基质中添加适宜玉米秸秆促进马铃薯脱毒苗生长

马铃薯微型薯常用栽培基质中,草炭是不可再生的,可供利用的资源有限。蛭石一般可使用一年,重复利用率低,且生产成本高。在马铃薯微型薯栽培基质中,玉米秸秆基质还未得到有效利用,玉米秸秆资源丰富,价格低廉。该试验对玉米秸秆基质在马铃薯微型薯生产上的应用效果进行了研究,通过比较分析试验结果,以期找到玉米秸秆在马铃薯微型薯栽培基质上较适宜的应用比例。该试验以马铃薯‘春薯四号’脱毒苗为试验材料,将玉米秸秆进行发酵腐熟,草炭过1 cm筛后,用玉米秸秆、草炭、蛭石、沙子、田园土5种基质材料按照不同体积比混配成6种复合基质,分别为M1(草炭:蛭石=1:1)、M2(玉米秸秆:草炭:蛭石=1:1:2)、M3(玉米秸秆:草炭:沙子=1:3:4)、M4(玉米秸秆:草炭:沙子=1:1:2)、M5(玉米秸秆:沙子:田园土=3:4:1)、M6(玉米秸秆:田园土=3:2)。基质材料按比例混配均匀后使用50%的多来宝可湿性粉剂500倍液和50%的多菌灵可湿性粉剂1 000倍液进行杀虫灭菌。将试验棚内土地耙平整,地面上方铺设防虫网,用砖砌9个2.4 m×1 m(长×宽)的试验槽,槽间过道宽40 cm,将每个试验槽分隔成2个面积相等的试验小区,共18个,每个小区面积1.2 m2。采用随机区组试验设计,设3次重复试验。马铃薯脱毒苗定植前在试验棚上方放置透光率为50%的遮阳网,待马铃薯脱毒苗缓苗期过后将其取下。从马铃薯脱毒苗定植开始每隔15 d进行随机采样,测定指标,分析比较6种不同配比基质对马铃薯脱毒苗形态指标株高、茎粗、叶片数、茎节数、地上部分及地下部分鲜质量的影响,及生理指标叶绿素a、叶绿素b、叶绿素总量、根系活力的影响。结果表明:M2(玉米秸秆:草炭:蛭石=1:1:2)的更有利于马铃薯脱毒苗的生长,缓苗时间短,植株较健壮,其中株高、茎粗、地下部鲜质量增长量多于其他基质,叶绿素a、叶绿素总量增长稳定且优于其他基质,可以有效地为微型薯的生长发育积累更多营养物质。     

Tuber formation as influenced by the C : N ratio in potato plants

Increasing the tuber number per plant and promoting tuber formation are important goals for potato production. Thus, it is of significance to understand how environmental factors affect tuber formation, which relates to the development of agronomical practices. The objective of this research was to test whether changing the CO₂ or N supply level could alter the C : N ratio in potatoes, and whether a change of the C : N ratio in potatoes closely correlates with tuber formation in potato plants. Potato plantlets were grown in greenhouse with varied CO₂ or N levels. The C and N concentrations of plants were measured, and the tuber number and tuber weight were recorded after different growth times. The results show that the C : N ratios in the potato plants increased with increasing CO₂ concentration and that potato plants treated with higher CO₂ concentrations form tubers earlier. A decrease in the N supply also resulted in a higher C : N ratio and earlier tuber formation. Therefore the hypothesis proposed previously is supported by the present work. In addition, the results that C concentration in plants remained stable under different CO₂ or N levels imply that the variation of C : N ratio in the potato plants is mainly due to a change of N concentrations which decreased as the environmental CO₂ concentration increased, while increased as the N supply level increased.     

Development of field-grown potato plants derived from meristem plants multiplied with different methods

Abstract

In the current multiplication technique first-generation seed tubers produced in the field by transplanting plants raised on peat in plastic rolls from plants cultured by repetitive multiplication using tip- and stem-cuttings and truncated plants are compared with in vitro micro-plants from the aspect of obtaining optimal-sized, disease-free seed tubers.

