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1.
In this study we report the water release curve of a compost-based carrier for solid matrix priming and its effects on carrot seed germination. ‘Danvers Half Long’ and ‘Nantes Scarlet’ carrot (Daucus carota) seeds were primed for 7 d at 15°C in a carrier consisting of 5:1:5.7 sieved compost: hydrogel:distilled water (based on weight) equaling a water potential of ?1.0 MPa. Seeds were blended with carrier at 1:10, 1:20, 1:30, or 1:40 (based on weight) and compost priming was compared with a polyethylene glycol (PEG) priming procedure. Germination testing at 20-30°C (16-8 h) in darkness indicated that all compost priming treatments hastened seed germination more than PEG priming. Compost priming at 1:30 increased final germination percentage (FGP) for ‘Nantes Scarlet’ (FGP = 85%) compared to PEG primed (FGP = 72%) seeds but ‘Danvers Half Long’ FGP was similar for all treatments. For both cultivars, seeds that were compost primed had reduced G (days to 10% FGP) and G (days to 50% FGP) compared to PEG primed or nonprimed seed. For ‘Danvers Half Long’ carrot seeds, priming ratios of 1:30 reduced G values more effectively than all other treatments. For ‘Nantes Scarlet’ carrot seeds, G10 and G50 values were reduced similarly at all seed-to-carrier ratios. Compost primed seeds could be dried and stored for 35 d at 3 or 20-30°C (16-8 h) for ‘Danvers Half Long’ and for 35 d at 3°C for ‘Nantes Scarlet’ with no loss in priming benefit. We conclude that solid matrix priming with a compost based carrier is a satisfactory alternative to PEG priming to improve germination of carrot seed.  相似文献   

2.
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   

3.
We studied the effects of salinity stress on biomass production, photosynthesis, water relations, and activity of antioxidant enzymes in two cultivars of common bean (‘HRS 516’ and ‘RO21’). Seedlings were raised in nutrient solution supplemented with increasing concentrations of sodium chloride (NaCl) at 0, 50, and 100 mM. After 10 days of salinity treatment, the plants were sampled to determine the enzyme activity, protein content and dry biomass. Plant biomass and activities of most antioxidant enzymes were adversely affected by salinity stress. Leaf osmotic potential was found to be directly proportional to salt stress. The cultivar, ‘HRS 516’ accumulated less sodium (Na+) than ‘RO21’. Under salinity, superoxide dismutase (SOD) enzyme activity increased 3 folds in both bean cultivars (‘HRS 516’ and ‘RO21’) compared to other antioxidants (APX, CAT, and GR). While not neglecting other possible factors, photosynthesis and biomass remains reliable indicators of plant functioning in response to salinity stress.  相似文献   

4.
Abstract

In switchgrass (Panicum virgatum L.) cultivation, rapid and uniform germination is essential because it is one of the most promising candidates for biofuel production. Priming, a seed enhancement technique with solid carriers, can be a useful tool for improving germination characteristics of switchgrass seeds. The objective of this study was to determine the effectiveness of priming on three non-aged and aged switchgrass cultivars of ‘Cave in rock’ ‘Dacotah’, and ‘Kanlow’. Seeds were primed with a synthetic calcium silicate (MicroCel E) and water at 30°C for five days. Seed, carrier and water proportions were 1 g, 0.5 g, and 1.5 mL, respectively. There was a 5% point (pp, Cave in rock), 8 pp (Dacotah), and 19 pp (Kanlow) increase in primed seeds compared with non-treated control seeds. Furthermore, priming decreased mean germination time by 26–36% in all seeds compared with the non-treated control. Accelerated aging was induced by storing seeds for 0, 10, and 21 days at 42°C and 95% relative humidity (RH). Germination percentage decreased and mean germination time increased with the aging. These results suggest that priming is an effective technique to improve the performance of switchgrass cultivars.  相似文献   

