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1.
L. JONES 《Grass and Forage Science》1991,46(2):153-158
The potential drying rate of cut forage grasses and legumes, following treatment with a 2% potassium carbonate (K2 CO3 ) solution, were compared with those of untreated crops under laboratory conditions. Material was fully exposed to a flow of conditioned air (20°C; 50% relative humidity). Treatment with K2 CO3 had little effect on the drying rate of a range of cultivated grass species. The drying of legume species, particularly lucerne was accelerated. The average reduction in lucerne drying time, following K2 CO3 treatment, was 63% and was similar for a range of varieties. The differential drying of lucerne leaf and stem fractions was reduced following treatment, and reduced further by selective treatment of the stem. Potassium carbonate treatment was superior to traditional mechanical conditioning for accelerating water loss from cut lucerne. The practical implications are discussed. 相似文献
2.
Plant-plant interactions are known as the main biotic drivers of the vegetation dynamics. Therefore, understanding such processes is beneficial for the applied vegetation management. The aim of this research was to investigate the type and intensity of plant-plant interaction during the time course of a growth season. We studied ecophysiological aspects of facilitation and competition between two aridland shrubs, A. meschedensis Bunge and A. raddeanam Czernjak and one perennial grass, B. kopetdaghensis Krasch. Soil and plant sampling were carried out for shrubs and the grass that were either growing alone or the grass was growing under the canopy of shrubs. In Spring (May), soil humidity weight was higher under the shrubs+grass than the grass-only site. By the beginning of Summer (July) grass consumed the common soil water and rapidly terminated its yearly growth. Therefore, in August and September, soil humidity weight was lower under the shrubs+grass than shrub-only sites. Photosynthesis rate of B. kopetdaghensis was sharply reduced from the beginning towards the end of growth season, but was not varied between the different plant combinations. Leaf proline measurement in July indicated higher stress for B. kopetdaghensis that were growing under shrubs than those of open areas. In conclusion, we found facilitation effects of shrubs on the grass at the early times of growth season, but it shifted into the competition for water during summer times. The outcome of plant interaction was positive for the grass but negative for the shrubs, especially A. meschedensis. 相似文献
3.
Seven species or varieties of grass, and a mixture of 3 of them, were sown in pure swards, treated with 4 levels of nitro-chalk (0, 17·5, 35, and 70 Ib N/ac/cut) and cut 4 or 5 times each year. Each species and the mixture were also sown with white clover, and the effect of fertilizer N on the yield of N in each grass was compared with the effect of clover on the yield of N harvested from the grass/clover swards.
The regression line for response in yield of N with increasing levels of fertilizer N showed slight, but significant, upward curvature. The grasses differed in their uptake of N from the soil, S37 cocksfoot and S48 timothy showing relatively high uptakes, and the ability of each grass to take up fertilizer N was usually related to its uptake of N from the soil. Differences in the yield of dry matter between the species, at a similar level of N, are discussed, and it was concluded that perennial ryegrasses were most efficient and Agrostis tenuis was least efficient in using the N taken up in the production of DM.
In general, there were no significant differences between the yields of N of the grass/clover mixtures; the N yields of the grass components were significantly different and tended to be inversely related to the N yields of clover.
Grasses which gave high yields of N with fertilizer were also high yielding when grown in association with clover. Pure grass swards required more than 200 Ib fertilizer N/ac/yr in order to yield the same amount of N as the grass/clover swards. The amount of N estimated to have been derived by grass from clover (indirect effect of clover) increased each year; it was highest with S37 cocksfoot and lowest with Irish perennial ryegrass, averaging 46 and 23 Ib N/ac/yr, respectively. 相似文献
The regression line for response in yield of N with increasing levels of fertilizer N showed slight, but significant, upward curvature. The grasses differed in their uptake of N from the soil, S37 cocksfoot and S48 timothy showing relatively high uptakes, and the ability of each grass to take up fertilizer N was usually related to its uptake of N from the soil. Differences in the yield of dry matter between the species, at a similar level of N, are discussed, and it was concluded that perennial ryegrasses were most efficient and Agrostis tenuis was least efficient in using the N taken up in the production of DM.