The objective of the study is to compare the dynamics of total plant dry mass and tuber dry mass of field-grown potato plants, and analyse the effect of the year and variety. Two local late-maturing potato varieties, Ants and Vigri, were used in the study. The field experiments were carried out in 2005–2007.

Significant impact of the multiplication method and experimental year on total plant dry mass and tuber dry mass was observed. The plants multiplied in vitro from micro-cuttings produced lower total dry mass and also lower tuber dry mass per m². The plants multiplied by tip- and stem-cuttings as well as truncated plants proved to be more adaptable to unfavourable weather conditions than in vitro plants; in a favourable year, however, the differences were insignificant. In the early phase of growth the ratio of the tuber dry mass to total plant dry mass increased more rapidly in the case of in vitro plants, whereas by the end of the growing season the relevant ratio was similar for all multiplication methods and years.

All developed multiplication methods are suitable for practical seed potato production in the field and ensure a reasonable potato crop.     

密度调控方式对马铃薯块茎大小调控功能初探

2014年和2015年分别以尤金和克新13号脱毒原种为供试材料,采用随机区组设计,分别设置6万穴/hm~2、9万穴/hm~2、12万穴/hm~2播种穴数和1、3个主茎/穴(2014年)以及6万穴/hm~2、8万穴/hm~2、10万穴/hm~2播种穴数和1、2个主茎/穴(2015年)等处理,研究密度调控方式对马铃薯块茎大小分布及产量的影响。两年试验结果表明:增加播种穴数或单穴主茎数都将增加30~150 g的块茎产量,降低150 g以上的块茎产量。早熟品种尤金的种薯生产采用12万穴/hm~2、3主茎/穴的播种方式,并于苗后60 d左右收获,可获得较高150 g以下块茎产量;商品薯生产采用6万穴/hm~2、3主茎/穴的播种方式可获得较高商品薯产量。中晚熟品种克新13号的种薯生产采用8万穴/hm~2、2主茎/穴的播种方式,苗后80 d左右收获,可获得较高150 g以下块茎产量;商品薯生产采用6万穴/hm~2、2主茎/穴的播种方式可获得较高商品薯产量。     

Risk assessment for volunteer and seedling GM potatoes in the northernmost European growing areas

Abstract

Commercial production of genetically modified (GM) potatoes (Solanum tuberosum L.) could represent a risk to conventional production if volunteer plants develop from tubers or true seeds that survive until the following growing season. We studied such risks under northernmost European conditions and monitored the effects of cultivar, tuber size and tuber depth in the soil on winter survival at MTT Agrifood Research Finland, Jokioinen (61°06′N, 23°02′E) from 2004–2007. Tubers of two non-GM cultivars, Saturna and Asterix, and two size classes, 25–30 mm and 45–50 mm, were planted at depths of 10 and 20 cm in autumn, soon after harvest. In winters 2004–2005 and 2005–2006 all tubers planted in the soil in autumn were killed by frost. In 2005–2006, the field was covered by up to 30–40 cm of snow and the minimum soil temperatures ranged between ?0.4^oC and ?0.9^oC, but only 0.0–3.5% of the tubers survived and there was no difference between cultivars, tuber sizes and planting depths. Under laboratory conditions compared with ?2.0°C and ?2.5°C, treatment at ?3.0°C for 72 h resulted in significantly lower survival rate of the tubers (8.2%). Asterix, a late maturing table potato cultivar, was more resistant to low temperatures than the processing cultivar Saturna. In general, volunteer tubers are not currently a significant risk for coexistence of GM and conventional potato production in northern Europe due to the cold winter conditions but also due to possibilities to control the sporadic volunteers from the next crop. However, we noted that seedlings initiated from true potato seed are able to produce tubers despite the short growing season. Such a risk could be reduced by accepting only non-berry-producing GM cultivars for cultivation.     

