Su-Yeon Lee

Metabolomic profiling from leaves and roots of tomato (Solanum lycopersicum L.) plants grown under nitrogen, phosphorus or potassium-deficient condition.

Specific metabolic network responses to mineral deficiencies are not well-defined. Here, we conducted a detailed broad-scale identification of metabolic responses of tomato leaves and roots to N, P or K deficiency. Tomato plants were grown hydroponically under optimal (5mM N, 0.5mM P, or 5mM K) and deficient (0.5mM N, 0.05mM P, or 0.5mM K) conditions and metabolites were measured by LC-MS and GC-MS. Based on these results, deficiency of any of these three minerals affected energy production and amino acid metabolism. N deficiency generally led to decreased amino acids and organic acids, and increased soluble sugars. P deficiency resulted in increased amino acids and organic acids in roots, and decreased soluble sugars. K deficiency caused accumulation of soluble sugars and amino acids in roots, and decreased organic acids and amino acids in leaves. Notable metabolic pathway alterations included; (1) increased levels of α-ketoglutarate and raffinose family oligosaccharides in N, P or K-deficient tomato roots, and (2) increased putrescine in K-deficient roots. These findings provide new knowledge of metabolic changes in response to mineral deficiencies.

Effect of Suboptimal Nutritional Status on Mineral Uptake and Carbohydrate Metabolism in Tomato Plants

A suitable supply of mineral elements into shoot via a root system from growth media makes plants favorable growth and yield. The shortage or surplus of minerals directly affects overall physiological reactions to plants and, especially, strongly influences carbohydrate metabolism as a primary response. We have studied mineral uptake and synthesis and translocation of soluble carbohydrates in N, P or K-deficient tomato plants, and examined the interaction between soluble carbohydrates and mineral elements. Four-weeks-old tomato plants were grown in a hydroponic growth container adjusted with suboptimal N (0.5 mmol L -1 Ca(NO₃)₂ㆍ4H₂O and 0.5 mmol L-1 KNO₃), P (0.05 mmol L -1 KH₂PO₄), and K (0.5 mmol L -1 KNO₃) for 30 days. The deficiency of specific mineral element led to a significant decrease in its concentration and affected the concentration of other elements with increasing treatment period. The appearance of the reduction, however, differed slightly between elements. The ratios of N uptake of each treatment to that in NPK sufficient tomato shoots were 4 (N deficient), 50 (P deficient), and 50% (K deficient). The P uptake ratios were 21 (N deficient), 19 (P deficient), and 28% (K deficient) and K uptake ratios were 11 (N deficient), 46 (P deficient), and 7% (K deficient). The deficiency of mineral elements also influenced on carbohydrate metabolism; soluble sugar and starch was substantially enhanced, especially in N or K deficiency. In conclusion, mineral deficiency leads to an adverse carbohydrate metabolism such as immoderate accumulation and restricted translocation as well as reduced mineral uptake and thus results in the reduced plant growth.

Evaluation of Soil and Fertilizer Management Techniques Applied by Farmers in Forcing and Semi-forcing Cucumber Cultivation Facilities

These days, agricultural products cultivated in facilities occupy the highest percentage of agricultural output price. Specifically cucumbers have been one of the crops that farmers prefer to growing, because their prices were high. However, cucumber crop is sensitive to the soil and environments and it requires the exact crop management. In order to establish cultivation techniques for cucumbers, the current situation of cucumber cultivation was surveyed from ten cucumber farmlands; five farmlands of cucumber cultivation in forcing and five of semi-forcing practicing systems, respectably. The soil conditions were alluvial or valley in soil topology, moderately or poorly drainage in soil drainage classes, coarse loamy in soil texture family. Soil was managed with deep plowing combined with application of basal fertilizers such as compost, rice straw, oil cake, wood chip and chemical fertilizer. The whole soil was prepared in uniformly with rotary. Three major nutrients ()of basal application were 815-464-529 kg in forcing and 197-135-151 kg in semi-forcing cultivation. Top dressing of fertilizer was supplied in fertigation system of macro and micro elements in 2~3 day interval with water irrigation. The average yields of cucumbers were with 381,000 thousand won in average gross profit (AGP) in forcing cultivation and with 177,000 thousand won in AGP in semi-forcing cultivation. Cucumber production during the winter season was considered to increase the gross profit because cucumber price tends to stay in high level during this time. The accumulation of soil chemicals like EC, available and exchangeable cations could be controlled by rice straw application. The rice straw application increased soil temperature during the winter season, in exchange of soil air, and in extension of plant roots. In addition, the rice straw application somewhat affected decrease of salts accumulation.

