Jerusalem Artichoke Varieties Research Articles

Diversity of bacterial community in Jerusalem artichoke (Helianthus tuberosus L.) during storage is associated with the genotype and carbohydrates.

Jerusalem artichoke (JA) is a fructan-accumulating crop that has gained popularity in recent years. The objective of the present study was to determine the dynamics of the JA-microbiome during storage. The microbial population on the surface of the JA tuber was determined by next-generation sequencing of 16S rRNA amplicons. Subsequently, the changes in carbohydrate and degree of polymerization of fructan in tubers during storage were measured. Among different genotypes of JA varieties, intergeneric differences were observed in the diversity and abundance of bacterial communities distributed on the surface of tubers. Additionally, bacterial diversity was significantly higher in storage-tolerant varieties relative to the storage-intolerant varieties. Redundancy analysis (RDA) and the correlation matrix indicated a relationship between changes in the carbohydrates and microbial community succession during tuber storage. The tuber decay rate correlated positively with the degree of polymerization of fructan. Moreover, Dysgonomonas and Acinetobacter in perishable varieties correlated significantly with the decay rate. Therefore, the bacteria associated with the decay rate may be involved in the degradation of the degree of polymerization of fructan. Furthermore, Serratia showed a significant positive correlation with inulin during storage but a negative correlation with the decay rate, suggesting its antagonistic role against pathogenic bacteria on the surface of JA tubers. However, the above correlation was not observed in the storage-tolerant varieties. Functional annotation analysis revealed that storage-tolerant JA varieties maintain tuber quality through enrichment of biocontrol bacteria, including Flavobacterium, Sphingobacterium, and Staphylococcus to resist pathogens. These results suggested that crop genotype and the structural composition of carbohydrates may result in differential selective enrichment effects of microbial communities on the surface of JA varieties. In this study, the relationship between microbial community succession and changes in tuber carbohydrates during JA storage was revealed for the first time through the combination of high-throughput sequencing, high-performance liquid chromatography (HPLC), and high-performance ion-exchange chromatography (HPIC). Overall, the findings of this study are expected to provide new insights into the dynamics of microbial-crop interactions during storage.

Jerusalem Artichoke as a Strategic Crop for Solving Food Problems

Jerusalem artichoke is a staple for the raw material base of healthy food, beverages, feed, medicine, and fuel, in addition to being the source of its herbage and tubers. The choice of conditions for cultivating a variety depends on the purpose or direction for the crop and the products obtained from it. This research involved laboratory and on-farm studies of 16 Jerusalem artichoke varieties of different maturity groups cultivated on sod-podzolic sandy loam soils to determine their suitability for further use in feed production. The list of varieties in question is presented in this work. The gross yield of tubers obtained from varieties with early leaf wilting was 33.1–51.1 t/ha, whereas that from varieties with late leaf wilting was 14.4–43.9 t/ha. The total yield of Jerusalem artichoke raw biomass was 36.8–98.1 t/ha. Moreover, early varieties had a dominant mass of tubers in the total feed value structure (68%), whereas herbage mass (59%) prevailed in the total feed value structure of varieties with late leaf wilting. The highest total solids in tubers (25.0–26.4%) were found in varieties Korenevskiy, Novost VIRa, and Blank Brekos; whereas high inulin content was found in varieties Dieticheskiy, Kaluzhskiy, Korenevskiy, Nakhodka, Novost VIRa, and Blank Brekos. The aggregate feed value amounted to 37.0–103.4 thousand MJ/ha of metabolized energy; this exceeded energy production costs on properly selected varieties by two- to three-fold. The data obtained can be useful for growers in the introduction and evaluation of Jerusalem artichoke varieties to be cultivated for further usage and processing, including fodder purposes.

INVESTIGATION OF PHYSICO-CHEMICAL PROPERTIES OF TOPINAMBUR (THE JERUSALEM ARTICHOKE) WITH THE PURPOSE OF ITS PROCESSING INTO ALCOHOL AND FUNCTIONAL FOOD PRODUCTS

The analysis of the physicochemical composition and nutritional value of Jerusalem artichoke varieties cultivated in Russia has been carried out. Experimental data have been obtained on its processing into alcohol and functional products based on dietary fiber enriched with protein, amino acids, vitamins, and inulin.

