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1.
To determine the genotypic variation in response to salt (NaCl) stress in cotton (Gossypium hirsutum L.) seedlings, potassium (K+) and sodium (Na+) homeostasis, photochemical energy utility, reactive oxygen metabolism and the activity of antioxidant enzymes were comparatively analyzed in three cotton cultivars (CCRI 49, CCRI 35 and Z 51504) under salt constraint. The results showed that NaCl treatment significantly inhibited biomass accumulation, and the extent of inhibition was highest in CCRI 49 and lowest in Z 51504. Salinity caused an ion imbalance in plants but ion homeostasis was less pronounced in Z 51504, as it accumulated more K+ and less Na+. Experiments of salt shock treatment were tested using a non-invasive micro-test (NMT) system, which also revealed that Z 51504 had lower Na+ influx and better K+ retention. Salinity increased excess-energy dissipation [non-photochemical quenching (qN) and photorespiration rate (PR)], but depressed photochemical efficiency such as photosynthesis rate (Pn), quenching (qP), photochemical quantum yield of photosystem (ΦPSII) and electron transport rate (ETR). As a result, more electrons were driven to other sinks, for example decreasing ETR/Pn and increasing the O2? generation rate. However, the superior tolerance of Z 51504 had a better balance of photochemical energy under salt conditions, displayed higher photochemical efficiency and excess-energy dissipation. Furthermore, the antioxidant enzyme activities were also affected by salt stress and less effectively removed reactive oxygen species. The antioxidant enzyme activities of Z 51504 were higher than those of CCRI 49 and CCRI 35, which resulted in lower levels of reactive oxygen species (ROS) and mitigated the salt-induced membrane lipid peroxidation. The overall results indicated that more effective retention of ions, photochemical energy utility and ROS-removing capability were probably the main reasons for the stronger salt tolerance in Z 51504.  相似文献   

2.
An experiment with factorial arrangement of treatments on a randomized complete block (RCB) design basis with three replications was conducted in a greenhouse during Spring 2010 to investigate changes in sodium ion (Na+), potassium ion (K+), Na+/K+ and to determine proline, protein content, and superoxide dismutase (SOD) of four wheat and four barley cultivars. Three salt levels {1, control (no salt), 7, and 13 dS m?1 [2.5 and 5 g salt [sodium chloride (NaCl) and sodium sulfate (Na2SO4) in 1:1 ratio] per kg of soil, respectively]} were used in this investigation. Salt stress treatments were applied 4 weeks after planting (at 2 leaf stage). Leaf samples were taken four weeks after imposition of salt treatment. The results showed that salinity caused an increased in proline and protein content, and SOD in all wheat and barley cultivars. The highest proline and protein content of barley and wheat cultivars at all salinity levels were observed in ‘Nimrooz’ and ‘Bam’ cultivars, respectively. At all salinity levels, wheat and barley cultivars ‘Kavir’ and ‘Nimrooz’, respectively, had the lowest Na+ content. Barley cultivar ‘Kavir’ and wheat cultivar ‘Bam’ had higher K+ and K+:Na+ ratios. This might be related to salt tolerance in these two cultivars. Wheat and barley cultivars showed differences with regard to proline, protein, and SOD content, Na+, K+, and K+:Na+ ratio, indicating existence of genetic diversity among the cultivars. These findings indicated that higher K+, K+:Na+ ratio, proline, protein, and SOD content could be the key factors, which offer advantage to barley over wheat for superior performance under saline conditions.  相似文献   

3.
Net uptake and partitioning of sodium (Na+) and potassium (K+) in plants of two sesame cultivars (Sesamum indicum cv. ‘PB-1’ and cv. ‘UCR’) exposed to 20 mM sodium chloride (NaCl) were studied over a period of 28 days. Both cultivars showed a marked discrimination between K+ and Na+ during uptake. The reduction of K+ in the plants caused by the NaCl treatment was of similar magnitude in the two cvs. The cv. ‘UCR’ showed lower Na+ concentrations in the shoot tissues than ‘PB-1’ and K+/Na+ selectivity ratios were higher in cv. ‘UCR’ than in cv. ‘PB-1’. At the last sampling on day 28 there was a marked decrease of shoot growth in cv. ‘PB-1’ in comparison to the cv. ‘UCR’. Leaves of cv. ‘PB-1’ showed clear toxic symptoms, while those of cv. ‘UCR’ did not. It is concluded that Na+ exclusion from the shoot contributes to salt tolerance of sesame, cv. ‘UCR’.  相似文献   