Potato tuber yield and quality in response to different nitrogen fertilizer application rates under two split doses in an irrigated sandy loam soil

Abstract

Management strategies to minimize nitrogen (N) losses to the atmosphere and water bodies from potato production fields while maintaining tuber yields and quality relies on good N management. A 2-year (2016–17 and 2017–18) field trial with ‘Symphonia’ potato was completed on a sandy loam soil irrigated with flood irrigation in Punjab, Pakistan to investigate the effect of N fertilizer rate on vegetative, yield and tuber quality parameters. The N fertilizer treatments comprising six N rates from 0 to 300?kg ha^?1 were applied at 50?kg N increments. Number of stems and tubers plant^?1 showed a quadratic response while other parameters revealed cubic trends in response to N fertilizer rates. Applying more than 250?kg ha^?1 of N fertilizer did not increase vegetative growth and yield. In conclusion, the optimal N-application rate of 250?Kg ha^?1 has great potential to improve yield and quality of potato in the sub-tropical region of Punjab, Pakistan. These findings, besides improving productivity can minimize the risk of N fertilizer loss to the atmosphere.     

Potato growth and nutrient diagnosis as affected by systemic pesticide and physiological growth stage

Abstract

Growth and chemical composition of crop plants may be subject to alteration by systemic compounds employed for pest control. A field study was implemented to examine the effects of aldicarb on growth, chemical composition, and nutrient diagnosis of a potato crop at various growth stages. Aldicarb use resulted in increased dry matter production of leaves, stems, and tubers, and final fresh tuber weight during the second year of the study. Higher tuber yields were likely due to greater photosynthetic capacity because the increase in leaf dry matter production with time was greater in the aldicarb treatment than in control. Leaf nutrition was not influenced by aldicarb; however, leaf nutrient content varied greatly with growth stage. Similar nutrient status evaluations were generated by DRIS, regardless of pesticide treatment or growth stage. DRIS was able to diagnose nutrient limitations as early as tuber initiation     

Rhizobacteria: Influence of cultivar and soil type on plant growth and yield of potato

The influence of potato cultivar and soil type on effectiveness of plant growth-promoting rhizobacteria (PGPR) was examined. Rhizobacteria were isolated from potato roots and tubers obtained from fields with a history of high potato yields. Fluorescent pigment-producing rhizobacteria. identified as strains of Pseudomonas putida and P. fluorescens, were selected for their antibiosis against Erwinia carovotora ssp. carotovora and growth-promoting activity on potatoes. In greenhouse tests, treatments of potato seedpieces and stem cuttings increased shoot dry weight from 1.23- to 2.00-fold and root dry weight from 1.27- to 2.78-fold. Survival of PGPR in the rhizosphere was monitored using antibioticresistant strains. Populations of these strains decreased from 3.6 × 10⁹ cgu g^?1 dry root weight to 4.5 × 10⁵ cfu g^?1 dry root weight 4 weeks after treatment. In field trials, PGPR strains were applied to seedpieces of cultivars Kennebec, Pungo, Red Pontiac and Superior and planted in Cape Fear loam. Plymouth loamy sand or Delanco sandy loam. Significant yield increases of 1.17–1.37-fold over controls were observed in two of three field trials. Variability in plant growth-promoting activity was observed between greenhouse and field trials, and no given treatment combination of PGPR strain, potato cultivar and soil type was consistently better than another.     