Inulin content of Jerusalem artichoke (Helianthus tuberosus L.) tubers stored at 5 oC in a refrigerator for different durations

Jerusalem artichoke is a perennial crop, but it is grown as an annual crop for its inulin containing tubers. Various factors affect inulin content, in which storage duration is one of the significant causes. Therefore, the effect of different storage durations on inulin content of Jerusalem artichoke was investigated in this study. Four Jerusalem artichoke varieties were assigned as factor A, and six durations of storage at 5 oC were assigned as factor B. The 24 treatment combinations of a 4×6 factorial were arranged in a completely randomized design with four replications. After harvest, the tubers were cleaned and stored at 5 oC for five months. Inulin content was analyzed consecutively at 0, 1, 2, 3, 4 and 5 months after storage. Times of storage and varieties were significantly different (P<0.01) for inulin content. Stored tubers had inulin contents ranging from 35.9 to 43.7 % compared to 47.8 % of freshly-harvested tubers. The lowest inulin content was found after 2 months of storage. JA 89 had the highest inulin content (47.80%), whereas CN52867 had the lowest inulin content (35.85%). Regression analysis showed small and insignificant effect of storage time on inulin content, and the results are discussed. The results will be useful for consumers and industries for their concern on storage loss of inulin content after storage

Transcriptome profiling of Jerusalem artichoke seedlings (Helianthus tuberosus L.) under polyethylene glycol-simulated drought stress

Drought stress is one of the most important abiotic stresses affecting crop growth and development, which leads to huge production and economics losses. Jerusalem artichoke (Helianthus tuberosus L.) is a perennial crop with high drought tolerance that can be used in ecological management. In this study, Jerusalem artichoke seedlings under polyethylene glycol (PEG) 6000-simulated drought stress were used for analysis of malonaldehyde, proline, and soluble sugar content, then the differentially expressed unigenes were identified by RNA-sequencing. A total number of 172,291 unigenes were generated from the leaves of Jerusalem artichoke and 17,612 unigenes were identified as differentially expressed unigenes. Gene Ontology enrichment showed that differential expression genes were classified in plastoglobules, photosystem II, and photosystem. Kyoto Encyclopedia of Genes and Genomes enrichment showed that differential expression genes were mainly classified in metabolic pathways; biosynthesis of secondary metabolites; photosynthesis - antenna proteins; circadian rhythm-plant; porphyrin and chlorophyll metabolism; phenylpropanoid biosynthesis; ABC transporters; flavonoid biosynthesis; carotenoid biosynthesis; stilbenoid, diarylheptanoid, and gingerol biosynthesis; cutin, suberin, and wax biosynthesis; and isoquinoline alkaloid biosynthesis. A transcription factor analysis showed that NAC, MYB, WRKY, homeobox-leucine zipper (HD-ZIP) and basic leucine-zipper (bZIP) were considered to be closely related to the response to PEG-simulated drought stress. These findings suggest that transcription factors may respond to drought stress by regulating structural genes expression level in metabolic pathways and then regulating the accumulation of related metabolites. Results obtained in this study will be helpful for cloning and analysis of drought-resistant genes of Jerusalem artichoke in the future, and also lay the foundation for the explanation of the drought resistance mechanism of Jerusalem artichoke and are helpful for the identification of drought tolerant Jerusalem artichoke varieties.

Research results of Jerusalem artichoke varieties and hybrids in the forest-steppe of the Omsk region

The article presents the five-year results of the studying the adaptation of varieties, and hybrids of Jerusalem artichoke in the forest-steppe of the Omsk region. The analysis of biometric indicators and crop yield structure is presented. The dynamics of the accumulation of herbage, as well as the periods of the passage of phenological phases are shown. The chemical composition of plants is determined. The studies show that many hybrids and varieties in Western Siberia do not go through the flowering phase, but at the same time form a full-fledged tuber crop. At the same time, the high yield of the aerial mass of Jerusalem artichoke does not always ensure a high yield of tubers. On average, for five years of research, the French D-5 hybrid, Canadian sample and variety samples’ No. 1 and No. 9 we distinguished in terms of herbage productivity. This indicator was 49.4-58.9 t / ha. In terms of tuber productivity, the best varieties were No. 9 and No. 12, as well as the Sireniki-1 variety (29.1-30.2 t / ha). The distinguished varieties and hybrids of Jerusalem artichoke are recommended for the introduction into production in order to improve the forage base of agricultural enterprises. The research on the selection of varieties and hybrids in order to obtain high-tech tubers (large and aligned) for processing in the food industry will be continued.