4.
Potassium (K) deficiency is one of the main limiting factors in cotton (Gossypium hirsutum L.) production. To study the mechanism of high K‐use efficiency of cotton, a pot experiment was conducted. The experiment consisted of two cotton genotypes differing in K‐use efficiency (H103 and L122) and two K‐application levels (K0: 0 g (kg soil)–1; K1: 0.40 g (kg soil)–1). Root‐hair density and length, partitioning of biomass and K in various organs, as well as K‐use efficiency of the two cotton genotypes were examined. The results show that there was no significant difference in K uptake between the two genotypes at both treatments, although the genotype H103 (high K‐use efficiency) exhibited markedly higher root‐hair density than genotype L122 in the K1 treatment. Correlation analysis indicates that neither root‐hair density nor root‐hair length was correlated with plant K uptake. Furthermore, the boll biomass of genotype H103 was significantly higher than that of genotype L122 in both treatments, and the K accumulation in bolls of genotype H103 was 39%–48% higher than that of genotype L122. On the other hand, the litter index (LI) and the litter K‐partitioning index (LKPI) of genotype H103 were 14%–21% and 22%–27% lower than that of genotype L122. Lastly, the K‐use efficiency of total plant (KUE‐P) of genotype H103 was comparable with that of genotype L122 in both treatments, but the K‐use efficiency in boll yield (KUE‐B) of genotype H103 was 24% and 41% higher than that of genotype L122 in K0 and K1 treatments. Pearson correlation analysis indicated that KUE‐P was positively correlated with BKPI and negatively correlated with LKPI, while KUE‐B was positively correlated with BKPI and boll‐harvest index (HIB), and negatively correlated with LKPI. It is concluded that there were no pronounced effects of root‐hair traits on plant K uptake of the two genotypes. The difference in K‐use efficiency was attributed to different patterns of biomass and K partitioning rather than difference in K uptake of the two genotypes.  相似文献   

5.
施钾对不同基因型棉花光合特性及产量和品质的影响   总被引：7，自引：3，他引：7  
在田间条件下,研究了施钾对抗虫杂交棉中棉所38、抗虫棉新棉33B、常规棉中棉所12光合特性和产量及品质的影响。结果表明,与不施钾相比,不同基因型棉花施氯化钾225.kg/hm2,棉花叶面积指数(LAI),叶绿素荧光动力学参数PSⅡ最大光化学量子效率(Fv/Fm)、PSⅡ潜在光化学活性(Fv/Fo)、PSⅡ实际光化学效率(ФPSⅡ),叶片净光合速率(Pn)、气孔导度(Gs),棉花干物重及分配到生殖器官的比例,棉花总成铃数、铃重和衣分均有不同程度提高;中棉所38、新棉33B和中棉所12皮棉产量分别增加13.60%、10.66%和4.21%;棉纤维2.5%跨距长度、比强度、马克隆值和纤维整齐度等品质也得到改善。中棉所38和新棉33B比中棉所12施钾的效果更好,生产上应优先给抗虫杂交棉和抗虫棉品种施用钾肥。  相似文献   