Metal concentrations,growth, and yield of potato produced from In Vitro plantlets or microtubers and grown in municipal solid‐waste‐amended substrates

In vitro plantlets or microtubers (in vitro produced tubers) of ‘Spunta’ potato (Solanum tuberosum L.) were planted in a 3 soil: 2 peat moss: 1 sand substrate (by volume) amended with municipal solid waste (MS W) compost at 0, 10, 20, or 30 g 4^‐1 L pot. Three months later, plant growth and tuber yield were evaluated and concentrations of shoot and tuber tin (Sn), arsenic (As), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), manganese (Mn), cadmium (Cd), and iron (Fe) were determined. Amending with MSW resulted in significant increases in concentrations of all tested metals in the substrate. Number of proliferated shoots of plants started from rooted plantlets was greatest at 10 g pot^‐1 MSW, whereas shoot weight of plants started from microtubers was greatest at 10 and 20 g pot^‐1 MSW. Tuber yield of plants started from rooted plantlets or microtubers was greatest at 10 or 30 g pot^‐1 MSW, respectively. In all instances, amending with MSW at 30 g pot^‐1 resulted in significant increases in concentrations of all tested metals in shoots and tubers. Concentrations of shoot Ni and tuber Zn and Fe for plants started from rooted plantlets and concentrations of shoot Fe and tuber As, Cu and Pb for plants started from microtubers increased consistently with increasing MSW percentage of the substrate. Plants started from rooted plantlets produced shoots with sufficient Zn, Mn, and Ni concentrations regardless of the substrate but with toxic Cu content at 30 g pot^‐1 MSW. Plants started from microtubers produced shoots with sufficient Mn and Ni concentrations regardless of the substrate but with low Zn and deficient Cu in unamended substrates. All plants had shoot Fe content higher than the sufficiency range. Although there were significant differences in concentrations of some nutrients among MSW treatments, no symptoms of nutrient toxicity or deficiency were observed. In all instances, tested elements did not accumulate in tubers to levels hazardous to human health. Concentrations of Cd, the most hazardous element, in potato tubers was not high enough to pose a threat to human. Our results indicate that there is a potential use of MSW in satisfying the needs of potato growth with negligible increases in heavy metal concentrations in tubers.     

Langstreckentransport von Calcium in Stolonen von Kartoffelpflanzen

Long-distance transport of calcium in stolons in potato plants In potato plants grown in water culture the influence of the tuber growth rate and the Ca supply to the tubers as well as the effect of the relative humidity around the stolons and tubers on the ⁴⁵Ca translocation in the stolon was investigated. If the stolon tip or the tuber were supplied with additional exogenous Ca and the relative humidity around the stolon or tuber was very high then ⁴⁵Ca applied to the roots was translocated in a negligible amount into the stolon or tuber. Even when the supply of exogenous Ca to the tubers was low, the tubers exerted no “sink”-effect on the ⁴⁵Ca translocation within the stolon. Under conditions of high relative humidity around the stolon ⁴⁵Ca applied to the stolon surface was nearly exclusively translocated in direction of the shoot. In contrast, under low relative humidity around the stolon or tuber ⁴⁵Ca applied to the stolon surface or to the root system was translocated into the stolon tip and into the tuber. The results indicate that within the stolon Ca is exclusively translocated in the xylem. A “sink”-effect of the tuber on the Ca translocation into the stolon as well as within the stolon was not been observed.     

Soil and tuber calcium affecting tuber quality of processing potato (Solanum tuberosum L.) cultivars grown in Hokkaido,Japan

Calcium (Ca) nutrition for potato (Solanum tuberosum L.) is important to increase tuber Ca concentration and improve potato tuber yield and quality. High tuber Ca content among other benefits mitigates incidence of blackspot bruise through maintenance of membrane health and regulation of biochemical reactions that leads to potato tuber discoloration. However, growers avoid application of Ca fertilizer in potato production in the belief that it causes potato common scab in Hokkaido, Japan. This study was conducted in Hokkaido to determine the current status of soil Ca and tuber Ca content levels, and its effect in mitigating incidence of potato bruise. Soil and tuber samples were collected from 90 and 80 fields in Tokachi and Kamikawa districts, respectively, in 2013 and 2014. Soil samples were analyzed for base saturation, Ca saturation, and exchangeable Al. Tuber Ca content and susceptibility of tubers to bruising were also evaluated. This study found that (1) 81% and 76% of soils collected from Tokachi and Kamikawa district, respectively, were deficient in Ca level, (2) tuber Ca content was lower than the reported value (250 mg kg^?1) considered to mitigate incidence of bruise, and (3) incidence of bruise were influenced by both tuber specific gravity and Ca content. There is urgent need to apply Ca fertilizer to attain increased soil Ca levels and improve quality of tubers.     

