首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 29 毫秒
1.
Soil contains water and nutrients necessary for the development of cultivated plants and serves as a substrate and support in terrestrial ecosystems. For reasons inherent to the nature of soil, salt content can considerably limit the growth of plants. With the implementation of salinity-tolerant crops, saline soils can be transformed into productive and sustainable areas. In Tunja, Colombia, a trial was developed to quantify the changes in growth, water intake, fiber, nitrogen and chlorophyll content in Furcraea hexapetala plants exposed to NaCl saline conditions. Plantlets obtained from bulbs were grown in an aerated nutrient solution under greenhouse conditions. Measurements of 30, 60 or 90?mmol NaCl was added to the nutrient solution and control plants were left without addition of salt. As a consequence of salinity, leaf area, leaf area ratio, water uptake, absolute growth rate, relative growth rate, fiber content, dry matter, chlorophyll and nitrogen content in leaves were reduced. The accumulation of dry matter in leaves, stem and roots was especially affected when the plants were exposed to 90?mmol of NaCl. Accumulated dry matter increased in the stems, but reduced in the leaves. These results suggest that plants of Furcraea hexapetala can tolerate up to 60?mmol of NaCl (4.9?dS?m?1) without substantially affecting the parameters that determine the growth or the fiber content in the leaves.  相似文献   

2.
Throughout the development of plants, certain biotic and abiotic phenomena can occur which reduce not only the photosynthetic area, but also the growth, depending on the stage of plant development. Responses by plants to defoliation depend on species, the timing of agricultural practices and the intensity level of defoliation. An experiment was carried out in Tunja, Colombia under greenhouse conditions, in order to evaluate the tolerance of faba bean plants (Vicia faba) to partial defoliation. Every week material was removed along each newly emerged leaflet to simulate 50% defoliation. Another group was grown with the entire leaf area to function as a control. As a result of partial defoliation, the specific leaf area, absolute growth rate, relative growth rate and total biomass were reduced, but the leaf weight ratio was increased. In addition, the pattern of dry matter partitioning was altered so that the amount of biomass accumulated was reduced in the roots, but increased in the leaves. Additionally, the partially defoliated plants showed the ability to partly restore the removed leaf area. In this way it could be inferred that the plants of Vicia faba present a moderate capacity to tolerate early defoliation during the vegetative phase.  相似文献   

3.
Excess iron in soils affects many agricultural areas worldwide, causing great losses in cultivated plants particularly in waterlogged environments. Plants, such as the calla lily (Zantedeschia aethiopica), which grows in such wetlands, have been widely used for the treatment of wastewater. White calla lily plants were grown hydroponically from seeds in a greenhouse in Tunja, Colombia, under either of three different levels of iron (0, 100 or 200 ppm Fe) to evaluate the plant’s tolerance to excess iron. The total dry mass production, water uptake, water use efficiency (WUE), dry matter partitioning and root to shoot ratio were recorded four months after transplanting. The dry mass production per plant decreased as the iron level increased. Although water uptake decreased inversely proportional to the iron level, the WUE was not affected by iron. On the other hand, iron affected dry matter partitioning to the plant organs, accumulating more dry matter in the roots than in the shoot with higher iron levels. Hence, we suggest that the calla plant is moderately tolerant to excess iron and would be appropriate for the phytoremediation of wetlands contaminated with this metal.  相似文献   