In general, there were no significant differences between the yields of N of the grass/clover mixtures; the N yields of the grass components were significantly different and tended to be inversely related to the N yields of clover.
Grasses which gave high yields of N with fertilizer were also high yielding when grown in association with clover. Pure grass swards required more than 200 Ib fertilizer N/ac/yr in order to yield the same amount of N as the grass/clover swards. The amount of N estimated to have been derived by grass from clover (indirect effect of clover) increased each year; it was highest with S37 cocksfoot and lowest with Irish perennial ryegrass, averaging 46 and 23 Ib N/ac/yr, respectively. 相似文献
4.
选用5种常用草坪草（天堂草419、兰引3号、假俭草、中华结缕草和海滨雀稗）进行充分和限制灌水的盆栽试验,通过测定各草坪草蒸散量的变化,得出草坪草在一个生长季内的耗水量及其需水规律。结果表明：（1）长沙地区供试草坪草的水分蒸散主要集中在6～9月,特别是7月和8月的蒸散量最大,充分灌水条件下的蒸散量显著高于限制灌水处理;（2）不同草坪草6～10月的蒸散量不同,天堂草419为931．740～773．502mm,兰引3号为1023．540843．811mm,假俭草为951．461～800．247mm,中华结缕草为1028．889～831．557mm,海滨雀稗为1150．144～937．968mm,在限制和充分灌水条件下,蒸散量的排列顺序均为海滨雀稗〉兰引3号〉中华结缕草〉假俭草〉天堂草419;（3）1d中海滨雀稗蒸散量变化曲线呈单峰型,其余4种供试坪草呈双峰型,1d内蒸散量主要集中在11：00～15：00之间。 相似文献
5.
北方大豆种质引种南方后种子皱缩的研究 总被引：1，自引：0，他引：1
利用６个大豆种持研究不同水分散失速度下，由来热带－热带高温所致皱缩型大豆处子表现的差异，通过本次研究以及往的观察，我们发现原产北方地区地大豆种质，在黄淮大豆生态区及其以南种植，普遍产生皱缩型种子而失去活力，因而在黄淮以南很难保存原产上述地区的大豆种质，限制了地大豆优良基因源的开发和利用。通常情况下，品种间的皱缩粒率有很在差异，变幅在７．４６％－８８．６８％之间，若在生理成熟期加快水分散失速率，则这 相似文献
6.
Sebastian Wojciech Przemieniecki Marta Damszel Tomasz Pawe&#x; Kurowski J&#x;drzej Mastalerz Karol Kotlarz 《Grass and Forage Science》2019,74(1):42-52
Non‐systemic endophytes coexist with grasses and produce positive or negative effects for the host. In agricultural grasses, endophytes such as Epichloë spp. (formerly: Neotyphodium spp.) enhance the biometric parameters and agricultural value of grass biomass and seeds. Some endophytic fungi produce active substances that exert a negative influence on grass‐fed livestock. There is a general scarcity of studies investigating other endophytic fungi, the species composition of fungal communities, fungal species capable of colonizing different grasses and endophyte transfer between grass taxa. This study aims to fill in the existing knowledge gap by describing the relationships between fungal species and grass species. Timothy grass (Phleum pratense L.) is more readily colonized by endophytic fungi than perennial ryegrass (Lolium perenne L.), and the ratio of fungi isolated from the above species was determined at 3:1. Ecological indicators, especially diversity, were also higher in the fungal community colonizing timothy grass. The vast majority of the isolated fungi were ascomycetes. In addition, two Basidiomycota isolates and three Oomycota isolates (Phythium acanthicum) were also obtained from timothy grass. The most prevalent fungal species were Alternaria alternata, Microdochium bolleyi and Epicoccum nigrum. An analysis of minisatellite DNA regions revealed high levels of genetic polymorphism in A. alternata, whereas the remaining isolates were characterized by low levels of genetic variation or genetic homogeneity. The transfer of endophytic fungi between grass species was determined, which was one of the most important observations made in the study. The Sørensen–Dice coefficient reached 50%, which indicates that all fungal species isolated from perennial ryegrass are capable of colonizing timothy grass. 相似文献
7.