Critical phosphorus concentrations in potato plant parts at two growth stages

Adequately evaluating the phosphorus (P) nutritional status of a potato crop is dependent upon sampling the appropriate plant part at a defined growth stage. To establish P critical concentration levels in various potato plant parts (leaves, stems, tubers, leaflets, and petioles) at two growth stages [20 and 50 days after plant emergence (DAE)], an experiment under Brazilian climatic and soil conditions was conducted using seven P treatment levels (0, 40, 80, 160, 320, 640, and 1,280 kg P₂O₅ ha^‐1) applied in a randomized complete block design with four replications. ‘Baraka’ potato tubers were seeded at a spacing of 0.80 x 0.30 m following agronomic cultural practices recommended for this crop. Phosphorus concentrations in all the potato plant parts were significantly affected by the P fertilizer rates applied. The highest correlation between the P concentration in the various plant parts and marketable yield and optimum profit yield was obtained for the petiole taken 20 days DAE. Critical P levels associated with optimum profit yield were lower than those for maximum marketable tuber yield, and they were, 0.41, 0.39,0.39,0.57, and 0.57 g P 100 mg^‐1 DM in the leaf, stem, tuber, petiole, and leaflet, respectively.     

Vermicompost and Vermiwash Minimized the Influence of Salinity Stress on Growth Parameters in Potato Plants

Potato (Solanum tuberosum L.) is the fourth major crop worldwide after cereals. Some producers use irrigation water with high salinity, which consequently decreases the agronomic yield and potato quality. The aim of this investigation was to determine the effect of vermicompost and vermiwash on plant growth and tuber yield and characteristic traits in Solanum tuberosum L. plants and tubers subjected to salinity stress. A surface response experimental design with three replicates using a central point and 15 treatments was used with vermicompost at 300, 580, and 860 g plant^?1; vermiwash at 5, 10, and 15 ml plant^?1; and salinity stress with 15, 20, and 25 mM of NaCl levels. Plant physiological measurements included plant height (cm), stem diameter (mm), and plant fresh and plant dry weight (g). Six months after planting, measurements on tuber fresh weight, pH, electric conductivity, and °Brix were carried out. The addition of vermicompost and vermiwash minimized the influence of salinity stress on growth parameters and tuber characteristics in potato plants. Vermicompost (580 g plant^?1) plus vermiwash (15 ml plant^?1) induced a greater plant height and stem diameter. Plants amended with vermicompost (860 g plant^?1), vermiwash (15 ml plant^?1), and salinity stress (15 mM) had higher pH values, whereas electrical conductivity value in potato tubers decreased.     

Nitrogen and Potassium Fertilization Responses of Potato (Solanum tuberosum) cv. Spunta