Macro and Micro Nutrient Contents in Leaves of Greenhouse-grown Cucumber by Growth Stages

In order to estimate the inorganic nutrient content in cucumber leaves at respective growth stages under greenhouse conditions, we investigated five cucumber farms practicing a forcing cultivation system with nine-month growth period and another five cucumber farms practicing a semiforcing cultivation system with six-month growth period. The cucumber yield in forcing and semiforcing cultivation systems amounted to 14.8 ton and 10.7 ton , respectively. Soils between two different cultivation systems showed no significant differences in pH, organic matter contents and exchangeable cation contents during early growth stage, whereas EC, -N and available contents were higher in soils of semiforcing cultivation systems. Suitable soil temperature was well provided by forcing cultivation. The highest NPK contents in leaves were observed in 60~80 days after planting for forcing systems and in 100 days after planting for semiforcing systems. Thereby forcing cultivation systems showed somewhat higher NPK contents. Ca and Mg contents in cucumber leaves did not significantly change during the growth period in forcing systems, while semiforcing systems showed the highest contents of Ca and Mg in 80~100 days after planting. Fe, Mn and Zn contents in leaves also did not significantly change during the growth period, whereas Mn contents were slightly higher in forcing systems due to lower soil pH. B contents in leaves were higher in semiforcing systems because of higher available B contents in soil.

Physiological Responses to Mineral-Excessive Conditions: Mineral Uptake and Carbohydrate Partitioning in Tomato Plants

The shortage or surplus of minerals directly affects overall physiological metabolism of plants; especially, it strongly influences carbohydrate metabolism as a primary response. We have studied mineral uptake, synthesis and partitioning of soluble carbohydrates, and the relationship between them in N, P or K-excessive tomato plants, and examined the interaction between soluble carbohydrates and mineral elements. Fourweeks-old tomato plants were grown in a hydroponic growth container adjusted with excessive N (20.0 mmol L -1 Ca(NO₃)₂?4H₂O and 20.0 mmol L -1 KNO₃), P (2.0 mmol L-1 KH₂PO₄), and K (20.0 mmol L-1 KNO₃), respectively, for 30 days. Shoot growth rates were significantly influenced by excessive N or K, but not by excessive P. The concentrations of water soluble N (nitrate and ammonium), P and K were clearly different with each tissue of tomato plants as well as the mineral conditions. The NPK accumulation in all treatments was as follows; fully expanded leaves (48%) > stem (19%) = roots (16%) = petioles (15%) > emerging leaves (1). K-excessive condition extremely contributed to a remarkable increase in the ratio, which ranged from 2.79 to 10.34, and particularly potassium was dominantly accumulated in petioles, stem and roots. Fresh weight-based soluble sugar concentration was the greatest in NPK-sufficient condition (154.8 mg g -1 ) and followed by K-excessive (141.6), N-excessive (129.2) and P-excessive (127.7); whereas starch was the highest in K-excessive (167.0 mg g -1 ) and followed by P-excessive (146.1), NPK-sufficient (138.2) and N-excessive (109.7). Soluble sugar showed positive correlation with dry weight-based total N content (p<0.01) whereas was negatively correlated with soluble P (p<0.01) and dry weight-based total P (p<0.01). On the other hand, starch production was negatively influenced by total N (p<0.001), but, it showed positive relation with total K concentration (p<0.05). This study shows that uptake pattern of NPK and production and partitioning of soluble carbohydrate were substantially different from each mineral, and the relationship between water soluble- and dry weight-based-mineral was positive.

Temporal Changes in N Assimilation and Metabolite Composition of Nitrate-Affected Tomato Plants

The role of inorganic nitrogen assimilation in the production of amino acids, organic acids and soluble sugars is one of the most important biochemical processes in plants, and, in order to achieve normally, nitrate uptake and assimilation is essential. For this reason, the characterization of nitrate assimilation and metabolite composition from leaves, roots and xylem sap of tomato (Solanum lycopersicum) was investigated under different nitrate levels in media. Tomato plants were grown hydroponically in liquid culture under five different nitrate regimes: deficient (0.25 and 0.75 mM NO 3 -), normal (2.5 mM NO 3 -) and excessive (5.0 and 10.0 mM NO 3 -). All samples, leaves, roots and xylem sap, were collected after 7 and 14 days after treatment. The levels of amino acids, soluble sugars and organic acids were significantly decreased by N-deficiency whereas, interestingly, they remained higher in xylem sap as compared with N-normal and -surplus. The N-excessive condition did not exert any significant changes in metabolites composition, and thus their levels were similar with N-normal. The gene expression and enzyme activity of nitrate reductase (NR), nitrite reductase (NIR) and glutamine synthetase (GS) were greatly influenced by nitrate. The data presented here suggest that metabolites, as a signal messenger, existed in xylem sap seem to play a crucial role to acquire nitrate, and, in addition, an increase in α-ketoglutarate pathway-derived amino acids under N-deficiency may help to better understand plant C/N metabolism.

