Shorter Flowering Period Research Articles

Higher frequency of legitimate pollinators and fruit set of autotetraploid trees of Libidibia ferrea (Leguminosae) compared to diploids in a mixed tropical urban population.

In mixed-ploidy populations, newly formed polyploids initially occur at low frequencies when compared to diploids. However, polyploidy may lead to morphological and phenological changes, which promote reproductive isolation and favor polyploid establishment and reproductive success. Additionally, previous studies have shown that polyploidy can confer some adaptive advantages to organisms in stressful environments. Here, we investigate variation in reproductive phenology, floral traits and reproductive success between diploid and autotetraploid trees of Libidibia ferrea (Mart. Ex Tul.) L.P. Queiroz (Leguminosae) in a mixed tropical urban population, a stressful environment. We assessed ploidy levels, flowering and fruiting phenology, flowering synchrony, floral and reproductive biology, pollination and fruit and seed set. We tested the hypothesis that autotetraploid individuals have a higher frequency of pollinators and higher fruit and seed set per inflorescence (as a proxy of reproductive success) than diploids in an urban green space. Libidibia ferrea is a good model to test our hypothesis because it is self-incompatible (i.e. relies on pollinators to set fruits). In the urban ecosystem studied, we found that diploids flowered for 6-7 months/year and autotetraploids for 3-5 months/year. Flowering synchrony was low between and within cytotypes and even though autotetraploids and diploids exhibited some overlap in flowering period, diploids flowered alone for 2-3 months. Autotetraploids had significantly more flowers per inflorescences, larger flowers and larger pollen grains (as expected for polyploids), but also a higher frequency of visits by legitimate pollinators including two exclusive ones, and higher fruit and seed set per inflorescence when compared to diploids, despite having a shorter flowering period. Our findings reveal some advantages for polyploids over their related diploids in a tropical urban green space. Also, our results highlight the need for more studies that seek to understand abiotic mechanisms affecting reproductive output of polyploids in urban ecosystems.

Reducing Flower Competition for Assimilates by Half Results in Higher Yield of Fagopyrum esculentum.

Despite abundant flowering throughout the season, common buckwheat develops a very low number of kernels probably due to competition for assimilates. We hypothesized that plants with a shorter flowering period may give a higher seed yield. To verify the hypothesis, we studied nutrient stress in vitro and in planta and analyzed different embryological and yield parameters, including hormone profile in the flowers. In vitro cultivated flowers on media with strongly reduced nutrient content demonstrated a drastic increase in degenerated embryo sacs. In in planta experiments, where 50% or 75% of flowers or all lateral ramifications were removed, the reduction of the flower competition by half turned out to be the most promising treatment for improving yield. This treatment increased the frequency of properly developed embryo sacs, the average number of mature seeds per plant, and their mass. Strong seed compensation under 50% inflorescence removal could result from increased production of salicylic and jasmonic acid that both favor more effective pollinator attraction. Plants in single-shoot cultivation finished their vegetation earlier, and they demonstrated greater single seed mass per plant than in control. This result suggests that plants of common buckwheat with shorter blooming period could deliver higher seed yield.

Exposure to heat stress during flowering period reduces flower yield and pyrethrins in Pyrethrum (Tanacetum cinerariifolium)

AbstractHeat stress is one of the major limitations to crop productivity worldwide. Global warming effects are expected to increase the number of hot days and increase the probability and intensity of heat stress events. Short periods (3–5 days) of heat stress with maximum temperatures exceeding 35°C often occur during late spring and early summer in some pyrethrum growing regions of Australia. These heat stress events usually coincide with pyrethrum flowering period. Pyrethrum is a perennial herbaceous plant which is commercially grown for extraction of pyrethrins which accumulate in the achenes of the flowers and are used as a natural insecticide. This experiment was conducted to understand the effects of timing of short periods of heat stress on flower development and pyrethrum yield. Plants were subjected to short periods of high temperature treatments (12 hr at 35–40°C) for three consecutive days at three flower maturity stages (early, mid, late). Control plants were grown at ambient temperature (10–25°C) throughout the flowering period. Exposure of pyrethrum plants to short periods of high temperature during the flowering period caused a significant reduction in the flower and pyrethrin yield. This was associated with the reduction in flower size and accelerated flower senescence. Exposure of pyrethrum plants to heat stress significantly increased the rate of flower development resulting in a shorter flowering period. Overall, plants grown under control treatment showed slower rate of flower development and longer duration flowering period. This resulted in longer duration of pyrethrin accumulation and higher yield of pyrethrins per flower. Timing and duration of heat stress significantly influenced pyrethrin yield per flower. Heat stress caused more severe yield reductions at early flowering than later in the flowering period. Research focusing on agronomic strategies, phenology and breeding for tolerance to heat stress is therefore important to cope with future climate changes and to obtain maximum pyrethrin yield.