4.
About 900.000 ha of Egypt’s agricultural lands are suffering from salinity build-up problem. Therefore, two field experiments were conducted in split-split plot design with four replications to study α?tocopherols foliar application with 100 and 200 ppm and hand hoeing (two and three hand hoeing, plus unweeded) and their interactive effects on growth, osmoprotectants, mineral contents, seed yield, yield components, and nutritive value of the lupine plants and its associated weeds grown under salt-affected soil at 1.30, 3.20 and 4.23 dS m?1. Three hand hoeing treatment achieved the highest weed depression expressed in the lowest number and dry matter of broad-leaved, narrow-leaved and total weeds, and reduction % in dry matter were 80.75, 78.25 and 79.26 % compared with unweeded, respectively. Salinity stress significantly decreased total chlorophyll content, leaf area index and plant dry weight, while α?tocopherol and hoeing increased in all previous traits relative to corresponding controls. Lupine seed yield, yield components, and oils, carbohydrates, proteins, carotenoids and alkaloids in the yielded seeds were significantly reduced by increasing salinity levels, meanwhile hoeing and α?tocopherol treatments improved them. Total essential amino acids were decreased by increasing salinity levels and increased by increasing α?tocopherol concentrations and number of hoeing treatments. It could be concluded that α?tocopherol especially at 200 ppm partially alleviated the harmful effects of salinity stress on the growth of lupine plants and nutritive value of the yielded seeds. Three hand hoeing treatment was the optimum and safe method in controlling weeds associated with lupine plant grown under salinity stress.  相似文献   

5.
Photosynthesis is an important process for plants in which plants utilize the energy from sunlight to manufacture and produce all their own food. Although UV-C damage is not physiologically relevant for plants growing in the sun, short-wavelength (UV-C) radiation from germicidal lamps has been used to study cell damage in animals as well as in plants. This study provides a review of the effects of a methanolic extract of spinach (SE) as a natural powerful antioxidants used at two concentrations (25 and 50?ppm) on fenugreek seedlings grown under UV-C stress conditions. The results revealed that exposure of fenugreek seedlings to low UV-C period (30?min) increased growth criteria of the produced seedlings. In addition, the contents of chlorophyll, total pigments, total protein, free amino acids, non-enzymatic (carotenoids, total phenol, flavonoids, α?tocopherol & ascorbic acid contents) and enzymatic antioxidants were increased at this period. By increasing exposure periods of UV-C radiation, the growth criteria and chemical constitutes of the seedlings were decreased. Application of lower concentration of SE (25?ppm) improve the growth of the seedlings at 30-min UV-C and was able to protect seedlings from high periods of UV-C irradiation by increasing all measured parameters except CAT. These increases might be an adaptive mechanism to minimize the adverse effects of longer exposure of UV-C radiation. Moreover, treating the irradiated seedlings with spinach extract led to an obvious alteration in gene expression including synthesis of some proteins bands and disappearance of other protein sets of the protein profile.  相似文献   

6.
Maize production trials carried out in eastern middle of Germany from 1999–2008 were used for statistical analysis of the optimum date for silage maize ripeness. The Knowledge about difference in ripeness between grain and residual plants at the harvest were used for exactly choice of cultivar under drought conditions for silage and energy maize. The Silage maize Ripeness Index (the ratio of dry matter content of maize grains to dry matter content of residual plants) is more suitable for the leading of plant development, the determination of harvest date and the choice of cultivar as the dry matter content of the plant. The analysis is cheaper as well as not so material and time-consuming with a better financially results in food-, milk- and methane production in comparison to the dry matter content of the silage maize of different hybrid maize populations and environments. Ensilage optimum and yield maximum correspond with the physiological ripeness of silage maize and are close to the grain dry matter content of 64%, to the dry matter content of starch of 33% and a ripeness index from 2.55 to 2.9 for parameter of quality and quantity. Only under these conditions it is possible to reach the optimal ripeness of 33 to 35% in the whole plant silage maize. But under suboptimal conditions the harvest is carried out, if SRI had a maximal value. In dependence on the Silage maize Ripeness Index (SRZ) and (SRI) parameters of silage and energy maize were predicted differential development of ripeness and yield. The aims of silage and energy maize are similar. The Silage maize Ripeness Index (SRI) is, for whole plant maize, better than the Whole Plant Maize Ripeness Index (SRZ) for the choice of a hybrid in Germany. The dry matter content of grain in interaction with the dry matter of residual plants are better than dry matter content of the whole plant maize as ripeness indicator in the production of silage and energy maize at the harvesting time. SRI is also universal suitable for use as a standard in scientific trials and for better characteristic of cultivar types and environmental influence.  相似文献   

