烤烟钾素营养特性的基因型差异研究

以10个烤烟基因型为材料,进行了离子耗竭溶液培养、土壤耗竭盆栽试验和田间小区试验,研究比较钾素营养特性的基因型差异。结果表明,不同基因型的吸钾速率和耐低钾能力差异显著。吸钾速率以红大和K358最大,耐低钾能力Nc27NF和K358最强,Nc729最弱。10个基因型全株含钾量在低钾水平下变幅为0.87%～1.25%,而在高钾水平下为1.40%～1.94%。高钾条件下,基因型G28、77089-12、Rg11和Nc82的叶片含钾量高于2%;K358、Coker319、K346和Nc27NF有较高的钾素利用效率,K346、Nc729、G28和K358的钾素收获指数大于50%。各烤烟基因型的钾素营养特性在不同供钾条件下无显著相关性。综合比较K346属于钾高效基因型。     

K高效和K低效基因型水稻Na和K的吸收和分布与水稻生长及体内K利用率之间的关系

A pot experiment with two rice (Oriza sativa L.) genotypes differing in internal potassium use efficiency (IKUE) was conducted under different sodium (Na) and potassium (K) levels. Adding NaCl at a proper level enhanced rice vegetative growth and increased grain yield and IKUE under low potassium. Addition of higher rate of NaCl had a negative effect on the growth of the K-efficient rice genotype, but did not for the K-inefficient genotype. Under low-K stress, higher NaCl decreased IKUE of the K-efficient rice genotype but increased IKUE for the K-inefficient genotype. At tillering stage and under low-K stress, adding NaCl increased K and Na contents and decreased the ratio of K/Na for both genotypes. At harvesting stage under low-K stress, adding NaCl increased K and Na contents and K/Na ratio for the K-efficient genotype but decreased the K/Na ratio for the K-inefficient genotype. The accumulated Na was mostly deposited in the roots and sheaths. At tillering stage, the K and Na contents and the K/Na ratios in different parts for both genotypes decreased in the following sequence: K⁺ in sheaths > K⁺ in blades > K⁺ in roots; Na⁺ in roots > Na⁺ in sheaths > Na⁺ in blades; and K/Na in sheaths >> K/Na in roots. The K-efficient genotype had a lower K/Na ratio in roots and sheaths than the K-inefficient genotype under low-K stress. At harvesting stage, K and Na contents in grains were not affected, whereas K/Na ratio in the rice straws was increased for the K-efficient genotype but decreased for the K-inefficient genotype by Na addition. However, this was not the case under K sufficient condition.     

GROWTH AND BIOMASS PARTITIONING IN TOMATO IN RELATION TO RATIO OF NITROGEN:PHOSPHORUS SUPPLY

Tomato (Lycopersicon esculentum) plants were grown in hydroponic culture with nitrogen (N): phosphorus (P) supply ratios from 18:1 to 2:1. Nitrate and phosphate were supplied daily in pre-set ratios to maintain a constant P concentration, giving varying degrees of N limitation. Plant dry weight, weights of plant fractions and N and P concentrations in plant parts were measured at 9 and 18 days. Relative growth rate was related to ratio of N:P supplied, with higher ratios giving a higher growth rate, but a noticeably reduced rate was only apparent at 4:1 and 2:1 ratios. Relative growth rate was largely independent of internal N and P concentrations, although there was an optimum internal N:P ratio of approximately 14:1. The plants took up N and P at rates adjusting towards this 14:1 ratio. Depressed relative growth rate of plants inadequately supplied N was linearly correlated with decreased shoot fraction.     

小麦-玉米轮作系统下长期施钾对作物产量、钾素利用率和钾素平衡的影响

Sustainable potassium (K) management at different soil sites requires understanding the relationships between crop productivity and long-term K fertilizations on a regional or national scale.We analyzed responses of grain yield of wheat (Triticum aestivum L.) and maize (Zea mays L.),K efficiency,and partial balance (difference between K input through fertilizer and K output in the aboveground biomass) during 15-(1990-2005) or 18-year (1990-2008) K fertilizations at five distinctive agroecological zones across China.Compared to the inorganic nitrogen (N) and phosphorus (P) fertilization,the inorganic NPK fertilization significantly increased grain yields of wheat (21%) and maize (16%-72%) at Qiyang and Changping,where soils have low exchangeable and non-exchangeable K contents,but not at rmqi,Yangling and Zhengzhou,where soils have a high exchangeable and non-exchangeable K and/or low N/K ratio in crop plants.Compared to the inorganic NPK fertilization,the inorganic NPK (30% N) and organic manure (70% N) fertilization (NPKM) increased grain yields of wheat (14%-40%) and maize (9%-61%) at four sites,but not at Zhengzhou.For a productivity of wheat at 2-5 t ha-1 or maize at 3-6 t ha-1,13-26 or 9-17 kg K ha-1 were required to produce 1.0 t wheat or maize.The NP fertilization resulted in the lowest negative partial K balance and accumulated 52 kg K ha-1 year-1 less than the NPK fertilization,which accumulated 28 kg ha-1 year-1 less K than the NPKM fertilization.A re-evaluation of the site-specific fertilization effects on N/K ratio in crop plants and soil K accumulation under current NPK and NPKM fertilization is urgently needed to increase both crop yield and K use efficiency at different agroecological zones across China.     

