Potassium starvation affects biomass partitioning and sink–source responses in three sweet potato genotypes with contrasting potassium-use efficiency

2018 ◽  
Vol 69 (5) ◽  
pp. 506 ◽  
Author(s):  
Jidong Wang ◽  
Guopeng Zhu ◽  
Yue Dong ◽  
Hui Zhang ◽  
Zed Rengel ◽  
...  

Rooted single leaves of sweet potato (Ipomoea batatas L.) produce and translocate photosynthates, thus representing an ideal model for characterising the source–sink relationships and responses to various environments. A hydroponics culture study was conducted with rooted single leaves of sweet potato to determine intraspecific variation in growth, biomass partitioning, and associated physiological changes in response to variable potassium (K) supply among genotypes Ji22 (low K-use efficiency), Nan88 (high K-uptake efficiency) and Xu28 (high K-use efficiency). Potassium deficiency suppressed biomass accumulation in blades, petioles and roots in all three genotypes. Root length of diameters <0.25 mm and 0.25–0.5 mm was significantly less for K-deficient than K-sufficient roots of all genotypes, but the difference was proportionally greater in the K-inefficient genotype Ji22 than the other two genotypes. Potassium deficiency also severely inhibited net photosynthesis of blades in Nan88 and Ji22, as well reducing photosynthate translocation, increasing starch, hexose and sucrose concentrations, and decreasing K concentration in blades. The genotypes varied in photosynthesis-related responses to the K deficiency. Xu28 had greater blade K concentration and net photosynthesis as well as stable maximum quantum yield of photosystem II (FV/FM, with FV = FM – F0) under K deficiency, possibly because of a better source–sink balance and more efficient translocation of photosynthates to roots and K to blade compared with genotypes Ji22 and Nan88. Impaired phloem loading during K deficiency was associated with a decline in photosynthetic rate and decreased carbohydrate supply from blades, resulting in restricted root growth.

2017 ◽  
Vol 211 ◽  
pp. 147-154 ◽  
Author(s):  
Ji dong Wang ◽  
Pengfu Hou ◽  
Guo peng Zhu ◽  
Yue Dong ◽  
Zhang Hui ◽  
...  

Author(s):  
Amsalu Gobena Roro ◽  
Mihret Tesfaye

Introduction: The sweet potato (Ipomoea batatas Lam.), is one of the root and tuber crops grown from low land to high land region of Ethiopia. However, its productivity depends on adaptability and tolerance to different environmental stresses and the capacity of the crop to enhance water use efficiency under moisture stress conditions. The objective of this study was to evaluate impact of irrigation interval on morpho-physiological characteristics of sweet potato varieties. Methodology: The trial was a 3 x 2 factorial arrangement in CRD design consisting: three irrigation intervals (daily-control), four days and seven days interval) combined with two sweet potato genotypes (Hawassa-83 and Kulfo) with three replications. Results: The morpho-physiological indicators, morphological traits, water use efficiency (WUE), Relative leaf water content (RLWC), leaf gas exchange, stomata density, and tuber yield were evaluated. The result indicated that morphological traits were significantly (P≤0.05) responded to genotype and irrigation frequencies. As compared to daily irrigation, an extended watering interval to seven days irrigation interval significantly reduced leaf number, vine length, branch number and internode length by 55.42, 19.83 cm, 2.17 and 0.35 cm, respectively. Stomata density was strongly responded to genotypes than effect of irrigation frequency. Genotype Hawassa-83 had approximately 2.0 more stomata per mm2 than genotype Kulfo regardless to irrigation frequency. The interaction effect between genotype and irrigation frequency revealed significant influence on photosynthesis and transpiration rate. The rate of assimilate accumulation was significantly reduced (by 9.97


2016 ◽  
Vol 67 (11) ◽  
pp. 1168 ◽  
Author(s):  
Qifu Ma ◽  
Richard Bell

Although soil salinity and potassium (K) deficiency are widespread in agricultural lands, there is a paucity of knowledge about the interactive effects of sodium (Na) and K on the growth and yield of major grain crops. In pot experiments, we examined salt tolerance of canola (Brassica napus L.), narrow-leafed lupin (Lupinus angustifolius L.) and wheat (Triticum aestivum L.), and crop K requirement under Na supply ranging from low to high. Plant growth and seed yield of all three crops were lower at 40 mg K/kg than at 100 mg K/kg soil. Although 100 mg Na/kg (4 dS/m in soil solution) had little effect on canola cv. Boomer and wheat cv. Wyalkatchem, the salt-treated narrow-leafed lupin cv. Mandelup died at 47 days after sowing, regardless of amount of soil K. In low-K soils, canola with 100 mg Na/kg and wheat with 50 mg Na/kg did not show K-deficiency symptoms and produced greater seed yield than plants with nil Na addition. At 100 mg K/kg, Na-induced reduction in growth and yield occurred only to plants with 200 mg Na/kg. However, at 160 mg K/kg, 200 mg Na/kg did not have an adverse effect. In canola and wheat, shoot K concentration increased and shoot Na concentration decreased with increasing amount of soil K; however, high soil K did not reduce shoot Na concentration in narrow-leafed lupin. The study showed that narrow-leafed lupin was very susceptible to salinity, whereas canola and wheat plants were relatively salt-tolerant. The stimulation of growth and yield in canola and wheat by low–moderate Na in low-K soils suggests partial K substitution by Na, and that adaptation of canola and wheat to salt-affected soils can be enhanced by high K supply.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 492d-492
Author(s):  
Jonathan N. Egilia ◽  
Fred T. Davies ◽  
Sharon Duray