7.
Maize production trials carried out in the middle of eastern Germany from 1999–2005 and were used for statistical analysis of the optimum date for silage maize ripeness. The Silage maize Ripeness Index (SRI, the ratio of dry matter content of maize grains to dry matter content of stover) is more suitable for the determination of harvest date, yield maximum and silage maize quality as the dry matter content of the plant. The analysis is cheaper and less material and time-consuming in comparison to the dry matter content of the silage maize of different hybrid maize populations and environments. Ensilage optimum and yield maximum correspond almost with the physiological ripeness of silage maize and are close to the grain dry matter content of 60–65%, to the dry matter content of stover under 24% and a ripeness index from 2.5 and higher. Recently, the silage maize harvest depends on dry matter content of maize plants (30–35%). This can result in grain ripening rates less than 55% and low starch as well as energy contents. The dry matter content of the silage maize is at a certain ripeness of grain and/or of starch only expression of aging of the stover. When the stover has a stronger influence as the grain on the dry matter content of the whole plant maize, than the crop should be harvested before reaching the optimum of ripeness and yield maximum. Therefore only hybrids with a long harvesting time, high starch storage and displaying a high digestibility of plant cell wall with slow drying of the stover should be grown in the future. The Silage maize Ripeness Index is, for whole plant maize, better than the Whole Plant Maize Ripeness Index (SRZ) for the choice of a hybrid in Germany. The dry matter content of grain in interaction with the dry matter of stover are better than dry matter content of the whole plant maize as ripeness indicator in the production of maize for the harvesting time. SRI is also suitable for use as a standard in scientific trials and for better type-characteristic of varieties.  相似文献   

8.
Maize production trials carried out in Germany from 1999–2004 were used for statistical analysis of the optimum date for silage maize ripeness. The Silage maize Ripeness Index (the ratio of dry matter content of maize grains to dry matter content of stover) is more suitable for the determination of harvest date, yield maximum and silage maize quality as the dry matter content of the plant. The analysis is cheaper as well as less material and time-consuming in comparison to the dry matter content of the silage maize of different hybrid maize populations and environments. Ensilage optimum and yield maximum almost correspond to the physiological ripeness of silage maize and are close to the grain dry matter content of 60–65%, to the dry matter content of stover under 24% and a ripeness index from 2.5 and higher. Recently, the silage maize harvest depends on dry matter content of maize plants. This can result in grain ripening rates less than 55 % and low starch as well as energy contents. The dry matter content of the silage maize is at a certain ripeness of grain and/or of starch only expression of aging of the stover. The stover has, together with the grain, a strong influence on the dry matter content of the whole plant maize. On these locations the crop should be harvested before reaching the optimum of ripeness and yield maximum. Therefore only hybrids with a long harvesting time, high starch storage and displaying a high digestibility of plant cell wall with slow drying of the stover, should be grown in the future. The Silage maize Ripeness Index (SRI) is, for whole plant maize, better than the Whole Plant Maize Ripeness Index (SRZ) for the choice of a hybrid in Germany. The dry matter content of grain in interaction with the dry matter of stover are better than dry matter content of the whole plant maize as ripeness indicator in the production of maize. SRI is also suitable for use in scientific trials as a standard for the harvesting time and for better “stay green” characteristic. It is a strong correlation between the Silage maize Ripeness Index (SRI) and Silage maize Nutrient Index (SNI) or Silage maize Quality Index (SQI), respectively, as indicator for the physiological reaction of starch and metabolised energy in the rumen as well as for the choice of a hybrid.  相似文献   

9.
Reducing destructive effects of lettuce plants irrigated with saline water was investigated in two field experiments conducted at Ismailia Governorate in 2012–2013 and 2013–2014. Two lettuce (Lactuca sativa L.) cultivars, Great Lakes and Balady, irrigated with saline water (3.22 dS/m) were treated using two levels of salicylic acid (SA) and glycine betaine (GB) as a foliar application (200, 400 ppm and 15, 30 Mm, respectively). Generally, application of SA and GB enhanced growth parameters, i.?e. plant height; root length; number of leaves per plant; plant fresh and dry weight; leaf relative water content (LRWC); membrane permeability (MP); lipid peroxidation (MDA); chlorophyll a, b and carotenoid content in leaf; proline; total soluble sugars (TSS); superoxide dismutase (SOD) and peroxidase (POD) activity; and Na, K, Ca content. GB treatments significantly increased most recorded growth parameters, especially at 30 mM, while this treatment decreased values of MP, (MDA) and Na content in two lettuce cultivars.  相似文献   