L. JONES 《Grass and Forage Science》1990,45(1):83-90
The drying rates of grasses and lucerne, following treatment with 1% formic acid, were compared with those of untreated crops. Material was fully exposed to a flow of air in a ventilated laboratory oven set at 23 °C. Treatment with formic acid initially enhanced the rate of drying of grass, but this was followed by retardation. This reduction in the rate of drying was caused by the rapid desiccation of laminae, which reduced their effectiveness in providing a pathway for water loss from the stem. The rate of water loss directly from the stem surface was not increased by formic acid treatment, probably because the enveloping leaf sheaths acted as a protective layer. In contrast, formic acid increased drying rate in lucerne. whose stems have no such protective layer. The results suggest that chemical desiccants. which have a contact action are unlikely to have any application in making hay from grass. 相似文献
8.
The water loss from tall fescue cv. S170, perennial ryegrass cv. S24, Italian ryegrass cv. R v P and timothy cv. S352 when dried as a thin layer under controlled conditions at 20°C and r.h. 50% is described. Comparisons were made on six occasions between mid-April and mid-June. Tall fescue dried faster than the other species and the time to reach a water concentration of 0·2 g water per g dry matter varied little between the six harvests. In contrast, the drying time for the ryegrasses and timothy increased to maximal values in mid-May and then fell. Drying time was dependent on the initial water concentration of the grass, the ratio of leaf to stem and on the amount of true stem exposed to the drying environment. The practical implications in relation to haymaking are discussed. 相似文献
9.
M. Zeid J.K. Yu I. Goldowitz M.E. Denton Denise E. Costich C.T. Jayasuriya M. Saha R. Elshire D. Benscher F. Breseghello J. Munkvold R.K. Varshney G. Belay M.E. Sorrells 《Field Crops Research》2010
The availability of a large number of expressed sequence tags (ESTs) has facilitated the development of molecular markers in members of the grass family. As these markers are derived from coding sequences, cross-species amplification and transferability is higher than for markers designed from genomic DNA sequences. In this study, 919 EST-based primers developed from seven grass species were assessed for their amplification across a diverse panel of 16 grass species including cereal, turf and forage crops. Out of the 919 primers tested, 89 successfully amplified DNA from one or more species and 340 primers generated PCR amplicons from at least half of the species in the panel. Only 5.2% of the primers tested produced clear amplicons in all 16 species. The majority of the primers (66.9%) were developed from tall fescue and rice and these two species showed amplification rate of 41.6% and 19.0% across the panel, respectively. The highest amplification rate was found for conserved-intron scanning primers (CISP) developed from pearl millet (91%) and sorghum (75%) EST sequences that aligned to rice sequences. The primers with successful amplification identified in this study showed promise in other grass species as demonstrated in differentiating a set of 13 clones of reed canary grass, a species for which very little genomic research has been done. Sequences from the amplified PCR fragments indicated the potential for the transferable CISP markers for comparative mapping purposes. These primer sets can be immediately used for within and across species mapping and will be especially useful for minor grass species with few or no available molecular markers. 相似文献
10.
By controlling the high populations of leatherjackets in two experimental leys it was shown that the loss of grass from this pest could be heavy. The most serious loss occurs in early summer. As soon as the larvae cease feeding in mid-June recovery begins and subsequent growth is satisfactory. Clover is damaged more heavily than grasses, but recovers completely by early autumn. The implications of these experiments are discussed. 相似文献
11.
《Journal of Crop Improvement》2013,27(2):317-333
Summary This paper reviews factors influencing water use and methods to reduce it. Water use in turfgrass typically is quantified by evapotranspiration rate (ET), which refers to the loss of water from the soil through evaporation and from the plant through transpiration. Turfgrass ET rates vary among species and cultivars within a species. Inter-and intraspecific variations in ET rates could be explained by differences in stomatal characteristics, growth rate and habit, canopy configuration, and rooting characteristics. The ET rates also are influenced by environmental conditions and cultural practices. Environmental conditions include climatic factors such as temperature, relative humidity, solar radiation, and wind and edaphic factors such as soil temperature, water availability, and soil texture. Cultural practices include mowing, irrigation, fertility, use of antitranspirants, and plant growth regulators. 相似文献
12.