Hibiscus plants, were irrigated with full strength Hoagland's nutrient solution containing either 0,2,5, or 10 mM potasium(K). After 72 days of K treatment, half of the plants at each K level were subjected to a 21-day slowly developing drought stress cycle and the other half were non-drought stressed (ND). Mid-day leaf water potentials at day 21 was-1.5 to-1.6 MPa (DS), and -0.5 MPa (ND). Leaf K concentration increased with increasing K in nutrient solution for both DS and ND plants, but K was higher in DS than ND plants at 2.5 and 10 mM K. Of the macronutrient cations, only (Ca) was inversely correlated with nutrient solution K, in both DS and ND plants. Leaf concentrations of all the micronutrient cations increased with increasing K supply, regardless of drought stress. Potassium hadt significant positive correlation with total plant and leaf dry weight of DS, but not ND plants. Leaf stable carbon isotope composition (δ13 C,an estimate of long term water-use efficiency), was positively correlated with N, Mg and Ca, and negatively correlated with K, iron (Fe), and K:total cation ratio regardless of drought stress. Both net photosynthesis and stomatal conductance were negatively correlated with N and Ca, but positively correlated with K, Fe and manganese in ND plants.


Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 99
Author(s):  
Esteban Burbano-Erazo ◽  
Carina Cordero ◽  
Iván Pastrana ◽  
Laura Espitia ◽  
Evelin Gomez ◽  
...  

Sweet potato is a crop with a wide capacity to adapt to adverse conditions. To study the tolerance of the sweet potato to a low-altitude environment, 34 genotypes comprising three groups from different altitude conditions ranging from 18–599, 924–1298, 1401–2555 meters above sea level were evaluated. These genotypes were evaluated through ecophysiological parameters: net photosintetic rate (Pn), stomatal conductance (GS), transpiration (E), leaf internal CO2 (ICO2), vapor pressure deficit (VPD) and leaf internal temperate (LT). sSubsequently, water use efficiency (WUE) and carboxylation efficiency index (CEI) were estimated. Simultaneously, morpho-agronomic characterization of the genotypes was conducted including descriptors and morpho-colorimetric parameters. A wide ecophysiological variability was found among genotypes from high, intermediate and low altitudes, when those were evaluated under low altitude conditions. The genotypes that presented major soil coverage efficiency and leaf size showed greater Pn, WUE and CEI, and Low VPD and E, aspects that benefited the ability to form roots the under low-altitude environment. The altitudinal origin of the genotypes influenced the ecophysiological response under low altitude conditions. The capacity of certain sweet potato genotypes to tolerate low altitude conditions were due to to different mechanisms, such as certain morphoagronomic traits that allowed them to adjust their physiological processes, especially those related to photosynthesis.


Author(s):  
Cesar D. Fermin ◽  
Hans-Peter Zenner

Contraction of outer and inner hair cells (OHC&IHC) in the Organ of Corti (OC) of the inner ear is necessary for sound transduction. Getting at HC in vivo preparations is difficult. Thus, isolated HCs have been used to study OHC properties. Even though viability has been shown in isolated (iOHC) preparations by good responses to current and cationic stimulation, the contribution of adjoining cells can not be explained with iOHC preparations. This study was undertaken to examine changes in the OHC after expossure of the OHC to high concentrations of potassium (K) and sodium (Na), by carefully immersing the OC in either artifical endolymph or perilymph. After K and Na exposure, OCs were fixed with 3% glutaraldehyde, post-fixed in osmium, separated into base, middle and apex and embedded in Araldite™. One μm thick sections were prepared for analysis with the light and E.M. Cross sectional areas were measured with Bioquant™ software.Potassium and sodium both cause isolated guinea pig OHC to contract. In vivo high K concentration may cause uncontrolled and sustained contractions that could contribute to Meniere's disease. The behavior of OHC in the vivo setting might be very different from that of iOHC. We show here changes of the cell cytosol and cisterns caused by K and Na to OHC in situs. The table below shows results from cross sectional area measurements of OHC from OC that were exposed to either K or Na. As one would expect, from the anatomical arrangement of the OC, OHC#l that are supported by rigid tissue would probably be displaced (move) less than those OHC located away from the pillar. Surprisingly, cells in the middle turn of the cochlea changed their surface areas more than those at either end of the cochlea. Moreover, changes in surface area do not seem to differ between K and Na treated OCs.


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