砂培筛选体系中不同小麦品种对磷的吸收和利用率

A sand-based culture system using rock phosphate(P)was developed to simulate the situation in alkaline soils,with respect to the dominant P form,and five wheat cultivars(Excalibur,Brookton,Krichauff,Westonia and Sunco)were tested in this screening system to compare their P uptake and utilisation efficiencies.Results showed that these cultivars differed significantly in their ability to acquire P from the sparingly available form(rock phosphate in this case).The accumulation of P by Brookton was three times that by Krichauff.P concentrations in plant tissues did not differ signifficantly,indicating that all cultivars were similar in P utilisation efficiency.A further experiment showed that the greater ability of a cultivar to take up P from sparingly available form was related to the ability of a cultivar to acidify the rhizosphere.Seed P content was a confounding factor in this system,and the use of relatively uniform seed with similar Pcontent,preferably low,was conducive to a successful outcome of the screening process.     

氮素对玉米幼苗生长、根系形态及氮素吸收利用效率的影响

采用水培试验,比较分析了氮素对高产玉米杂交种幼苗生长、根系形态及氮素吸收利用效率的影响。结果表明,在一定氮素范围内供氮量的增加能够促进玉米地上部的生长,也促进东单90（DD90）和沈玉21（SY21）根系干重的增加,而高量供氮会抑制根系的生长,导致根冠比下降。郑单958（ZD958）在8.0 mmol/L氮水平下地上部受抑制的程度大于根系,造成根冠比有所增加。在各氮素水平下,东单90具有很好的根系形态,提高了氮素的吸收能力,从而提高氮素积累量。随氮浓度的增加,玉米植株氮素吸收效率增大而氮素生理利用效率减小,无论在低氮还是高氮条件下,郑单958和东单90的氮素吸收效率均显著高于沈玉21和郝育12（HY12）,氮素生理利用效率却显著低于沈玉21和郝育12。不同品种对氮素的响应存在显著差异,东单90和郑单958耐低氮和对氮素吸收的能力强,郑单958耐高氮能力相对较弱,沈玉21和郝育12对氮素需求量大,耐低氮能力弱。适宜的氮素供应能更好地协调根系与地上部的关系,促进根系形态发育,增加根系对氮素的接触面积,促进根系对氮素的高效吸收。     

INTERACTION BETWEEN POTASSIUM CONCENTRATION AND ROOT-ZONE TEMPERATURE ON GROWTH AND PHOTOSYNTHESIS OF TEMPERATE LETTUCE GROWN IN THE TROPICS

Lactuca sativa L. plants were grown at three root-zone temperatures (RZTs): 25°C, 30°C and ambient RZT (A-RZT) on an aeroponic system. Three potassium (K) concentrations: ?25% (minus K), control (standard K), and +25% (plus K) were supplied to plants at each RZT. Plants grown at the plus K and 25°C-RZT had the highest productivity, largest root system and highest photosynthetic capacity. The minus K plants at 25°C-RZT had the highest shoot soluble carbohydrate (SC) concentration, but they had the highest root SC concentration in the plus K plants at A-RZT. However, the highest starch concentration was found in both shoots and roots of the plus K plants at 25°C-RZT. The plus K plants had the highest shoot K concentration at 25°C-RZT, but they had the highest root K concentration at A-RZT. Highest proportion of absorbed K was partitioned to shoots when the plants were grown with the plus K at 25°C-RZT.     