A rare duodichogamous flowering system in monoecious Toona sinensis (Meliaceae)

BackgroundDuodichogamy is the rarest form of dichogamy in angiosperms, which is characterized by flowering in the sequence of male→female→male. Disentangling factors promoting duodichogamy require the discovery of more duodichogamous species in angiosperms. However, extremely limited information on duodichogamous species makes it difficult to make general conclusions. Given the inflorescence morphology and flowering characteristics, the Meliaceae family is highly likely to contain duodichogamous species.MethodsWe selected 48 individuals from 20 populations in Korea and investigated their flower morphology, arrangement of flowers by sexual condition within inflorescences, and flowering phases and duration of male and female flowers of Toona sinensis (Meliaceae) for 5 years (2011–2015) to determine if the species shows duodichogamous flowering.ResultsToona sinensis belonging to Meliaceae possessed functionally unisexual flowers with rudimentary parts of the opposite sex. The floral organs in male were larger than those in female, except for ovary length and width. In dichasium, male flowers were observed on primary or lateral branches, whereas female flowers were borne only on lateral branches. Overall, individuals from six different populations flowered in the male→female→male sequence, thereby male is blooming far longer than female flowers at the level of individual trees (male vs. female = 17–20 days vs. 2–4 days).ConclusionsThis is the first study to report a duodichogamously flowering species, T. sinensis, within Meliaceae. Several flowering characteristics observed from T. sinensis may be important clues used to discover additional duodichogamous Meliaceae species. Short flowering period and relatively small number of female flowers, which is analogous to reduced ovule numbers observed in other duodichogamous species, may intensify male–male competition in T. sinensis. This study contributed to narrowing down potential candidates of duodichogamy based on their geographic distributions and flowering time.

Pulsating electrolyte flow in a full vanadium redox battery

Proper management of electrolyte flow in a vanadium redox battery (VRB) is crucial to achieve high overall system efficiency. On one hand, constant flow reduces concentration polarization and by extension, energy efficiency; on the other hand, it results in higher auxiliary pumping costs, which can consume around 10% of the discharge power. This work seeks to reduce the pumping cost by adopting a novel pulsing electrolyte flow strategy while retaining high energy efficiency. The results indicate that adopting a short flow period, followed by a long flow termination period, results in high energy efficiencies of 80.5% with a pumping cost reduction of over 50%.

Pod Set in Soybean: Investigations with SOYPODP, a Whole Plant Model

The ability of soybean [Glycine max (L.) Merr.] to adjust its pod load to environmental conditions is an important, but not well understood, part of the yield production process. To better understand this process at the whole plant level, a single‐node model (SOYPOD) was extended to predict pod set of whole plants. Pod survival in SOYPODP was determined by comparing assimilate from photosynthesis (calculated from solar radiation) to pod requirements during initial pod growth. Measured profiles of flowers per node and pod and seed growth rates were used as input. Pods that do not receive adequate assimilate for a specified number of consecutive days do not survive. When inter‐nodal movement of assimilate was prohibited and the nodal assimilate production profile matched the input flower profile, pod set on the stem matched measured profiles of two field‐grown cultivars. In this form, SOYPODP accurately mimicked known responses of pod number to variation in assimilate supply, nodes per plant and individual seed growth rate. Competition for assimilate at a node‐controlled pod set, so increasing uniformity of pod development (more flowers or a shorter flowering period) increased pod set. Increasing nodal variation in the beginning of pod development reduced the sensitivity of the plant to short‐term fluctuations in assimilate supply. Variation in uniformity of pod development at a node was responsible for increases in pod set with no change in assimilate availability. The value of these increases is not clear, but it seems unlikely that they would affect yield.

Short-Term Flow Induced Crystallization in Isotactic Polypropylene: How Short Is Short?

The so-called “short-term flow” protocol is widely applied in experimental flow-induced crystallization studies on polymers in order to separate the nucleation and subsequent growth processes [Liedauer et al. Int. Polym. Proc. 1993, 8, 236–244]. The basis of this protocol is the assumption that structure development during flow can be minimized and the rheological behavior, i.e., the viscosity, does not change noticeably. In this work we explore the validity of this assumption for short but strong flows and reveal the structure formation during the early stages of crystallization. Viscosity and structure evolution of an isotactic polypropylene (iPP, Mw ≈ 365 kg/mol and Mw/Mn = 5.4) melt at 145 °C are measured during the short-flow period (0.2–0.25 s) using the combination of a slit rheometer and fast X-ray scattering measurements. For high enough (apparent) shear rates (≥240 s–1) a viscosity rise during flow is observed; i.e., the condition for “short-term flow” is not satisfied. With a time delay with respect to the viscosity rise, the development of shish is observed at a position halfway the length of slit, along the flow direction, by means of ultrafast time-resolved SAXS measurements. Depending on the shear rate, these shish are detected during (shear rates ≥ 400 s–1) or after flow (240 s–1 ≤ shear rates < 400 s–1). For even lower shear rates of 160 and 80 s–1, the viscosity does not change significantly, and instead of shish, oriented row nuclei (X-ray undetectable) are generated. These two shear conditions qualify as short-term flow. A full understanding of the coupled flow and crystallization phenomena requires that the transient and nonhomogeneous behaviors, both in flow and in flow gradient direction, have to be taken into account. This can only be done by a full numerical model, and therefore, the results presented in this paper also provide a valuable data set for future numerical studies.