Germination responses of the halophyte Chloris virgata to temperature and reduced water potential caused by salinity,alkalinity and drought stress 
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下载免费PDF全文 Chloris virgata is considered a useful grass species for grassland restoration in northern China. However, little information exists concerning the germination responses of this species to temperature and water potential caused by stress conditions. Experiments were conducted in growth chambers to assess the effect of temperature, salinity, alkalinity, drought and the interactions of temperature and stress on seed germination. Seeds were germinated at three diurnal temperature regimes, with four water potentials in NaCl, NaHCO3 and PEG solutions. Results showed that optimal germination under stress occurred at 15–25 °C, and germination percentages and rates were inhibited by either an increase or decrease in temperature from the optimal temperature. The inhibitory effects of the low water potential caused by salinity and drought on germination were greater at 25–35 °C, but seeds were subjected to more stress despite the relatively higher water potential because of the alkalinity at this temperature. The recovery percentage under salinity was highest at ?1·2 MPa at 15–25 °C, and more than 80% of seeds also germinated at this water potential after they were transferred from drought stress. However, seeds lost their viability in higher alkalinities under all temperatures, and at 25–35 °C, there was lower recovery percentage under stress. Results suggest that salinity, alkalinity and drought stress have different impacts on seed germination, and the tolerance to stress of C. virgata seeds is affected by the interactions of temperature and water potential caused by salinity, alkalinity and drought. Chloris virgata shows potential utility as a promising grass species in salinity–alkalinity and drought‐stressed environments. 相似文献
13.
Seven species or varieties of grass, and a mixture of 3 of them, were sown in pure swards and treated with 4 levels of nitrogenous fertilizer (0,17·5, 35 and 70lb N per acre per cut). Each species, and the mixture, was also sown with white clover. The experiment was cut 4 or 5 times per year. The effect of fertilizer on the yield of each grass was compared with the effect of clover on the yield of the grass/clover swards. Mean annual yields showed an approximately linear response to N; there was a small but significant fall in response to the highest level of N. Response among the species ranged from 20 to 30 Ib of dry matter per Ib N applied for the intermediate level of fertilizer and from 14 to 23 Ib for the final increment of fertilizer.
S37 cocksfoot, S48 timothy, S24 ryegrass, and a mixture of these grasses, were high yielding and responded well to fertilizer N; Irish ryegrass and Agrostis tenuis were less productive and gave poorer responses to N. S215 meadow fescue and S23 ryegrass were intermediate in yield and response.
There were no significant differences between the annual yields of the 8 grass/clover mixtures; the yields of the grass and clover components of each mixture were inversely related. The effect of clover on the yield of the grass/clover mixtures was estimated to be equivalent to the effect of an annual application of 205 lb N per acre to Agrostis tenuis and 120 lb N to S48 timothy. The fluctuations in annual yields were greater with grass/ clover mixtures than with grass swards receiving N.
The yields of grasses when sown with clover were in similar order to their yields when sown pure; but whereas the latter tended to fall from year to year, the yields of the grass components of mixtures (except Irish ryegrass) did not. 相似文献
S37 cocksfoot, S48 timothy, S24 ryegrass, and a mixture of these grasses, were high yielding and responded well to fertilizer N; Irish ryegrass and Agrostis tenuis were less productive and gave poorer responses to N. S215 meadow fescue and S23 ryegrass were intermediate in yield and response.
There were no significant differences between the annual yields of the 8 grass/clover mixtures; the yields of the grass and clover components of each mixture were inversely related. The effect of clover on the yield of the grass/clover mixtures was estimated to be equivalent to the effect of an annual application of 205 lb N per acre to Agrostis tenuis and 120 lb N to S48 timothy. The fluctuations in annual yields were greater with grass/ clover mixtures than with grass swards receiving N.