Responses of nutrient uptake, carbohydrates and antioxidants against low temperature in plants

Abstract : Recently, a quick drop of air temperature in plastic film houses by adverse weather conditions leads to the occurrence of low temperature damages to growing crops. Chilling injury, defined as a variety of growth restriction occurring below the optimal temperature, is one of environmental factors strongly affecting crop growth and yield. Low temperature causes the restricted evapotranspiration, reduced mineral uptake (P > K > NO 3- ), and an increase in electrolyte leakage such as K. Despite being different with plant species, an accumulation of soluble carbohydrates such as glucose, fructose, sucrose and starch under chilling condition is well known. A variety of environmental stresses are known to cause oxidative damage to plants either directly or indirectly by triggering an increased level of production of reactive oxygen species (ROS), and, to combat the oxidative damage, plants have the antioxidant defense systems comprising of enzymes, SOD, POD, CAT, GPX and APX, and non-enzymes, ascorbate, gluthathione, α-tocopherol, phenolic compounds, carotenoid and flavonoids. The aim of this review is to provide basic information to build chilling-indicators and optimal nutrition management under adverse temperature conditions as broadly considering mineral uptake, carbohydrate metabolism and antioxidative defense system.

Source-Sink Partitioning of Mineral Nutrients and Photo-assimilates in Tomato Plants Grown under Suboptimal Nutrition

A huge number of greenhouse soils in Korea have accumulated mineral elements which induce many nutritional and pathological problems. The present study was performed to the effects of the reduced fertilization on plant growth, and uptake and partitioning of minerals (N, P, K) and soluble carbohydrates using highly minerals-accumulated farmer’s greenhouse soil. On the basis of the recommended application for tomato crop, the application rates of N, P and K were 110(50%)-5.2(5%)-41.5(35%)kg ha -1 , respectively, using Hoagland’s nutrient solution. Tomato growth rates during the whole experiment were not significant between treatments, but it was found that a decrease in daily growth represented after 60 days of treatment (DAT). The reduced application led to a drastic decrease in the concentration of N, P and K in fruits, and, thus, this resulted in lower uptake after 40 DAT. The lower phloem export and utilization of soluble carbohydrates caused an accumulation of extra-carbohydrates in leaves, stems and fruits in the reduced application. The reduced fertilization induced the capture of N, P and K in leaves and of soluble carbohydrates in stems compared to the conventional application. In this study, we suggest that it is possible to delay the first fertigation time in minerals-accumulated soils without an adverse impact on crop growth, but it is necessary to regularly monitor mineral status in soil to ensure a balanced uptake, synthesis and partitioning of minerals and carbohydrates.

Physiological Responses of Tomato Plants and Soil Microbial Activity in Salt Affected Greenhouse Soil

Crop productivity decreases globally as a result of salinization. However, salinity impact on greenhouse-grown crops is much higher than on field-grown crops due to the overall concentrations of nutrients in greenhouse soils. Therefore, this study was performed to determine the short-term changes in growth, photosynthesis, and metabolites of tomato plants grown in greenhouse under heavily input of fertilizers evaluated by microbial activity and chemical properties of soils. The soils ( 10.01 dS m -1 ) from farmer’s greenhouse fields having different fertilization practices were used. Results showed that the salt-accumulated soil affected adversely the growth of tomato plants. Tomato plants were seldom to complete their growth against > 10.0 d Sm -1 level of EC. The assimilation rate of CO2 from the upper fully expanded leaves of tomato plants is reduced under increasing soil EC levels at 14 days, however; it was the highest in moderate or high EC-subjected (3.0 ~ 10.0 dS m -1 ) at 28 days. In our experiment, soluble sugars and starch were sensitive markers for salt stress and thus might assume the status of crops against various salt conditions. Taken together, tomato plants found to have tolerance against moderate soil EC stress. Various EC levels ( -1 ) led to a slight decrease in organic matter (OM) contents in soils at 28 days. Salinity stress led to higher microbial activity in soils, followed by a decomposition of OM in soils as indicated by the changes in soil chemical properties.