5.
Abstract

Seed germination and subsequent changes in Chamecytisus palmensis were studied under water limiting conditions, imposed by increasing concentrations of polyethylene glycol (PEG-6000) (0, 5, 10, 15, 20, 25, and 30%). Six water stress conditions (C. palmensis. Seed germination was completely inhibited under the drought stress of 30% (?1.20?MPa). Similar to the seed germination, the growth of radicles and hypocotyls after seed germination was also restricted by PEG-simulated drought stress, especially when water potential was lower than ?0.12?MPa (25%). In the same way, the ratio of radicles and hypocotyls significantly decreased with the increase of PEG concentrations, demonstrating strong adaptability to drought stress. Moreover, the decline of radicles and hypocotyls lead to a decrease in the number of root hairs. This would seriously affect the water absorption ability of the young roots. It was concluded that drought stress might be one of the causes for obstructed natural regeneration of C. palmensis plantations on sandy land.  相似文献   

6.
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   

7.
The effect of exposure to different vanadium (V) concentrations was studied in Nicotiana tabacum L. (cv. ‘Burley’ and cv. ‘Virginia’). In both cultivars, the vanadium did not affect the percentage of germination but root and shoot growth was inhibited, especially with the 80 μM dose. An altered root morphogenesis in vanadium growth plants was observed at the end of the experiment. The highest V accumulation was found in roots and the results showed a direct correlation between V content and V supply (P?≤?0.01). The V concentrations did not modify nicotine content in the cv. ‘Burley’, but in the cv. ‘Virginia’ the highest nicotine content was found in vanadium exposed plants (P?≤?0.05). The results suggest that these V concentrations may have a possible elicitor effect on alkaloid synthesis in N. tabacum L. cv. ‘Virginia’, and that this cultivar has a higher V sensitivity than the cv. ‘Burley’.  相似文献   

8.
Two contrasting maize (Zea mays L.) cultivars, i.e. ‘Shaandan 9’ (S9) and ‘Shaandan 911’(S911) were investigated by examining foliar nitrogen (N) modulation of N metabolism, water status and plant growth under short-term moderate water stress (SMWS). On 10th day of SMWS, dry matter (DM), relative water content (RWC) and nitrate reductase activity (NRA) were significantly decreased, whereas concentrations of free proline (FP), glycinebetaine (GB) and soluble protein (SP) were increased in leaves of both cultivars. Cultivar S9 maintained greater DM, RWC and these N metabolism traits than S911 during SMWS. Foliar N application much more raised DM, RWC, NRA, and concentrations of all solutes measured under SMWS above control. These positive effects were more pronounced in S911 than those in S9 during SMWS. Greater correlations were performed amongst all parameters under SMWS than control. Hence, we suggest that foliar N should be firstly applied to drought sensitive cultivars under drought.  相似文献   

9.
Experiments involved the comparison of three procedures used to determine compost maturity/phytotoxicity. The three tests evaluated were the CCME germination test (1996), a modified Zucconi et al. (1981) extract and a direct seed procedure. Three different plant species and seven types of ‘composts’ were used. The species were cress (Lepidium sativum), radish (Raphanus sativus), and Chinese cabbage (Brassica chinensis). Germination and growth experiments were performed on three types of mature composts: 1) racetrack manure-food waste; 2) two different samples of municipal solid waste; and 3) racetrack manure-sewage sludge), two types of immature composts (farmyard manure-food waste and farmyard manure-yard waste-food waste], and a control (soil or water). Four replicates for each species, ‘compost’ and test procedure were evaluated. The study concluded that the commonly used compost extract test and the compost-soil germination and growth tests were not sensitive enough to detect differences between mature and immature ‘composts’, that other test(s) must be used to evaluate compost maturity.  相似文献   

10.
Abstract

In vitro‐grown Chrysanthemum morifolium Ramat. cultivars Bright Golden Anne, Deep Luv, and Lucido were exposed to elevated mannitol, sucrose, or sorbitol concentrations to see if their response to this osmotic stress mimics that of in vivo plants enduring water deficit. The relative efficacy of the three osmotic agents at manifesting a response was also evaluated. Tissue osmolarity paralleled media mannitol and sorbitol concentration for all three cultivars. Shoot growth correspondingly decreased with increased osmolarity applied during the rooting phase. These responses generally resembled those of water‐stressed greenhouse plants. The degree of response varied with cultivar; ‘Lucido’ was the most sensitive and ‘Bright Golden Anne’ the least. Sucrose (metabolized by the plants) failed to elicit consistent osmotic stress symptoms; instead it enhanced both shoot and root growth. In vitro stress‐induced symptoms were produced in both proliferation and rooting stages, but consistent shoot growth reduction with increasing levels of incorporated osmotic agent was only observed during rooting. Plants did not retain the osmotic adjustment when they were subsequently subcultured from the stress treatments back to the control medium.  相似文献   