Genetic diversity of phenotypic traits in 257 Jerusalem artichoke accessions

Abstract: In order to fully understand and effectively utilize the genetic diversity of Jerusalem artichoke accessions in China. 257 Jerusalem artichoke accessions were analyzed. Among them, 12 quantitative traits had 6%–50% of the coefficient of variation, with a mean of 24.75%, which was the highest in tuber weight per plant (50%) and the smallest in growth period (6%). The diversity index ( H′ ) of these 12 traits was 1.24–1.53, with a mean of 1.44, which was the highest in tuber number per plant (1.53) and the lowest in leaf width (1.24). The diversity index of the eight quality traits was 0.85–1.08, with a mean of 0.98, which was the highest in tuber habit and the lowest in tuber uniformity, showing rich genetic diversity in most traits. The subordinate function of 257 Jerusalem artichoke accessions was 0.12–0.58, in which the highest was in JA1095 (0.58) with the obvious advantages of flower number and tuber weight per plant. The correlation analysis of 12 quantitative traits indicated that stem diameter, leaf length, flower and disk size could be used as the main target traits for high yield Jerusalem artichoke varieties breeding in the future. The results of principal component analysis showed that the cumulative contribution rate of the seven principal component factors was 66.794%. Among them, the number of flowers, the tuber number per plant, the number of tuber hairs and the smoothness of tuber epidermis were the main factors contributing to the phenotypic difference of Jerusalem artichoke. By cluster analysis, 257 accessions materials were divided into five categories based on 20 traits,among them class I and class II accounted for 85% of the total germplasm resources. This results can provide an important reference for the utilization of Jerusalem artichoke accessions and variety breeding.

Effective Plant Ages for Screening for Field Resistance to Alternaria Leaf Spot (Caused by Alternaria spp.) under Natural Infection in Jerusalem artichoke (Helianthus tuberosus L.)

Host plant resistance has proven to be effective for controlling Alternaria leaf spot on Jerusalem artichoke (JA), but efficient screening techniques have not been developed yet. The objective of this study is to estimate the relationship between disease resistance parameters of JA as a function of plant age. Six JA varieties and three plant ages at the time of inoculation (20, 40 and 60 days after transplanting) (DAT) are evaluated in a factorial experiment in randomized complete block design (RCBD) with four replications. Disease incidence (DI) and severity (DS) are estimated, from which area under the disease progress curve (AUDPC) was calculated. Disease parameters are positively and significantly correlated for plant ages of 40 and 60 DAT. Based on our results, screening of JA at 40 DAT for resistance to Alternaria leaf spot is recommended. Knowledge of the impact of plant age on resistance to key diseases can help breeders to accelerate breeding programs so superior genotypes can be identified before reproductive growth stages.

Biological Control of Alternaria Leaf Spot Caused by Alternaria spp. in Jerusalem Artichoke (Helianthus tuberosus L.) under Two Fertilization Regimes.

The objectives of this study were to evaluate the efficacy of integrating resistant genotypes of Jerusalem artichoke with Trichoderma harzianum isolate T9 to control Alternaria leaf spot caused by Alternaria spp. under two fertilization regimes and to determine whether T9 application induced chitinase and β-1,3-glucanase activity in Jerusalem artichoke leaves. Six Jerusalem artichoke varieties (resistant varieties JA15, JA86, and JA116 and susceptible varieties HEL246, HEL293, and JA109) and three disease control methods (a non-inoculated control, application of T. harzianum T9, and fungicide sprays (propiconazole at a rate of 30 mL/20 L of water, 375 ppm)) was conducted in two separate trials (different fertilization regimes) at the experimental farm of the Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand. Resistant genotypes controlled Alternaria leaf spot effectively. Application of Trichoderma showed low efficacy to control Alternaria leaf spot, but in specific susceptible genotypes—HEL246 and HEL293—the application of Trichoderma could reduce disease severity up to 10%. The application of Trichoderma was associated with a rise in production of chitinase and β-1,3-glucanase in HEL246 seedlings. The number of Trichoderma propagules in soil, as well as the extent of colonization of roots and leaves, were monitored. The results indicated that application of Trichoderma had higher propagules than non-inoculated control. Neither varietal resistance nor the disease control methods used in this study impacted the yield or yield components of Jerusalem artichoke.