10.
Iron (Fe) and zinc (Zn) are essential nutrients for plant growth and development. Therefore, a pot experiment was conducted to examine the role of Zn and Fe on vegetative growth, photosynthetic pigments, soluble sugars, soluble protein, nitrate reductase (NR), ascorbate peroxidase (APX), catalase (CAT), minerals content, amino acid composition fraction, isozymes, and protein electrophoresis in faba bean plants foliar sprayed with FeSO4 and ZnSO4. The results revealed that foliar spray with 1 or 3 g/L of FeSO4 and ZnSO4 significantly increased all the abovementioned parameters compared to control plants. The activity of esterase increased with increasing concentration of Fe and Zn as compared to control plants. The most pronounced increase was found in plants treated with 3 g/L ZnSO4. Three bands of peroxidase isozyme were exhibited with different densities and intensities in all treatments. Three types of modification were observed in the protein patterns of faba bean leaves. Some protein bands disappeared, while other increased and synthesis of a new set of proteins was induced. It could be concluded that foliar spray with the two concentrations (1 or 3 g/L) of ZnSO4 and FeSO4 helped faba bean plants to overcome the deficiency in these minerals by producing antioxidant enzymes. Improved faba bean growth through adequate Fe and Zn foliar spray is likely a promising strategy to improve Vicia faba plants.  相似文献   

11.
In this investigation, leaf extracts of Ocimum basilicum and Mangifira indica were used as reducing agents for biosynthesis of silver nanoparticles (AgNPs). The biosynthesized AgNPs were authorized by UV-vis spectrophotometry and X?ray diffraction (XRD) analysis. AgNPs were obtained after 5?min of reaction at 80oC. The formation of AgNPs was confirmed by the presence of absorption peaks at 439?nm using extract from O. basilicum and at 442.5?nm from M. indica. X?ray spectra showed strong peaks for the crystalline Ag. Shape and size of the biosynthesized AgNPs were studied using high resolution transmission electron microscope (HR-TEM). Size of the produced AgNPs was found to be 9–35?nm. Effect of the synthesized nanosilver was then investigated on some biochemical attributes of wheat plant (Triticum aestivum cultivar saka 92). The growth parameters such as shoot lengths, fresh and dry weight of shoot, chlorophyll, carbohydrate and protein contents in shoot of wheat plant were investigated. Application of AgNPs synthesized from Ocimum basilicum and from Mangifira indica at the concentrations of 20,40?ppm showed an increase in shoot length, fresh and dry weight of shoot, chlorophyll, total carbohydrate and protein content in shoot of wheat plants, beyond these concentrations an inhibitory effects were shown.  相似文献   

12.
Nowadays, only little information regarding the climber Clitoria ternatea L. var. pleniflora Fantz as “new ornamental plant” does exist in the German-speaking area. This plant is from interest because of its characteristic attractive, bright blue flowers. The vegetative propagation of Clitoria ternatea was investigated at the Institute for Horticultural Sciences, Humboldt-University of Berlin. The objective was to study how different types of cuttings could influence the rooting, proliferation and growth behaviour of greenhouse plants cultivated in two different seasons (summer and autumn). It was found that either stem or tip cuttings from the lower and middle zones of the mother plants with a fully developed leaf are suitable for summer or autumn propagation. Also, it was shown that the cutting variants affected the branching behaviour and further plant growth. Nearly 90% of the trial plants remained with a single shoot. However, in the vegetation period 11% of the plants originating from tip cutting and 14% of the plants originating from stem cuttings could be found with two branches. In autumn, the formation of lateral shoots was strongly declining. Here, the shoot length was particularly influenced by using different types of cutting treatments during propagation. The stem cuttings of the first batch planted clearly developed plants with longer shoots compared to those growing from tip cuttings. In the second batch planted, a lower shoot length growth was generally recorded (means of 5 to 6?cm for the internodes after three-month cultivation). In conclusion, the results regarding the propagation show that C.?ternatea can be recommended as a new ornamental container plant. However, further studies should follow in order to investigate possible photoperiod effects as well as suitable cultivation measures.  相似文献   