6.
ABSTRACT

The effect of salinization of soil with Na2SO4, CaCl2, MgCl2, and NaCl (70:35:10:23) on the biochemical characteristics of three wheat (Triticum aestivum L.) cultivars (‘LU-26S,’ ‘Sarsabaz’ and ‘Pasban-90’) was investigated under natural environmental conditions. Twenty-day-old seedlings of all three cultivars were subjected to three salinity treatments: 1.3 (control), 5.0, and 10 dSm?1 for the entire life period of plants. After 120 d of seed sowing, plant biomass production decreased by 49% and 65%, respectively, in response to 5 and 10 dSm?1 salinity levels. Addition of salts to growth medium also had a significant adverse effect on plant height. Increasing salinity treatments caused a great reduction in nitrate reductase activity (NRA) of the leaf. The inhibitory effect of salinity on nitrate reduction rate was more pronounced at the reproductive stage than at the vegetative stage of plant growth. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ showed less reduction in NRA due to salinity compared with ‘Pasban-90.’ Ascending salinity levels significantly reduced potassium (K+) and calcium (Ca2+) accumulation in shoots, while the concentration of sodium (Na+) was increased. Salts of growth medium increased the shoot nitrogen (N) concentration, whereas phosphorous (P) concentration of shoots was significantly reduced due to salinity. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ proved to be the salt-tolerant ones, producing greater biomass, showing less reduction in NRA, maintaining low sodium (Na+), and accumulating more K+ and Ca2+ in response to salinity. These two cultivars also showed less reduction in shoot K+/Na+ and Ca+/Na+ ratios than in ‘Pasban-90,’ particularly at the 10 dSm?1 salinity level.  相似文献   

7.
Being macronutrient, K+ is involved in a number of metabolic processes including stimulation of over 60 enzymes. The present study was conducted to investigate whether K-priming could alleviate the effects of salinity on the growth and nutrient status of cotton seedlings. The seeds of two cotton cultivars, namely FH-113 and FH-87, were primed with solutions of three potassium sources (KNO3, K2SO4 and K2HPO4) using three concentrations (0%, 1.25% and 1.5%) of each potassium source. After 1 week of germination, the seedlings were subjected to salinity (0 and 200 mM NaCl) stress. The results showed that salinity significantly affected growth and nutrients status of cotton seedlings. The K-priming alleviated the stress condition and significantly improved dry matter as well as nutrient uptake in cotton seedlings. Of the priming treatments pre-sowing treatment with KNO3 (1.5%) was most effective in increasing shoot and root lengths and biomass of cotton seedlings. The seedlings raised from seed treated with KNO3 (1.5%) showed varied accumulation of cations (Ca2+, Na+ and K+) and faced less oxidative stress irrespective of cotton cultivars under salt stress. The results suggested that pre-sowing seed treatment with KNO3 (1.5%) might be recommended for synchronized germination and sustainable production of cotton crop under saline environments.  相似文献   

8.
Potassium (K) is one of the major mineral elements required for normal growth of cotton. However, understanding the effect of controlled‐release K fertilizer on leaf photosynthesis and K use efficiency (KUE) of cotton is currently limited. A two‐year pot experiment was consecutively conducted in 2014 and 2015 with three kinds of K fertilizer including K2SO4, KCl, and polymer‐coated KCl (CRK), each at four application rates (0.00, 0.86, 1.73, and 2.59 g K plant−1, respectively). For each type of K fertilizer, the yield and K uptake of cotton increased but the KUE decreased with higher K fertilizer application. The release characteristics of K from CRK corresponded well to the K requirements during cotton growth. Plant‐available soil K, as well as leaf SPAD values, net photosynthetic rate (Pn), maximal photochemical efficiency (Fv/Fm), and effective quantum yield of photosystem II (ΦPSII) in CRK treatments were increased after full bloom stage compared to conventional K fertilizers under the same potassium application rate. Consequently, the CRK treatments significantly increased lint cotton yields by 8.1–32.7% and 3.7–20.8%, while the KUE increased by 15.5–54.8% and 14.5–45.4% compared to KCl and K2SO4 treatments, respectively. The results indicate that the application of CRK is intensively recommended to replace conventional potassium fertilizers for gaining greater yields and higher KUE of cotton.  相似文献   