FEATURES OF FORMATION OF PRODUCTIVITY OF DIFFERENT VARIETIES OF TOPINAMBUR

The article presents the results of studies of the characteristics of growth and development, the formation of the productivity of topinambur varieties. The value of the assimilation surface of plants, the productivity of photosynthesis of various genotypes of Jerusalem artichoke was determined. On one plant of Jerusalem artichoke varieties White yield formed the largest number of leaves - 52.4 pcs., Which is 11.8% more than control. Due to the large size and number of leaves, this variety of Jerusalem artichoke provided the maximum leaf area of a single plant - 114 cm2, as well as the leaf area from the reference areas - 63.5 thousand m-2 / ha. Indicators of the net productivity of photosynthesis of Jerusalem artichoke varieties were in the range of 8.3-14.2 g/m2 per day. The varieties of this crop, White Kiev and White, are high yields compared with the control, had higher photosynthesis productivity indices by 4.8-8.3%. The mass of tubers of a single plant of the Jerusalem artichoke varieties was in the range of 304-407 g. It should be noted that White Kiev and White harvest formed large tubers of mass by 8.4-12.7% compared with the control. Research results indicate that, on average, over the years of research (2016-2017), Jerusalem artichoke varieties had a different effect on tuber yield. Thus, the highest yield of tubers (28.5 tones per hectare) was provided by the middle ripening variety White, which is 7.3 tones per hectare more than the early varieties of Vadim (control). In the middle of the day.

Variability of Alternaria Leaf Spot Resistance in Jerusalem Artichoke (Helianthus tuberosus L.) Accessions Grown in a Humid Tropical Region

Alternaria leaf spot is an emerging disease of Jerusalem artichoke (Helianthus tuberosus L.) in tropical regions. The lack of known resistant germplasm sources is an important constraint to development of Jerusalem artichoke varieties with resistance to Alternaria leaf spot. The objectives of this study were to identify variability of Jerusalem artichoke genotypes for resistance to Alternaria leaf spot under field conditions and to investigate the relationships among resistance characters, yield, and yield components for selection of resistant varieties. Ninety six accessions of Jerusalem artichoke were evaluated in replicated trials under field conditions in early rainy and late rainy seasons in Khon Kaen, Thailand during 2014. Parameters evaluated included disease incidence, disease score, disease severity index, area under disease progress curve of disease incidence, area under disease progress curve of disease severity index, number of tubers/plants, tuber size, and fresh tuber yield. The genotypes HEL 335, HEL 256, HEL 317, HEL 308, and JA 86 were identified as sources of leaf spot resistance in both seasons. These genotypes can be used as sources of leaf spot resistance for Jerusalem artichoke breeding programs. HEL 293 and HEL 246 showed susceptibility to leaf spot disease in both seasons and should be used as standard susceptible checks.

Valorification of Jerusalem Artichoke Tubers (Helianthus Tuberosus) for Achieving of Functional Ingredient with High Nutritional Value

Abstract Jerusalem artichoke tubers (Helianthus tuberosus) are distinguished by their protein, minerals (potassium, calcium, magnesium, iron, etc.) and inulin content. Inulin can be used in the diet of diabetics as a substitute of sugar, without having an impact on blood glucose. At the same time, an international study had shown that due to their inulin content, regular consumption of Jerusalem artichoke tubers can help to prevent type 2 diabetes. In this paper are presented the results of the researches performed to achieve a functional ingredient (powder) with high nutritional value by processing of Jerusalem artichoke tubers. Thus, the Jerusalem artichoke tubers (Red Jerusalem artichoke and White Jerusalem artichoke varieties) were subjected to a convective drying process at 50°C, to protect bioactive components (vitamins, phenolic compounds, etc.) to a moisture content that allow their milling and turning them into powder and, at the same time, their stability in terms of quality. The achieved functional ingredient was evaluated sensory, physicchemically and microbiologically. The powder obtained from Jerusalem artichoke tubers is characterized by their inulin-type fructans (51.60... 57.45%), crude fiber (6.85...8.27%), total polyphenols (18.51... 44.03 mg GAE/g), proteins (8.75...9.26%), iron (12.45...13.88 mg/100g), potassium (1905.44...2100.35 mg/100g), calcium (50.21...57.45mg/100g), magnesium (84.55...89.95mg/100g) and phosphorus content (300.12...345.35 mg/100g). At the same time, powder achieved from Jerusalem artichoke tubers has antioxidant potential. Due to its complex biochemical composition, the functional ingredient achieved from Jerusalem artichoke tubers can be used to fortify food and also as a sweetening agent for products destined to diabetics.

