium bicarbonate were associated with greater intensities of chlorosis and marked inhibition in growth. 3. The treatments primarily effected a lowered iron "activity" and calcium content of the leaves and an enhanced potassium content. 4. The accumulation of citric acid in leaves showing intensified chlorosis was found to be a direct concomitant of potassium content. 5. It is suggested that the primary effect of the bicarbonate ion was through its effect on protoplasmic consistency of the absorbing cells of the roots so that these bean plants showed an accentuated accumulation of monovalent cations and a depressed accumulation of divalent cations. 6. The relation of bicarbonate-induced chlorosis to lime-induced chlorosis in the field is discussed.