9.
Genotypic differences in potassium (K) uptake and utilization were compared for eight cotton cultivars in growth chamber and field experiments. Four of the cultivars (‘SGK3’, ‘SCRC18’, ‘SCRC21’ and ‘SCRC22’) typically produce lower dry mass and the other four (‘Nannong8’, ‘Xiangza2’, ‘Xinluzao12’ and ‘Xiangza3’) produce greater dry mass in K-deficient solution (0.02 mM). The mean dry weight of seedlings (five-leaf stage) of cultivars with greater biomass was 155% higher than that of cultivars with lower biomass yield under K deficiency. However, all the genotypes had similar dry matter yields in K-sufficient solution (2.5 mM). Thus, the four cultivars with superior biomass yield under low K medium may be described as K efficient cultivars while the inferior cultivars may be described as K inefficient. Although seeds of the studied cultivars originated from different research institutes or seed companies, there were little differences in seed K content among them, irrespective of their K efficiency. Consequently, there were no significant differences in K accumulation in seedlings (4 d after germination in a K-free sand medium) just before transferring to nutrient solutions. However, the K efficient genotypes, on average, accumulated twice as much K at 21 d after transferring to K-deficient solution (0.02 mM). A much larger root system as well as a slightly higher uptake rate (K uptake per unit of root dry weight) may have contributed to the higher net K uptake by the K efficient cultivars. In addition, the K efficiency ratio (dry mass produced per unit of K accumulated) and K utilization efficiency (dry mass produced per unit of K concentration) of the K efficient cultivars exceeded those of the K inefficient genotypes by 29% and 234%, respectively, under K deficiency. On average, the K efficient cultivars produced 59% more potential economic yield (dry weight of all reproductive organs) under field conditions even with available soil K at obviously deficient level (60 mg kg?1). We noted especially that the four K inefficient cultivars studied were all transgenic insect-resistant cotton, suggesting that the introduction of foreign genes (Bt and CpTI) may affect the K use efficiency of cotton.  相似文献   

10.
ABSTRACT

The effects of three sodium chloride (NaCl) levels (0, 1200, and 2400 mg kg? 1 soil) and three irrigation intervals (3, 7, and 14 d) on the growth and chemical composition of two Pistacia vera rootstocks (‘Sarakhs’ and ‘Qazvini’) were investigated under greenhouse conditions. Eight-week-old pistachio seedlings were gradually exposed to salt stress which afterward, water stress was initiated. At any irrigation interval, plant height and shoot and root dry weights of both rootstocks were reduced with increasing salinity. However, increasing irrigation intervals alleviated the adverse effects of soil salinity. A negative relationship observed between relative shoot growth and electrical conductivity of soil saturation extract (ECe) confirmed the above findings. Under 3-d irrigation interval, the ECe required to cause a 50% growth reduction was lower than those under 7- and/or 14-d irrigation intervals. Shoot and root chemical analyses indicated that the salinity as well as irrigation regime affected the concentration and distribution of sodium (Na+), potassium (K+), and chloride (Cl?) in pistachio. The concentration of Na+, K+ and C1? ions increased with a rise in NaCl level, and was generally declined with increasing irrigation interval. Based on plant height, shoot and root dry weights and the concentrations of Na+, K+, and C1? in the plant tissues, at lowest irrigation intervals ‘Sarakhs’ shows a higher sensitivity to soil salinity than ‘Qazvini’, but with increasing irrigation interval, ‘Sarakhs’ and ‘Qazvini’ can be classified as resistant and sensitive to salinity, respectively.  相似文献   

11.
Bermudagrass (Cynodon dactylon) is a salinity-tolerant turfgrass that has good use potential in the saline-alkali lands of warm regions. However, the systematic Na+ and K+ regulation mechanisms under salinity stress remain unclear at the whole plant level. Two bermudagrass cultivars differing in salinity tolerance were exposed to 0, 50, 100, 200, or 300 mM NaCl in a hydroponic system. Growth, absorption, transportation, and secretion of Na+ and K+, and gas exchange parameters were determined in both cultivars. K+ contents were decreased and Na+ contents and Na+/K+ ratios were increased in both bermudagrasses with increased salinity; however, lower Na+ content and Na+/K+ ratio and more stable K+ content were found in the leaves of the salinity-tolerant ‘Yangjiang’ than the salinity-sensitive ‘Nanjing’. Higher Na+ contents in root cortical cells were found than in the stele cells of ‘Yangjiang’, but the opposite was observed in ‘Nanjing’. Lower Na+ contents and higher K+ contents were found in vessels for ‘Yangjiang’ than for ‘Nanjing’. Salinity stress increased the selective transport of K+ over Na+ from roots to leaves and the Na+-selective secretion via salt glands, which were stronger in ‘Yangjiang’ than ‘Nanjing’. Net photosynthetic rate and stomatal conductance decreased in the two bermudagrasses with increased salinity; however, they were more stable in ‘Yangjiang’. The results suggested that bermudagrass could reduce Na+ accumulation and maintain K+ stability in leaves under salinity stress by restricting Na+ into vessels in roots, selectively transporting K+ over Na+ from roots to leaves, selectively secreting Na+ via leaf salt glands, and maintaining suitable stomatal conductance.  相似文献   