11.
Six cultivars of sunflower (Helianthus annuus L.), were screened under controlled environmental conditions for tolerance to Al stress and water stress imposed separately and in combination with one another. Plants were grown for 4 weeks in waxed cartons containing 1 kg of acid, Al‐toxic Tatum, subsoil (clayey, mixed, thermic, Typic Hapludult) at high (pH 4.3) or low (pH 6.3) Al stress. During the final 2 weeks they were also subjected to low (‐20 to ‐40 kPa) or high (‐60 to ‐80 kPa) water stress. Plant growth responses and symptoms of Al toxicity suggested that a wide range of cultivar sensitivity existed. ‘Manchurian’, ‘S‐212’, ‘S‐254’, and ‘S‐265’ were relatively tolerant to Al toxicity while cultlvars ‘Romania HS‐52’ and ‘RM‐52’ were extremely sensitive. Under high Al stress and high water stress, chloroplasts in cells from the Al‐sensitive cultivar ‘Romania HS‐52’ were smaller and contained less starch than chloroplasts from the Al‐tolerant cultivar ‘Manchurian’. Furthermore, the smaller chloroplasts tended to have fewer grana stacks per unit area than did the chloroplasts from tolerant plants. These differences were not apparent when the Al‐sensitive cultivar was grown either in the absence of Al or water stress. In general, Al‐sensitive cultivars of sunflower were more tolerant to water stress than were Al‐tolerant cultivars. Increasing the soil moisture level reduced Al toxicity in Al‐sensitive cultivars. Similarly, decreasing Al stress partially overcame the detrimental effects of high water stress. Hence, Al stress and water stress are interrelated factors which must be considered in the characterization and breeding of plants for better adaptation to acid soils.  相似文献   

12.
模拟干旱和盐碱胁迫对碱蓬、盐地碱蓬种子萌发的影响   总被引：5，自引：3，他引：2  
为研究干旱和盐碱胁迫对碱蓬(Suaeda glauca)、盐地碱蓬(Suaeda salsa)种子萌发的影响,比较碱蓬和盐地碱蓬逆境生理特性的异同,本研究利用PEG6000、NaCl和Na_2CO_3分别模拟干旱、盐和碱胁迫,配制相同渗透势的PEG6000、NaCl、Na_2CO_3处理液,以蒸馏水处理为对照,对碱蓬、盐地碱蓬种子的萌发与胚的生长进行比较研究。结果表明:1)低渗处理(-0.46 MPa)对碱蓬、盐地碱蓬种子的萌发无显著影响;高渗处理(-1.38MPa、-1.84 MPa)抑制碱蓬、盐地碱蓬种子的萌发。2)当溶液渗透势相等时,NaCl处理下碱蓬种子的萌发率显著大于PEG、Na_2CO_3处理;而等渗PEG、NaCl、Na_2CO_3处理对盐地碱蓬种子萌发率的影响无显著差异。3)PEG、NaCl、Na_2CO_3处理组碱蓬、盐地碱蓬种子的最终萌发率与对照无显著差异。4)在幼苗形成阶段,PEG、Na_2CO_3处理对碱蓬、盐地碱蓬胚的抑制作用显著大于等渗NaCl处理。5)碱蓬、盐地碱蓬胚的生长对NaCl、Na_2CO_3胁迫的响应存在差异。-0.92 MPa NaCl处理抑制碱蓬胚的生长,却对盐地碱蓬产生促进作用;-0.46 MPa Na_2CO_3处理对碱蓬胚的抑制作用小于盐地碱蓬。综合分析表明:碱蓬、盐地碱蓬均具有很强的抗盐性。在种子萌发阶段,碱蓬种子的抗旱、抗碱能力低于盐地碱蓬;在幼苗形成阶段,碱蓬胚的抗盐性小于盐地碱蓬,但对轻度碱胁迫的抗性高于盐地碱蓬。  相似文献   