EVALUATING POTASSIUM-USE-EFFICIENT COTTON GENOTYPES USING DIFFERENT RANKING METHODS

Identification of cotton (Gossypium hirsutum L.) genotypes efficient in potassium (K) uptake and utilization, under K-deficient conditions represents a cost-effective and environmentally friendly approach for low-K-input agriculture. It would reduce the costly input of K-fertilizers and manage K resources in agro-ecosystems. We ranked 25 cotton genotypes for their K use efficiency under deficient and adequate K regimes in hydroponics, using two different methods. K deficiency generally reduced cotton growth; however, K-efficient genotypes accumulated more biomass due to higher K uptake. Genotype NIBGE-2 exhibited excellent adaptation potential in terms of high shoot dry weight under both K regimes and ranked as the only most desirable, “efficient-responsive” genotype. Genotype CIM-506 produced low shoot dry weight under low K condition and ranked as “non-efficient.” Genotype Desi okra produced low shoot dry weight at adequate K level and ranked as “non-responsive.” Genotype ranking using two different methods ensured the validity of results.     

Potassium Soil Test Calibration for Lowland Rice on an Inceptisol

Potassium (K) plays an important role in many physiological and biochemical processes in plants and its adequate use is an important issue for sustainable economic crop production. Soil test–based K fertilizer recommendations are very limited for lowland rice (Oryza sativa L.) grown on Inceptisols. The objective of this study was to calibrate K soil testing for the response of lowland rice (cv. Ipagri 109) to added K. A field experiment was conducted in the farmers' field in the municipality of Lagoa da Confusão, State of Tocantins, central Brazil. The K rates used were 0, 125, 250, 375, 500, and 625 kg K ha^?1 applied as broadcast and incorporated during sowing of the first rice crop. Rice responded significantly to K fertilization during 2 years of experimentation. Maximum grain yield of about 6,000 kg ha^?1 was obtained with 57 mg K kg^?1 soil in the first year and with 30 mg K kg^?1 in the second year. This indicated that at low levels of K in the soil, nonexchangeable K was available for plant growth. Potassium use efficiency designated as agronomic efficiency (kg grain produced/kg K applied) decreased significantly in a quadratic fashion with increasing K level in the soil. Agronomic efficiency had a significantly linear association with grain yield. Hence, improving agronomic efficiency with management practices can improve rice yield.     

Influence of Biomass Partitioning and Nutrient Uptake on Yield of Arecanut Grown on a Laterite Soil

The present investigation was conducted on a laterite soil to study biomass partitioning and nutrient-uptake pattern in the aboveground parts of arecanut palm and their relationships to yield. Total biomass production was significantly greater in high-yielding plants (43.6 kg palm^?1) than in low-yielding plants (30.8 kg palm^?1). Total standing biomass of trunk accounted for 69–74% of the total aboveground biomass in arecanut palm. Dry-matter partitioning to kernel was only 4–10% of the total biomass. The uptake of major nutrients varied significantly between low- and high-yielding plants. Calcium (Ca) uptake was greater by trunk than by other parts, while magnesium (Mg) accumulation was similar in trunk and leaf. The uptake of micronutrients by aboveground parts except leaf was significantly different between low- and high-yielding plants. The present study indicated that combined effect of greater biomass production and nutrient uptake had direct impact on marketable yield of arecanut.     

Potassium Substitution by Sodium in Root Medium Influencing Growth Behavior and Potassium Efficiency in Cotton Genotypes

ABSTRACT

Potassium (K) deficiency affects cotton (Gossypium hirsutum L.) growth. Sodium (Na) can substitute K for some non-specific functions in plants. Four cotton genotypes were evaluated for their growth rates and K use efficiency grown at various K:Na. The cotton genotypes and treatments had significant (p < 0.01) effect on biomass production, growth rate related parameters, K use efficiency, and K: Na ratio. Maximum total dry matter (2.57 g plant^-1) was accumulated by ‘NIBGE-2’ and minimum (1.91 g plant^?1) was by ‘FH-1000’. Maximum K:Na ratio in shoot was obtained by ‘MNH-786’ and minimum was by ‘NIBGE-2’when 1/3rd K was replaced with Na. Genotypes and various treatments significantly (p < 0.05) influenced specific utilization rate (SUR) and K transport rate (KTR). There was a significant relationship (R² = 0.84, n = 60) between shoot dry matter and K: Na ratio in shoot. Overall, the growth was better when K and Na were added in ratio of 3:1.     

Potassium release characteristics and mineralogical characteristics of some delaware soils

Abstract

Twenty‐eight agriculturally important Delaware soils were cropped intensively in a greenhouse experiment. There was no consistent positive correlation between K uptake and percent sand, silt, clay, clay minerals of the clay fraction, K‐feld‐spars of the sand fraction or K‐feldspar weathering of the soils from the A horizon. Only potassium feldspar from the sand fraction and K‐feldspar weathering correlated with K uptake in the soils of the B horizon. This correlation was only significant at the latter part of the experiment when nonexchangeable K was probably the source of plant available K.