13.
In order to determine the effect of two bio-stimulants under NPK fertilizer rates on growth and nutrient content and yield of zucchini (squash), an experiment was conducted at Mendel university during 2014. The treatments included four NPK rates namely, 0, 75, 100 and 150% of recommended rate in combination with foliar application of Pentakeep super and strigolactones (alone and in combination) were used. This study was arranged in a split plot design in three replications. The results showed NPK at 150% led to the maximum significant increase of growth characters i.?e., leaf number, fresh and dry weight of leaves relative to unfertilized control. Chlorophyll reading increased significantly with increase in NPK supply up to NPK75%. The highest contents of N, K and nitrate were found in zucchini leaves treated with NPK at 150% of recommended rate. Yield and its component increased significantly with increase in NPK supply up to 100% of recommended rate. The combined application of Pentakeep super and strigolactones significantly maximized growth characters and fruit yield as compared to control treatment. The highest content of N generated in plants sprayed with Pentakeep super while application of Pentakeep and strigolactones did not affect the P and K contents. Whereas, control plants effectively significantly increased the chlorophyll and nitrate content of leaves.  相似文献   

14.

Abiotic stress has a negative impact on plant physiology, influencing the overall growth and development of plant crops. Saline stress is one of the most serious environmental issues limiting crop plant production. Biofertilizers are reparative elements used in soil to increase tolerance to salinity and drought stress. We investigated the effect of salinity stress on qualitative and quantitative characteristics of cherry tomato plants (Lycopersicon esculentum cerasiforme) with biofertilizer application 0, 15 and 30 days after transplanting in this study. After different days of transplantation, different levels of salinity (0, 50, 100, and 150?mM) were used with biofertilizer (Azospirillum sp. and Azotobacter sp.) application (0, 15 and 30 days). The salinity (150?mM NaCl) significantly affected the studied variables, which were recorded with minimum levels of leaf area (52.42?cm2), root length (6.54?cm), fresh root weight (13.64?g), yield (6.52 tons/ha), leaf chlorophyll content (36.11?mg/m2) and maximum levels of total soluble solids (TSS, 8.87 °Brix). Control samples had higher leaf area (58.35?cm2), root length (15.23?cm), fresh root weight (17.86?g), yield (9.39 tons/ha), leaf chlorophyll content (44.09?mg/m2), and lower TSS (7.93 °Brix). Plants that received biofertilizer (15 days after transplanting) had higher plant height (73.41?cm), stem diameter (0.74?cm), leaf area (61.16?cm2), root length (15.35?cm), fresh root weight (18.38?g), root dry matter (60.41%), yield (10.43?t/ha), leaf chlorophyll content (42.55?mg/m2), fruit dry matter content (10.12?g), pH 4.52, and TSS (9.30 °Brix). The minimum plant height (51.33?cm), stem diameter (0.55?cm), leaf area (49.60?cm2), root length (7.04?cm), fresh root weight (12.76?g), root dry matter (42.16?g), yield (5.15 tons/ha), leaf chlorophyll content (35.18?mg/m2), fruit dry matter content (6.59?g), pH 4.27 and TSS (7.55 °Brix) were recorded in plants with no application of biofertilizer. The present study revealed that most growth and quality variables were negatively affected by salinity except for TSS, which showed positive effect with application of 150?mM of NaCl. Biofertilizer application at 15 days significantly influences the quantitative and qualitative attributes of cherry tomato under different levels of salinity.