A potato field experiment was conducted for 2 consecutive years to determine the effects of nitrogen (N) and potassium (K) fertilization rates on the yield and quality of potato cv. Spunta cultivated on soil low in N and K. A 3?×?4 complete factorial experiment was used with three rates of nitrogen (330, 495, and 660 kg N ha^–1) and four rates of potassium (112, 225, 450, and 675 kg K₂Ο ha^–1). An additional treatment without fertilization was used as the control. On soils low in N and K, potatoes showed low yield response to K fertilizer. The greatest tuber yields for both years were achieved at 495 kg N ha^–1 and 112 kg K₂O ha^–1 (29.81 t ha^–1) and 225 kg ha^–1 (27.13 t ha^–1), respectively. Differences in mean fresh weight due to treatment application were not significant. Application of 495 kg N ha^–1 significantly reduced harvest index (the ratio of tuber dry weight to the total dry weight at harvest) compared to 330 kg N ha^–1, but at 660 kg N ha^–1 harvest index achieved the greatest significant value. Potassium fertilization had no significant influence on harvest index. Nitrogen rates positively influenced the number of tubers. The addition of 450 kg K₂O ha^–1 significantly enhanced the number of tubers compared to the lower K rates, and the number was significantly decreased by the application of 675 kg K₂O ha^–1. Tuber dry-matter concentration was significantly promoted by N fertilization in both cultivation years, but it was negatively affected by K fertilization in the first year of cultivation. There was no change in tuber N with N application, but N application strongly increased nitrate (NO₃) concentration, which fluctuated between 360 and 1382 mg kg^–1 wet mass. Tuber NO₃ was negatively correlated with tuber yield, indicating that high levels of NO₃ in tubers can adversely affect yield. Tuber response to K fertilization was not in accordance with the rate of applied nutrient.     

Seasonal changes and the effect of nitrogen- and potash-fertilization on the solanine and α-chaconine content in various parts of the potato plant

The concentration of solanine and α-chaconine in leaves and tubers decreased with the progress of the potato plant towards maturity. In stems an increase of these alcaloids up to the first part of the second stage of the vegetation period could be observed. With a higher level of nitrogen the concentration of both glycoalcaloids in leaves and stems increased, while in tubers a depression of the glycoalcaloid content was estimated. An increased level of potassium did not change markedly the concentration of glycoalcaloids in leaves and stems of the potato plant but decreased both alcaloids in the tuber.     

Accumulation of Lead and Arsenic by Potato Grown on Lead–Arsenate-Contaminated Orchard Soils

There are concerns of potential food chain transfer of metals in crops grown on lead–arsenate-contaminated soils. The objective of this study was to investigate lead and arsenic uptake by four potato (Solanum tuberosum L.) cultivars grown on lead–arsenate-contaminated soils with lead and arsenic concentrations ranging from 350 to 961 and 43 to 290 mg kg^?1, respectively. Yield was not reduced due to treatment. Potato tubers were washed thoroughly before peeling. Lead concentration in both peeled tubers and peel was below instrument detection limit. Arsenic concentration in peeled tubers grown on the lead–arsenate soils ranged from 0.24 to 1.44 mg kg^?1. Arsenic concentration was 60% higher in the peel than in the peeled tuber. The relatively high arsenic levels in the peel demonstrated that arsenic was taken up into the potato peel tissue. It is recommended that if potatoes are grown on these soils they should be peeled before consumption.

Abbreviations Pb, lead; As, arsenic; DW, dry weight; FW, fresh weight     

Effects of different nitrogen forms on potato growth and development

The objective of this study was to test if the effects of different nitrogen forms on potato growth depend on the plant growth stage. Plants from different potato cultivars were treated with different forms of nitrogen before tuber initiation and after tuber formation. A nitrification inhibitor was used to prevent the transformation of ammonium (NH₄⁺) to nitrate (NO₃^?). Plant growth, tuber formation, leaf area, leaf chlorophyll content, and tuber yield were assessed. The results obtained over 2 years indicate that plants treated with NO₃-nitrogen (N) before or at tuber initiation produced more tubers per plant than those treated with NH₄-N. However, plants treated with NH₄-N develop tubers earlier. Additionally, after tuber formation, plants treated with NH₄-N had better shoot growth than plants treated with NO₃-N. A larger leaf area with higher leaf chlorophyll content resulted in greater dry matter accumulation and higher tuber yield at harvest for plants treated with NH₄-N.     