The yields of grasses when sown with clover were in similar order to their yields when sown pure; but whereas the latter tended to fall from year to year, the yields of the grass components of mixtures (except Irish ryegrass) did not. 相似文献
14.
15.
燕麦粉不含面筋蛋白,使燕麦全粉面条煮熟后易浑汤、蒸煮损失率大,目前只能温水浸泡复水食用,是限制燕麦更广泛推广的难题之一。为了满足市场对燕麦全粉面条的需求,以利用二级挤压技术生产的燕麦全粉挤压面条为试材,对成型面条进行了调湿老化、蒸制老化及冷冻老化处理,比较了不同老化方式对燕麦全粉挤压面条蒸煮品质的影响。结果表明,调湿老化处理的面条蒸煮损失率最小(2.26%~3.34%),蒸制老化次之(4.19%~5.19%),冷冻老化最大(5.16%~7.97%)。不同老化处理的面条感官评分差异不显著,以调湿老化处理24h的面条感官评分最高(87.2分);调湿老化处理面条的淀粉相对结晶度(12.47%~16.10%)、热焓值(1.044 0~1.056 0J·g-1)及回生值(519.5~558.0cP)均最大,蒸制老化次之,冷冻老化最小。综合分析可知,对燕麦挤压面条进行淀粉老化处理,能够显著降低燕麦全粉挤压面条的蒸煮损失率,最优方式为调湿老化24h。 相似文献
16.
B. H. GREEN 《Grass and Forage Science》1990,45(4):365-372
Grassland in Britain is a plagioclimax vegetation type. All lies on land originally cleared from forest and, without some form of management, would revert to forest through a process of natural succession. Traditionally managed, unsown grasslands nonetheless resemble more natural grasslands in other parts of the world and contain a substantial proportion of our native flora and fauna. They are also often important for recreational activities. Agricultural intensification over a long period has led to a loss in their extent, species and amenity. Reconciling agricultural and environmental objectives in grassland management is very difficult because increased fertility and production invariably leads to species loss. Current overcapacity in the agricultural industry is leading to the switching of some agricultural support from food production to countryside management. As a result some arable and intensively managed grass is being managed more extensively. However future production technologies may be so efficient that very many fewer stock are required with the result that much marginal grassland may revert once again to forest. 相似文献
17.
There is insufficient information about germination, seed biology and seedling establishment of native grass species of the cerrado (Brazilian savannah) to recommend their use in restoration of disturbed areas. We evaluated the production, percentage of fertile seeds, germination, seedling growth and establishment in the field of eighteen native grass species and one exotic invasive species (Melinis minutiflora) and also the effects of different storage periods on germination. The percentage of fertile seeds varied from 6·0 to 94·2% among native species. Ten species produced a minimum of 800 fertile seeds per gram. Germination rate was in the range of 11·0 to 98·8%. Storage for 1 year reduced the germination rate in one species, did not affect germination of three species and increased germination (by 2–10 times) in 14 species. After 2 years of storage, six species showed reductions in germination. Three different patterns of resource allocation were observed and might provide mechanisms for increasing seedling establishment under different environmental conditions. In the field, only two species flowered in the first year after sowing and an additional eight in the second year of observation. Melinis minutiflora is an aggressive species with more than three times the fertile seed production of native species (2820 seeds per gram), high germination rate (55%) and a high number of germinable seeds (1551 per gram). Despite the wide variation in seed characteristics and the delay in flowering, it is concluded that most native grass species can be used in projects aiming at the restoration and management of degraded areas. 相似文献
18.