12.
嫁接对不同棉花基因型钾效率的影响   总被引：1，自引：0，他引：1  
采用全生育期土培盆栽试验,在研究2个棉花基因型钾吸收效率和利用效率的基础上,对未嫁接和经嫁接的自根苗(接穗和砧木为同一基因型)处理的棉花干物质和钾的积累、分配进行比较。结果表明:自根苗植株与未嫁接植株相比,不同棉花基因型在不同钾水平下干物质和钾的积累及分配不同。高效基因型103经过嫁接后营养器官中的干物质和钾比例增加,生殖器官中的干物质和钾减少,产量和钾利用指数下降;低效基因型122经过嫁接后营养器官中的干物质和钾比例减少,生殖器官中的干物质和钾增加,产量和钾利用指数升高。吸收效率因钾水平而异,高效基因型103嫁接后施钾时吸收效率降低,缺钾时升高;而低效基因型122嫁接后施钾时吸收效率升高,缺钾时降低。嫁接对不同棉花基因型产生的效应不同,通过嫁接使不同棉花基因型物质分配趋于平衡。  相似文献   

13.
Two cultivars ("Spirit”; and “Jubileo") of maize (Zea mays L.) were studied to compare their response to various levels of potassium (K+) (0.1, 1, and 6 mol/m3) and sodium chloride (NaCl) (0 and 50 mol/m3) in nutrient solutions with 16 h photoperiod, day/night temperature regime of 25/20°C, and a photon flux density of 380 nmol/m2/sec. ‘Spirit’ produced about 1.5 times more biomass than ‘Jubileo’ at 6 mol/m3 K+in the control treament, while at 0.1 mol/m3 K+ the growth of both cultivars was similar. Plant fresh weight was reduced by 20% in ‘Spirit’ and by 30% in ‘Jubileo’ with 50 mol/m3 NaCl and 6 mol/m3 K+. Growth reduction of maize plants by salinity was associated with an excessive accumulation of sodium (Na+) and chloride (Cl‐) rather than an effect on water relations. The higher salt tolerance of ‘Spirit’ can be related to its greater capacity to exclude Na+ and Cl‐ from the leaves and to maintain a higher K+/Na+ ratio. Increasing the K+ supply in the rooting media did not improve growth reduction imposed by the 50 mol/m3 NaCl treatment. ‘Jubileo’ had a lower turgor potential than ‘Spirit’. High concentrations of Na+ in the leaves may help to maintain turgor, but cannot substitute for K+ to give adequate growth of maize. The accumulation in leaf tissue of inorganic ions was sufficient for osmotic adjustment in both cultivars and no single organic solute appears to be important in this process.  相似文献   

14.
ABSTRACT

The effects of saline water containing 0, 50, 100, and 150 mM sodium chloride (NaCl), and 100 mM NaCl + 100 mM potassium (K) on photosynthesis, water relations, and ion and carbohydrate content of olive (Olea europaea L.) cultivars ‘Koroneiki’ and ‘Mastoidis’ were studied on five-year-old trees. Salinity increased sodium (Na+) and chloride (Cl?) in tissues of both cultivars, but more so in ‘Koroneiki’ than in ‘Mastoidis.’ Salt-toxicity symptoms were observed at 100 and 150 mM, but not in plants receiving extra K. In salt-stressed plants, leaf water potential declined, whereas turgor potential remained positive due to a rapid decrease in osmotic potential. Salinity increased mannitol content up to 41.3% in ‘Mastoidis’ and 15.8% in ‘Koroneiki’, but reduced starch content in leaves. Photosynthetic rates fell significantly with increasing salinity in both cultivars, but more so in ‘Koroneiki’ than in ‘Mastoidis’. Potassium supplements reduced the concentration of Na+ and increased the concentrations of K+ in leaves, but decreased photosynthesis.  相似文献   