Jerusalem artichoke (Helianthus tuberosus L.) as a potential chlorophyll source for humans and animals nutrition

The current research was aimed to evaluate the vegetative part of seven ecotypes/varieties of Jerusalem artichoke as a potential source for chlorophyll. Alfalfa (Hunor variety) was applied as a control. Open field experiment was carried out during spring season 2016 at Horticultural Demonstration Garden at the University of Debrecen, Hungary. Pigments were measured in intact leaves, green juice and fiber fraction of different Jerusalem artichoke ecotypes/varieties. Results verified that alfalfa had higher contents of different photosynthetic pigments in both intact leaves and green juice, while fiber fraction of Jerusalem artichoke ecotypes/varieties contained higher photosynthetic pigments contents. Among Jerusalem artichoke varieties, Piri ecotype had highest chlorophyll a (6.199 mg g-1 DM), carotenoids (8.865 mg g-1 DM) and xanthophyll (2.946 mg g-1 DM) contents in fiber fraction than other varieties. In green juice fraction, highest contents of carotenoids and xanthophyll (1.752 and 0.709 mg g-1 DM, respectively) were corresponded to Rubic ecotype. Intact leaves of Tapioi sima ecotype had the highest contents of chlorophyll a and xanthophyll (8.478 and 2.977 mg g-1 DM, respectively) compared to other varieties. While Alba plants had the highest chlorophyll b content in both leaves and fiber fraction (2.307 and 3.184 mg g-1 DM, respectively), Fuza ecotype recorded the highest content of chlorophyll b and carotenoids (1.042 and 4.042 mg g-1 DM, respectively) in green juice and leaves, respectively. However, these results revealed that green leaves of Jerusalem artichoke as it is or fractionated as green juice and fiber fractions are potential sources for chlorophyll .

CARBOHYDRATES CONTENT IN JERUSALEM ARTICHOKE TUBERS DURING VEGETATION

Jerusalem artichoke (Helianthus tuberosus L.) is rich in vitamins, carbohydrates, fiber. Tubers of Jerusalem artichoke consist valuable substance inulin, which has a complex of health properties. Breeders create new hybrids and varieties of Jerusalem artichoke to increase the content of nutrients, productivity and climate resilience. The authors analysed moisture content, dry residue and fractional composition of carbohydrates in the tubers of Jerusalem artichoke varieties Skorospelka and Sireniki and the hybrids PBB and PBK in various phases of vegetation. In the flowering stage the moisture of the tubers of the investigated varieties was in the range of 77.2-81.3 percent, the value of dry residue of nutrients was 18.7-22.8 percent. The greatest number of non-reducing and total sugars in the flowering stage contained in the tuber varieties of Sireniki and was equaled 78.3 and 61.8 percent, respectively. A similar analysis was conducted in the maturation phase. In this phase the solids content slightly increased and amounted to 22.9-26.2 percent. Non- reducing sugars content, including inulin, increased in all the studied samples of Jerusalem artichoke. However, the greatest values of 72 percent were noted for variety Sireniki and hybrid PBK. The content of inulin depends on the phase of the growing season and the varietal characteristics of Jerusalem artichoke and the absence of decisive superiority of the hybrids.

Inoculation with Sclerotium rolfsii, cause of stem rot in Jerusalem artichoke, under field conditions