  相似文献   

15.
V. G. BREEZE 《Weed Research》1988,28(4):297-301
Four-week-old tomato plants were exposed to fluroxypyr vapour at four concentrations between 0?37 pg l?1 and 5?5 pg l?1 for 48 h. Leaf epinasty and stem elongation were observed during this period and the rate of net CO2 exchange in the light by the plants exposed to the highest vapour concentration also began to decline. Visible symptoms of phytotoxicity were present on all treated plants 4 weeks after exposure, indicating that assimilation of fluroxypyr vapour had taken place at concentrations as low as 0?37 pg l?1. Only the plants exposed to 5?5 pg l?1 had reduced shoot dry weights but the others were generally taller and had lower dry matter contents, compared with untreated plants.  相似文献   

16.
Tan spot caused by Pyrenophora tritici-repentis is the main foliar diseases of wheat in Brazil. The effect of silicon (Si) on the components of resistance of a susceptible (Fundacep Horizonte) and a moderately resistant (Quartzo) wheat cultivar was studied in a controlled environment. Silicon was supplied as calcium silicate in the soil 30 days before sowing. At the booting stage, a conidial suspension of the fungus was sprayed onto the flag leaves of potted plants, which were incubated under moist conditions for 48 h. Afterwards, inoculated leaves were assessed for: incubation period (IP), infection efficiency (IE), area under lesion size curve (AULSC), lesion size (LS), severity (SEV) and area under severity curve (AUSC). Foliar Si concentrations were quantified at the end of the evaluations. Si supply to plants increased leaf Si concentration in 233% for Fundacep Horizonte (from 4.8 to 16.0 g kg?1 of dry matter) and 211% for Quartzo (from 5.3 to 16.5 g kg?1 of dry matter). In the Si + treatments, IP was longer by 24 and 17 h, IE declined by 53.5 and 65.5%, LS (at 264 h after inoculation) by 4.6 mm (from 9.5 to 4.9 mm) and 5.9 mm (from 8.2 to 2.3 mm), and SEV by 53% (from 54.4 to 18.8%) and 88% (from 47.7 to 5.5%) respectively, for the Fundacep Horizonte and Quartzo cultivars. The Si x cultivar interaction was not significant for AULSC and AUSC, and these variables were reduced by 55.8 and 80.8%, respectively, in plants supplied with Si. In conclusion, Si enhanced the resistance of wheat plants to tan spot development by affecting several resistance components, regardless of the resistance level of the cultivar. However, the greatest reduction in tan spot development by Si supply was observed when using a moderately resistant cultivar.  相似文献   

17.
The leaf spot complex constitutes an increasing challenge for integrated pest control in barley. The complex consists of biotic and abiotic factors causing early ripening after a rapid loss of green leaf area, in particular in upper, exposed leaves. Severe symptoms appear late in the growing season after heading. The experience from recent years shows that the control of the leaf spot complex improves yield. Best control is achieved by new, effective fungicides. Efficiency is improved by late fungicide application and is dose-dependent. In contrast, late treatments provide poor control of early appearing diseases. For a successful disease control in barley good efficiency in the control of the leaf spot complex appears based on a sufficient control of the other diseases. For optimization of disease control, we require improved knowledge of the epidemics of the leaf spot complex and of the contribution of individual biotic and abiotic factors. Besides the weather, the fungal pathogen Ramularia collo-cygni and its photodynamic toxins play a mayor role in symptom development. By combination of conventional and molecular diagnostics we aim at a better understanding of the complex as a basis for early and reliable prediction of epidemics. Because non fungicidal factors like the physiological plant age play a significant role in the occurrence of the leaf spot complex, they should be taken into account for integrated control.  相似文献   