15.
ABSTRACT

A pot experiment was conducted to examine the uptake of nutrients (K+ (potassium) and Ca2+ (calsium)) and heavy metal (Cu2+ (copper) and Pb2+ (lead)) ions by leaves, seeds, and roots of two black gram [Vigna mungo (L.) Hepper] cultivars, ‘Mash-95018’(V1) and ‘Mash-97’(V2) treated with copper (Cu) and lead (Pb) at 25mg L?1 and 50mg L?1. This study was conducted in a greenhouse in the Botanical Garden, University of Agriculture, Faisalabad, Pakistan, during the spring of 2003. Heavy-metal treatments were applied 30 d after germination, and nutrient and heavy-metal ion uptake data were collected 10 d after treatment application. Both heavy metals in both cultivars substantially reduced nutrient ion accumulation and its translocation to seeds. Leaves had proportionately more K+ and Ca2+ than that recorded for roots and seeds after heavy-metal treatments. Nevertheless, both heavy metal (Cu2+ and Pb2+) ions ware predominantly sequestered in the roots, rather than in leaves and seeds, under their respective treatments. As the external concentrations of heavy metals increased, their uptake by the respective treated plants also increased, but nutrient ion (K+ and Ca2+) uptake was gradually reduced. This result suggests a concentration-dependent phenomenon. Overall, lead (Pb2+) showed more toxic effects on the uptake of essential nutrients compared with Ca2+, while ‘Mash-97’proved more sensitive to heavy metals than ‘Mash-95018.'  相似文献   

16.
Screening of potassium efficient genotypes will be one of the best ways to solve the low potassium content of flue-cured tobacco. The study was conducted to determine whether the potassium efficient genotypes could be screening with high K+ uptake efficiency. The K+ uptake characteristics of a high K+ content line (GK8) and the conventional cultivated variety (K326) of flue-cured tobacco were compared at the seedling stage. Km, Cmin, and Imax values were higher in young seedlings (4?～?5 versus 6?～?7 leaf stage) and cultures with high initial K+ concentration (0.35 versus 0.25?mmol?L?1). Culture solutions with a high K+ concentration (2.0 versus 0.6?mmol?L?1) showed a high Km, and Cmin, but the Imax was lower as compared with the young seedlings and the solution with high initial K+ concentration. In conclusion, the GK8?line had a stronger ability for limited K+ uptake than K.  相似文献   

17.
Salinity of irrigation water reduces yield and juice quality in sugarcane (Saccharum spp. hybrids), but cultivars vary in the degree of reduction. Genotypes which accumulate more potassium (K+) may be more resistant to salinity than genotypes that accumulate less K+. We examined the effect of irrigation water salinity on yield and juice quality in a cultivar with high conductivity, high K+ juice, ‘NCo 310’, and a cultivar with low conductivity, low‐K+ juice, ‘TCP 87–3388 ‘. Plants were grown in lysimeters containing 793 L of soil and irrigated with water of 0.01, 1.25, 2.93, or 4.70 dS m‐1. Quality and component analyses were conducted on the juice of single stalks subdivided by length, and the juice from whole stalks. The two cultivars responded similarly to increased salinity, although juice of NCo310 had a higher mineral concentration, especially K+ and Cl‐. Yield and most quality components were not significantly reduced by 1.25 dS m‐1 water. The 2.93 and 4.70 dS m‐1 treatments reduced stalk height and weight but not stalk numbers. The reduction in stalk height was due to decreases in number of internodes per stalk and mean internode length. Increasing salinity reduced total soluble solids and sucrose in juice, but increased Na+, K+, Mg+2, Ca+2 and Cl‐ Within a stalk, sucrose increased from top to bottom, while K+ decreased. Sodium concentrations were sharply higher in the lowest section, especially in plants irrigated with saline water. Chloride concentration was approximately equal in all sections. An increase in K accumulation did not appear to increase the salt tolerance of NCo310.  相似文献   