Stem rot caused by Sclerotium rolfsii is an important problem of Jerusalem artichoke, and breeding of Jerusalem artichoke for resistance to stem rot requires effective screening methods. The objective of this study was to compare methods for inoculating Jerusalem artichoke with S. rolfsii under field conditions. A 4 × 2 × 3 factorial in a randomized complete block with four replications was used in two environments characterized by different rates of fertilizer application (recommended rate and low rate) in the rainy season. The factors included four Jerusalem artichoke varieties (HEL280, HEL278, HEL256 and JA49), two levels of wounding (wounded and not wounded) and three methods of inoculation. The inoculation methods consisted of: 1) non-inoculated natural infection; 2) attaching one colonized sorghum seed at the crown of plants (single sorghum seed method); and 3) spreading 30 g m−2 of colonized sorghum seeds (broadcast inoculation method). Jerusalem artichoke varieties and inoculation methods were significantly different for disease incidence, whereas the difference between wounded and non wounded treatments was not significant. Significant interactions were found between the variety and wounding method, the variety and inoculation method, wounding method and inoculation method, and inoculation method and environments. Natural infection resulted in the lowest disease incidence (32.2 %), whereas the single sorghum seed and the broadcast inoculation methods had a high disease incidence (79.0 % and 77.3 % respectively) and were not signnificantly different from each other. Broadcast inoculation did not allow differentiation of Jerusalem artichoke varieties for disease incidence, whereas single seed inoculation could better identify the differences among Jerusalem artichoke varieties.

Effects of water stress on total biomass, tuber yield, harvest index and water use efficiency in Jerusalem artichoke

The objectives of this study were to determine the effects of drought on tuber yield, total biomass, harvest index, water use efficiency of tuber yield (WUEt) and water use efficiency of biomass (WUEb), and to evaluate the differential responses of Jerusalem artichoke (JA) varieties under drought stress. The 3×5 factorial combinations of three water regimes (Field capacity (FC), 50% available soil water (50%AW) and 25%AW), and five JA varieties (JA 60, JA 125, JA 5, JA 89 and HEL 65) were arranged in a pot experiment in a randomized complete block design with four replications for two years. Data were recorded for tuber dry weight, total biomass, harvest index, WUEt and WUEb at harvest. Drought reduced tuber dry weight, total biomass, harvest index, WUEt and WUEb, and reductions were more severe under the severe drought stress of 25%AW. Varieties were significantly different for all traits under drought and well-watered conditions. The JA varieties were classified into three groups. The first category was comprised of the JA 5 variety with high tuber yield potential and low drought tolerance, the second category consisted of JA 60 and JA 125 varieties with low tuber yield potential and high drought tolerance, and the third group included JA 89 and HEL 65 varieties with low tuber yield potential and low drought tolerance. The multiple regression analysis showed that tuber yield, total biomass and harvest index at 50%AW and 25%AW depended largely on the reductions of tuber yield, total biomass and harvest index under drought. Therefore, the results of this study recommend that the selection of JA genotypes with low reduction in yield under drought stress could be a criterion in drought resistance breeding programs for development of JA varieties with high tuber yield under drought stress. JA with drought tolerance in this study means high tuber yield under drought conditions. JA 5 had high yield and WUEt across water regimes and could be used as parental source for drought tolerance breeding programs in further research.

Root responses of Jerusalem artichoke genotypes to different water regimes

The objective of this study was to determine effects of drought on selected root growth parameters and develop relationships between root parameters and tuber yield for selected Jerusalem artichoke (JA) genotypes. Three water regimes (Field capacity, 50% available soil water (AW) and 25% AW) and five JA varieties (JA 60, JA 125, JA 5, JA 89 and HEL 65) were planted with factorial treatments in a randomized complete block design with four replications. Data on root dry weight (RDW) and root: shoot ratios (RSR) were measured manually. Root diameter (RD), root length (RL), root surface area (RSA) and root volume (RV) were collected at harvest. Drought tolerance indices (DTI) were calculated for all root parameters. Drought reduced all root parameters and DTI but increased RSR in JA 60, JA 125, JA 5, and HEL 65. JA 125 had high values for all root traits and DTI of these traits under drought stress. JA 60 had high DTI of RDW, RD and RSR under mild and severe water stress. JA 5 had high DTI of RDW, RD, RL, RSR and RV under drought conditions. JA 89 and HEL 65 performed well for RDW, RD, RL and low DTI of all root characteristics. DTI for root parameters were positively correlated with tuber dry weight under mild and severe water stress. The JA 5, JA 60 and JA 125 varieties showed high DTI for some root traits, indicating that better root parameters contributed to higher tuber yield under drought stress.

Biomass Accumulation and Nutrient Uptake of Jerusalem Artichoke (<i>Helianthus tuberosus</i> L.)