Mycorrhizal influence on storage metabolites and mineral nutrition in seed propagated potato (Solanum tuberosum L.) plant

Abstract

Potato (Solanum tuberosum) showed a well-established mutualistic association with arbuscular mycorrhizal fungi. In the present study, earthen pots containing autoclaved soil were taken in which surface sterilized potato seeds were sown. The seed sowed earthen pots were inoculated by sterilized spores of arbuscular mycorrhizal fungi along with sterilized inoculated maize-root fragments, while the rest half of the seed filled pots, without any inoculation depicting control but were provided with non-inoculated maize root fragments. The inoculation was performed twice; first inoculation was done 3 days prior to sowing of potato seeds and second at the time of seedling emergence. Sampling of the inoculated as well as of control plants was performed at 20-day intervals till 80?days after tuber initiation. An increment in the level of metabolites as well as mineral nutrient was found in mycorrhizal inoculated potato tubers in contrast to non-inoculated. Our work demonstrates that inoculation has a great potential in enriching storage metabolites and nutrients in potato plant in low yielding soils.     

Cultivation of transgenic cyanophycin-producing potatoes does not negatively affect growth,reproduction and activity of the earthworm Lumbricus terrestris (L.)

A microcosm experiment was performed to investigate the effects of post-harvest potato tubers from transgenic cyanophycin-producing potatoes on Lumbricus terrestris (L.) activity and biomass, number of cocoons and their hatchability as well as the remaining cyanophycin content in soil and cast samples during a period of 80 days. Potato tubers from four transgenic potato events with different cyanophycin content in a range from 0.8 to 7.5% were compared to the near isogenic, non-transgenic control (Solanum tuberosum L. cv. Albatros) and a comparative potato cultivar (S. tuberosum L. cv. Désirée). One treatment with transgenic tuber residue but without earthworms was prepared as an additional control. Potato tuber loss from the surface of the microcosms was significantly higher in the treatments with transgenic potato tubers compared with non-transgenic treatments. It can be estimated that the earthworm contribution to potato tuber loss from the soil surface was approximately 61%. Mean number of cocoons in addition to the number of hatched cocoons varied from 2.6 to 6.2 and from 7 to 15 accounting for 45.2–83.35% hatchability, respectively, but no significant differences between the treatments were found. The same was true for the development of earthworm biomass in the various treatments. The cyanophycin content in soil samples was significantly higher when earthworms were present indicating that the cyanophycin content in the upper soil layer might have been enhanced through earthworm burrowing activity. Overall, it is concluded that tubers from transgenic cyanophycin potatoes are easily degradable and neither inhibit nor stimulate earthworm growth, reproduction, and activity.     

Tuber yield and allocation of nutrients and carbohydrates in potato plants as affected by limestone type and magnesium supply

Abstract

Magnesium (Mg) is a nutrient that affects the development of plants and is mainly supplied through liming performed to correct soil acidity. By acting on photosynthesis and influencing carbohydrate partitioning in the plant, supplementary Mg supplied through soil or foliar application can increase the yield and quality of potato (Solanum tuberosum L.) tubers. The aim of this study was to evaluate the effect of supplemental Mg fertilization by soil or foliar application on plant nutritional status, tuber yield, and carbohydrate partitioning in potato crops in soil corrected with calcitic and dolomitic limestones. The experiment was carried out in pots under greenhouse conditions with a randomized block design in a 2?×?3 factorial scheme with four replications. Dolomitic limestone application and supplemental Mg fertilization via soil increased the concentrations of this nutrient in potato leaves. Liming with dolomitic limestone reduced the uptake of Ca and K by plants, but supplemental Mg fertilization did not alter the uptake of Ca, Mg or K. Supplemental Mg fertilization did not increase plant growth and tuber yield, even when calcitic limestone was used to elevate the base saturation to 60%; the exchangeable Mg concentration in soil was 9?mmol_c dm^?3, and the Ca:Mg relationship was 3.7. Liming with dolomitic limestone or providing supplemental Mg fertilization did not increase sugar and starch partitioning to the tubers.