13.
Two indica rice (Oryza sativa L.) cultivars, viz. ‘Swarna’ and ‘Kalinga III’ were compared for their response to iron (Fe) stress. The cultivars were raised with four Fe levels viz. 0.05, 1, 5, 10 mg L?1 in hydroponic culture. Plant growth, soluble protein, chlorophyll content and phytoferritin of leaves increased significantly with increase in Fe concentration up to 5 mg L?1, but decreased at 10 mg L?1. In contrast, lipid peroxidation, decreased up to 5 mg L?1 then increased at 10 mg L?1. However, at 10 mg L?1 of Fe these parameters were more adversely affected in ‘Swarna’ than ‘Kalinga III’. The later also accumulated relatively more Fe, zinc (Zn), manganese (Mn), and copper (Cu) from the growing medium. Zinc concentrations of the tissue, on the other hand, exhibited the opposite trend. Iron stress may, thus lead to secondary metallic ion stresses and under such situations cultivars like ‘Kalinga III’ will perform better than ‘Swarna’.  相似文献   

14.
Primary determinants of crop production in arid/semiarid regions are lack of moisture and infertility, especially phosphorus (P) deficiency or unavailability. The effects of P and water stress (WS) levels on shoot and root dry matter (DM), leaf area, root volume, total root length, and shoot and root P concentrations and contents were determined in two bean [Phaseolus acutifolius Gray, cv ‘Tepary #21’ ("drought‐resistant") and P. vulgaris L., cv “Emerson’ ("drought‐sensitive")] and two sorghum [Sorghum bicolor (L.) Moench, cv SA7078 ("drought‐resistant") and ‘Redlan’ ("drought‐sensitive")] cultivars grown in nutrient solution. Plants were grown with different levels of P (20 and 100 μM for bean and 20, 80, and 160 μM for sorghum) when seedlings were transferred to nutrient solution, and WS levels of 0, 13.8, and 1 6.4% polyethylene glycol (PEG‐8000) introduced after plants had grown in solution 23 days (bean) and 31 days (sorghum). All growth traits were lower when bean and sorghum plants were grown with WS and low P. Growth traits were higher in cultivars grown with high compared to low P regardless of WS. Root P concentration and content and shoot content, but not shoot P concentration, were lower when bean plants were grown with WS compared to without WS. Tepary #21 bean had higher shoot DM, leaf area, total root length, and shoot P concentration than Emerson when plants were grown with WS at each level of P. Sorghum shoot and root P concentrations were higher as P level increased regardless of WS, and WS had little effect on shoot P concentration, but root P concentration was higher. Contents of P were similar for SA7078 and Redlan regardless of P or WS treatment, but SA7078 had greater P contents than Redlan over all P and WS treatments. “Drought‐resistant”; cultivars generally had better growth traits, especially total and specific root lengths, than “drought‐sensitive”; cultivars.  相似文献   

15.
Field studies were conducted to assess boron (B) requirement, critical concentrations in diagnostic parts based on yield response curves and genotypic variation by growing three peanut (Arachis hypogaea L.) cultivars (‘Golden’, ‘BARD-479’, ‘BARI-2000’) on two B-deficient calcareous soils. Boron application significantly increased pod yield of all the cultivars over control. Maximum pod yield increases were: ‘Golden’, 16?23%; ‘BARD-479’, 21?27%; and ‘BARI-2000’, 25?31%. The cultivars varied in B efficiency and cv. ‘Golden’ was the most B efficient (81?86%) while cv. ‘BARI-2000’ was the least efficient (76?80%). Boron requirements for near-maximum (95%) dry pod yield were 0.65 kg ha?1 for ‘Golden’, 0.75 kg ha?1 for BARD-479 and 0.80 kg ha?1 for BARI-2000. Critical B concentrations in shoots and seeds were: ‘Golden’, 33 mg kg?1 and 26 mg kg?1; ‘BARD-479’, 38 mg kg?1 and 31 mg kg?1; and ‘BARI-2000’, 42 mg kg?1 and 33 mg kg?1.  相似文献   