The dynamics of biomass accumulation during the growing period, the yield of leafy stalks and tubers, and the nutrient concentration and nutrient uptake of the yield were investigated for two Jerusalem artichoke varieties (Tápiói Korai and Tápiói Sima) in a field experiment involving mineral fertilisation. Considerable differences were observed between the dynamics of leafy stalk and tuber development in Tápiói Korai which has a short vegetation period and Tápiói Sima where the vegetation period is long. The maximum dry matter ratio between the tuber yield and the leafy stalk yield was 1:1 for Tápiói Korai and 1:4.5 for Tápiói Sima. During the period when the maximum aboveground biomass developed in Tápiói Korai, 100 kg.ha-1 N and P fertiliser resulted in the highest leafy stalk yield (38.34 t.ha-1), while for Tápiói Sima, which developed a much greater leafy stalk mass, the highest aboveground biomass yield (78-80 t.ha-1) was given in response to 200 kg.ha-1 N supplemented by P and K fertiliser. Both artichoke varieties produced the great-est tuber yield at a N rate of 200 kg.ha-1, supplemented with P and K fertiliser. The nutrient concentration in the leafy stalks was highest on the 85th day of the vegetation period, prior to intensive dry matter accumulation in the leafy stalks and before tuber formation began. In both varieties the maximum nutrient uptake was recorded on the 155th day. Great differences were observed between the varieties in terms of specific nutrient uptake. For a tuber yield of 10 t, together with the corresponding leafy stalk yield, the specific nutrient uptake of the Tápiói Korai variety amounted to 48 kg N, 10 kg P, 83 kg K, 30 kg Ca and 10 kg Mg, while for Tápiói Sima these figures were 162 kg N, 30 kg P, 300 kg K, 84 kg Ca and 45 kg Mg.

Growth, photosynthesis and H+-ATPase activity in two Jerusalem artichoke varieties under NaCl-induced stress

In order to evaluate differential growth, photosynthesis and H+-ATPase activity responses to salt-induced stress, two Jerusalem artichoke (Helianthus tuberosus L.) genotypes (Nanyu No. 1 and Qingyu No. 2) were used in sand-culture experiment with different concentrations of NaCl (0, 30, 60, 90, 120 and 150mM). After 20 days of growth, the NaCl stress resulted in a decrease of biomass accumulation, relative leaf expansion rate and photosynthetic rate, but an increase of proline content in both genotypes. Compared with Qingyu No. 2, Nanyu No. 1 had lower biomass, photosynthetic rate, gas exchange and transpiration rate, but higher proline content, activities of plasma membrane H+-ATPase (PM H+-ATPase) and vacuolar membrane H+-ATPase (VM H+-ATPase). Hence, the NaCl adaptation strategy in Nanyu No. 1 was by lowering photosynthetic rate, stomatal conductance and transpiration rate while maintaining high H+-ATPase activities, whereas the adjustment of Qingyu No. 2 was by keeping much higher rate of proline accumulation and concentration of chlorophyll. The differences in salt tolerance showed that different adaptation mechanisms existed between cultivars of Jerusalem artichoke. The findings offered the possibility of selecting salt-tolerant genotypes of Jerusalem artichoke.

Antioxidant enzymes and physiological characteristics in two Jerusalem artichoke cultivars under salt stress

The effects of NaCl stress on the activity of antioxidant enzymes, lipid peroxidation, cell membrane stability, net photosynthetic rate, gas-exchange, and chlorophyll content were investigated in two Jerusalem artichoke cultivars, Dafeng (salt-tolerant) and Wuxi (salt-sensitive), grown under control (nutrient solution) or salt stress (nutrient solution containing 75, 150, and 225 mM NaCl) conditions for 7 days. In leaves of salt-tolerant cv. Dafeng, superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), and catalase (EC 1.11.1.6) activities significantly increased as compared to the controls, whereas no significant change was observed in cv. Wuxi. Lipid peroxidation and cell membrane injury were enhanced in both cultivars. Net photosynthesis and stomatal conductance decreased in response to salt stress, but cv. Dafeng showed a smaller reduction in photosynthesis than cv. Wuxi. The results indicated that stomatal aperture limited leaf photosynthetic capacity in the NaCl-treated plants of both cultivars. However, significant reduction in the leaf chlorophyll content due to NaCl stress was observed only in cv. Wuxi. These results suggested that salt-tolerant Jerusalem artichoke varieties may have a better protection against reactive oxygen species, at least in part, by increasing the activity of antioxidant enzymes under salt stress.