Previous results with red clover ( Trifolium pratense ) leaflets, leaf petioles and stems indicated that the epidermis continued to impose a barrier to water loss at low water contents. Further experiments with red clover leaf petioles and stems suggest that cuticular wax is the epidermal component concerned and that treatments which remove or merely modify this will also increase drying rate. However, when treatments to reduce epidermal resistance were applied to pseudostems and flowering stems of Italian ryegrass ( Lolium multiflorum ) the initial increase in drying rate produced was not sustained at low water contents. The pseudostems consisted of three layers of leaf material rolled one within the other and the true flowering stems were surrounded by one leaf sheath. Their pattern of response to treatments suggested that these affected only the outer sheath, which produced an initial acceleration in drying rate, but that this was not sustained after the outer sheath was dry because the lower untreated layers dried in a similar way to untreated controls.
The results suggest the possibility of devising practical treatments to increase drying rate at low water contents with crops containing a high proportion of leaf or stem not surrounded by leaf sheath. Devising such treatments for crops with a high proportion of grass pseudostem or flowering stem surrounded by leaf sheath will be considerably more difficult. 相似文献
The results suggest the possibility of devising practical treatments to increase drying rate at low water contents with crops containing a high proportion of leaf or stem not surrounded by leaf sheath. Devising such treatments for crops with a high proportion of grass pseudostem or flowering stem surrounded by leaf sheath will be considerably more difficult. 相似文献
19.
SEASONAL VARIATION IN APPEARANCE AND GROWTH OF GRASS ROOTS 总被引：5，自引：0，他引：5
E. A. Garwood 《Grass and Forage Science》1967,22(2):121-130
Data from two field experiments, and from a root observation trench, suggest an annual cycle of root growth by grass swards. The production of adventitious roots from the tillers of four grass species, and from perennial ryegrass in a grass/clover sward varied greatly during the year. They were produced in increasing numbers through late winter to early spring; this rate fell sharply in April or May, and was low in summer. The differences in this annual cycle between grass species were small. Examination of roots of perennial ryegrass in a glass-sided trench showed that root elongation was most rapid in summer and was largely confined to the lower soil horizons. Rather more roots were produced in early autumn than during summer, but the rate of elongation was slow from October until spring.
Individual roots of grasses appeared to survive for limited periods. Their longevity depended upon the time of year in which they were first formed; those produced in autumn or winter lived longer than those produced in spring or summer. 相似文献
Individual roots of grasses appeared to survive for limited periods. Their longevity depended upon the time of year in which they were first formed; those produced in autumn or winter lived longer than those produced in spring or summer. 相似文献
20.
The herbage production and quality of swards of three grass species, prairie grass (Bromus willdenowii Kunth), reed canary-grass (Phalaris arundinacea L.) and phalaris (Phalaris tuberosa L.) were compared with perennial ryegrass (Lolium perenne L.) and hybrid ryegrass (L. perenne L. ×L. muitiflorum Lam.) under 6–cut (experiment 1) and 4–cut (experiment 2) regimes over 3 years at Ayr; annually, 360 kg ha-1 fertilizer N were applied. At Edinburgh prairie grass was compared with Italian ryegrass (L. multiflorum Lam.), timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.) under an annual 4–cut regime for 3 years (experiment 3); fertilizer N application totalled 350 kg ha-1 annually. Prairie grass gave the highest annual dry matter (DM) production at Ayr, averaging 11·99 t ha-1 in experiment 1 and 15·62 t ha-1 in experiment 2. Reed canary-grass was much less productive whilst phalaris did not persist after harvest year 1. On average, prairie grass gave 8–10% more DM than the three ryegrasses in the 6-cut system but its advantage was much less under the 4-cut regime. In experiment 3, the DM production of prairie grass and Italian ryegrass were similar in year 1, but following winter damage prairie grass gave the lowest production in subsequent harvest years. Prairie grass had digestibility (OMD) values lower than the ryegrass but higher than reed canary-grass, timothy and cocksfoot. The water soluble carbohydrate (WSC) concentrations in prairie grass were markedly higher than in timothy and cocksfoot but lower than those in Italian ryegrass. Prairie grass had relatively low P and Mg concentrations. Reed canary-grass had relatively low OMD and Ca, but high N, P, K and Mg contents. It is concluded that prairie grass may have potential in the UK as a special-purpose species for conservation management but mainly in the milder climatic areas. The Phalaris species evaluated had disappointing agronomic potential. 相似文献