16.
The effects of nickel (Ni) on growth, leaf water status, and mineral nutrient concentration were studied in two wheat (Triticum durum Desf.) cultivars with different sensitivity to water stress: ‘Adamello’ [drought sensitive (DS)] and ‘Ofanto’ [drought tolerant, (DT)]. The DT cultivar showed a higher Ni absorption capacity: ‘Ofanto’ seedlings grown in the presence of 35 μM Ni had a 3.5 times greater concentration of Ni in roots than did ‘Adamello’. Despite the greater Ni tissue content, the DT cultivar exhibited better growth and nutritional status when compared to the DS cultivar. In the DS cultivar the concentration of chlorophyll a and b was reduced by Ni treatment. Chlorophyll a concentration decreased in the DT cultivar, but to a lesser extent than in the DS cultivar; chlorophyll b was not altered by Ni level in the DT cultivar. Nickel caused a decrease in the water potential (ψw) and relative water content (RWC) in both cultivars, but these decreases were greater in the DS cultivar. The antioxidative defense enzymes, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase, showed increased activity in Ni‐treated DS seedlings; this increase in activity was not observed in the DT seedlings. These data suggest that different wheat genotypes may markedly differ in Ni uptake and sensitivity and that a enhanced capacity to counteract Ni stress may be associated with drought resistance.  相似文献   

17.
Some Kentucky bluegrass (KBG; Poa pratensis L.) is susceptible to iron (Fe)-deficiency chlorosis. Under Fe-deficiency stress, phytosiderophore is produced and released by the roots of many grasses to solubilize soil Fe and enhance uptake. In other species, quantifying phytosiderophore screens for Fe-deficiency resistant cultivars. A hydroponic study was conducted at 1 and 10 μM solution Fe to variously stress ‘Baron’, ‘Award’, ‘Limousine’, and ‘Rugby II’ KBG cultivars. One μM Fe solution produced more Fe-deficiency stress in all cultivars compared to 10 μM, resulting in greater chlorosis and phytosiderophore release but reduced shoot and root Fe concentrations and shoot weight. Of the four cultivars, Baron was the most susceptible to Fe deficiency and exhibited severe Fe chlorosis and low shoot Fe but, surprisingly, produced the most phytosiderophore. These results imply that Fe-deficiency susceptibility in KBG may be less related to phytosiderophore release and more related to inefficient uptake or utilization mechanisms.  相似文献   

18.
Abstract

The effects of rice straw and alligator weed (Alternanthera philoxeroides) residue on germination of selected rice cultivars grown in Louisiana were studied. Germination was influenced by both plant residue source and application rate. Alligator weed, which caused a rapid decrease in soil redox and pH, had a greater impact on germination than rice straw addition. There were distinct differences in rice cultivars ‘response’ to plant residue application rate and source. Alligator weed showed significant germination inhibition for all cultivars tested as compared to rice straw.  相似文献   

19.
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   

20.
The effect of nitrogen (N) application rate and sowing date on seed quality and pod production of four cultivars of okra (Abelmoschus esculentus L.) were examined. Seeds of four okra cultivars (cv. ‘Boyatiou’, ‘Veloudo’, ‘Clemson’, and ‘Pylaias’) were sown on 13 May (1st sowing) and 2 June (2nd sowing). Plants were subjected to three N levels: F1, F2, and F3 (150, 300, and 450 mg N L?1). The 2nd sowing improved flower induction and pod set, without however affecting pod size. The number of seeds per pod was not affected by sowing time, but the mean 100 seed weight was generally lower in the 2nd sowing. In all cultivars, except cv. ‘Veloudo’ germination increased in the 2nd sowing mainly as a result of lower seed hardness. Germination was also improved by increasing N levels, or by seed storage, acid scarification, or seed priming.  相似文献   

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