18.
Rice (Oryza sativa L.) is one of the most sensitive crops to drought, salt and cold stresses, particularly at post germination stage. The effects of these stresses on some physiological responses of two (a salt tolerant and a sensitive) rice cultivars ‘FL478’ and ‘IR29’ were investigated in this study. Two-day seedlings were transferred to MS media complemented with iso-osmotic concentrations of sodium chloride (NaCl; 0, 50, 100, and 150 mM) or mannitol (0, 100, 180, and 275 mM) at 25°C or four and 15°C for 10 days. Experiments were carried out based on completely randomized design, with at least three replicates. All three stresses decreased shoot growth, chlorophylls, carotenoids and root starch while increased shoot soluble sugars. The effect of exerted cold stress on growth, hydrogen peroxide (H2O2) and malonyldialdehyde levels, electrolyte leakage, chlorophylls and carotenoids contents was more than or comparable with drought, but greater than salinity. The results also indicated higher tolerance of ‘‘FL478’’ not only to salinity but also to drought compared to ‘‘IR29’’. Therefore, a mechanism for osmotic stress adjustment is probable in ‘‘FL478’’ in addition to low sodium (Na+) to potassium (K+) ratio in shoot tissues under salinity.  相似文献   

19.
In order to study the effects of salinity and water stress on growth and macronutrients concentration of pomegranate plant leaves, a factorial experiment was conducted based on completely randomized design with 0, 30, and 60 mM of salinity levels of sodium chloride and calcium chloride (1:1) and three irrigation intervals (2, 4, and 6 days) with 3 replications on ‘Rabab’ and ‘Shishegap’ cultivars of pomegranate. The results of the shoot and root analysis indicated that the salinity and drought affected the concentration and distribution of sodium (Na+), potassium (K+), chloride (Cl?), calcium (Ca2+), magnesium (Mg2+), and phosphorus (P+) in pomegranate leaves. Mineral concentrations of sodium (Na+), chloride (Cl-), potassium (K+), in shoots and roots were increased with increasing salinity. Drought treatments increased the concentration of Cl?, Na+, and Mg2+ in the shoot. Both cultivars showed significant differences in the concentrations of elements, however the most accumulation of Na+ and Cl? was observed in ‘Rabab,’ while the ‘Shishegap’ cultivar had the most absorption of K+. ‘Shishegap’ cultivar showed higher tolerance to salinity than ‘Rabab’ through maintaining the vegetative growth and lower chloride transport to the shoot, and improvement of potassium transport to shoot.  相似文献   

20.
不同铵钾比对高铵下拟南芥地上部和根系生长的影响   总被引：1，自引：0，他引：1  
宋海燕  李光杰  施卫明 《土壤》2016,48(6):1077-1084
钾在缓解植物铵毒害的过程中起着重要的作用。本文研究了高铵(30 mmol/L)条件下,不同铵钾比(7.5︰1和150︰1)对拟南芥(Col-0)主根、侧根以及地上部生长的影响。结果表明:30 mmol/L NH4+条件下,高铵钾比(150)处理显著加重了拟南芥铵毒害现象,地上部和根系生长所受的抑制作用更为明显并导致更严重的氧化胁迫。相比低铵钾比水平,在高铵处理下,高铵钾比使得拟南芥主根伸长量降低57.4%,侧根数量减少33.3%,而地上部鲜重减轻69.9%。DAB(3,3￠-二氨基联苯胺,3,3￠-diaminobenzidine)叶片染色结果表明,不加铵处理下,外源不同钾水平(0.2和4.0 mmol/L)对拟南芥叶片的氧化胁迫作用没有显著差异;而高铵处理下,相比低铵钾比处理,高铵钾比显著增加了叶片中过氧化氢的含量,加重了其氧化胁迫。伊文思蓝(Evans blue,EB)染色结果表明,不加铵处理下,外源不同钾水平对拟南芥地上部和根部的膜透性没有显著差异,而高铵处理下,高铵钾比显著增强了拟南芥地上部和根部的膜透性,表明其对细胞的伤害程度加重。可见,高铵抑制拟南芥根系和地上部生长,高铵钾比则会加重这种抑制,其原因除了高浓度钾能减少植物对铵的吸收外,可能与高铵钾比条件加剧了植物的氧化胁迫有关。因此,适宜的铵钾比在植物应对铵毒害的过程中发挥重要作用。  相似文献   

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