18.
Plants of four potato (Solanum tuberosum L.) cultivars were grown in pots in a greenhouse at five densities ofGlobodera pallida between 0 and 300 eggs per gram of soil. Photosynthesis and transpiration of selected leaves were measured at 30, 37, 49 and 60 days after planting. Stem length was recorded at weekly intervals. Plants were harvested 70 days afteer planting and various plant variables were determined.At 30 days after planting, when second and third stage juveniles were present in roots, both photosynthesis and transpiration rates were severely reduced byG. pallida. In the course of time these effects became less pronounced. Water use efficiency was reduced byG. pallida between 30 and 49 days, but not at 60 days after planting. The results suggest independent effects ofG. pallida on stomatal opening and on photosynthesis reactions. There were no consistent differences among cultivars in the response of leaf gas exchange rates and water use efficiency to nematode infection. Reduction of photosynthesis byG. pallida appeared additive to photosynthesis reduction due to leaf senescence.Total dry weight was reduced by 60% at the highestG. pallida density. Weights of all plant organs were about proportionally affected. Shoot/root ratio was not affected and dry matter content was reduced. Stem length and leaf area were most strongly reduced during early stages of plant-nematode interaction. The number of leaves formed was only slightly reduced byG. pallida, but flowering was delayed or inhibited. Reduction of total dry weight correlated with reduction of both leaf area and photosynthesis rate. Leaf area reduction seems the main cause of reduction of dry matter production. Tolerance differences among cultivars were evident at 100 eggs per gram of soil only, where total dry weight of the intolerant partially resistant cv. Darwina was lower than that of the tolerant partially resistant cv. Elles and of the tolerant susceptible cv. Multa. The tolerance differences were not correlated with leaf photosynthesis and transpiration. Apparently these processes are not part of tolerance of plants.  相似文献   

19.

Vegetables in the tropics are grown continuously throughout the year due to the favorable climate. Unfortunately, leafy vegetables are often damaged because of slugs and snails. These mollusks and other herbivores cause different levels of defoliation to plants which can significantly impact their growth, production, and quality of the harvested product. A study was carried out in order to artificially simulate the effect of a loss in foliar area caused by these pests. The impact of severe artificial defoliation in spinach plants (Spinacia oleracea) was evaluated in Tunja, Colombia. Under greenhouse conditions and after transplanting, the plants had 75% of their leaf area removed. This procedure was repeated weekly on newly emerging leaves while a control group of plants was left intact. 71 days after transplanting, the plants were harvested, and the leaf area and dry weight of the plants were measured with which some allometric variables were calculated to express growth. Variables such as the number of leaves, plant height, total dry weight, relative growth ratio, leaf weight ratio (LWR), and root to shoot ratio (R:S) were unaffected by defoliation while leaf area, leaf area ratio (LAR), and specific leaf area (SLA) were reduced with the partial removal of the leaf area. The partial defoliation resulted in an increased partial biomass of the leaves. These results suggest that spinach plants have a moderate tolerance to partial defoliation.

  相似文献   

20.
黄淮海地区夏玉米对干旱和涝渍的生理生态反应   总被引：7，自引：0，他引：7  
利用黄淮海地区多站点的夏玉米水分控制试验,探讨旱涝对夏玉米发育进程、光合能力、干物质分配、叶面积扩展、产量结构及最终产量的影响,进而分析旱涝对夏玉米生长过程的影响机制。结果表明:干旱减缓了夏玉米营养生长阶段的发育速率,但加快了生殖生长阶段的发育进程,而涝渍对夏玉米发育进程的影响较小;夏玉米全生育期土壤湿度距适宜湿度减小1%,其叶片最大光合速率将下降0.3 mol·m~(-2)·s~(-1),比叶面积上升8×10-6hm~2·kg~(-1);夏玉米全生育期土壤相对湿度下降1%,其地上总干重和穗干重均下降0.55%,而产量将减少155kg·hm~(-2);干旱不仅使玉米灌浆时间变短,而且使叶片光合能力下降;营养生长阶段干旱使干物质更多地分配向茎秆,导致叶面积扩展乏力,生殖生长阶段干旱减少干物质向贮存器官的分配而影响产量构成;尽管干旱使叶片变薄而促进其扩展,但仍不足以减缓干旱的整体负面影响,最终导致玉米减产;而涝渍主要使玉米叶片光合能力下降,并导致干物质向穗的分配减少而减产。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号