Flowering patterns of &lt;i&gt;Thymelaea velutina&lt;/i&gt; at the extremes of an altitudinal gradient

m a.s.l.). We determined the relationship between three components of flowering phenology: initial date, flower duration, and synchrony, and assessed their association with traits describing plant size and fecundity. The increase in altitude results into a delayed flowering initiation and a shorter flowering period. In both habitats, male plants flowered earlier and for longer periods than females. At the mountain site, fruit set was associated to flower initiation, so that plants flowering earlier produced greater proportions of fruits. By contrast, fruit set at the dune site did not depend upon either flower initiation or flowering period; here, larger plants had longer flowering periods, though not necessarily produced more flowers and did not set more fruits than smaller plants. We attribute the differences in flowering patterns at different altitudes to phenotypic plasticity of the species; it is adapted to mountain conditions delaying the flowering period (probably adjusting it to the insect abundance at this altitude). Moreover, shortening of the flowering period may be also advantageous to reduce the stressful effects of higher temperature, radiation and drought that occur later in the summer.

Plant phenological response to microclimatic variations in an alpine zone of Garhwal Himalaya

The impact of microclimatic variations on the developmental stages of common alpine plant species at four primary phenology sites at Dayara meadow of Garhwal Himalayas (Uttarakhand) was studied. The study revealed that the variations in the topographical features and environmental conditions directly influenced the phenology of the alpine plant species. Site I and IV showed great variation in the timing of phenological phases whereas, site III and IV showed approximately similar phenological timings. Anemone obtusiloba and Anaphalis contorta showed early flowering whereas Aconitum heterophyllum, Bupleurum longicaule and Parnassia nubicola flowered in late August and early September. P. nubicola had a shorter flowering period whereas Tanacetum longifolium.and A. nepalensis had the longest flowering period. Taraxacum officinale and Geum elatum flowered twice in the season.

Floral ecology of Oreocharis acaulis (Gesneriaceae): An exceptional case of “preanthetic” protogyny combined with approach herkogamy

Protogyny is supposed to represent the ancestral form of dichogamy in the angiosperms, but is rare in advanced groups such as the Asteridae, in which protandry prevails by far. Here we report on an unusual form of protogyny combined with herkogamy in a Chinese species of Gesneriaceae (Asteridae–Lamiales): Oreocharis acaulis (formerly Opithandra acaulis). This is characterized by a conspicuous protrusion of the style from the flower bud and the stigma becoming receptive before corolla opening (female-only stage; preanthetic protogyny) and both sexes staying functional during anthesis (hermaphroditic stage), with the stigma presented above the anther level (approach herkogamy). The plants studied were found to be self-compatible, but autonomous self-pollination and apomixis were not observed. Successful pollination was found to depend fully on the presence of insect pollinators (Bombus sp.). The visiting frequency was higher in the hermaphroditic stage (in which also more nectar was produced) than in the female-only stage. The out-crossed flower buds opened earlier and had a shorter flowering period than selfed flowers. Similarly, the outcross-pollen germinated earlier and the pollen tube growth was faster than in self-pollen. Anthers, pistil and corolla of O. acaulis obviously form an integrative functional unit in which the elongated style plays a key role both in pollen-dispensing and pollen-deposition. The combination of preanthetic protogyny with herkogamy has probably arisen through selection for promoting out-crossing and prolonging the exposition time of the receptive stigma in order to capture a higher amount of pollen grains. This may be understood as a strategy to cope with scarcity of pollinators in the plants’ habitat.

The common bean growth habit gene PvTFL1y is a functional homolog of Arabidopsis TFL1

In a common bean plant exhibiting determinate growth, the terminal shoot meristem switches from a vegetative to reproductive state, resulting in a terminal inflorescence. Contrary to this, indeterminate growth habit results in a terminal meristem that remains vegetative where it further regulates the production of lateral vegetative and reproductive growth. In the last century, breeders have selected determinate growth habit, in combination with photoperiod insensitivity, to obtain varieties with a shorter flowering period, earlier maturation and ease of mechanized harvest. Previous work has identified TFL1 as a gene controlling determinate growth habit in Arabidopsis thaliana. In this work, we have validated that the Phaseolus vulgaris candidate gene, PvTFL1y, is the functional homolog of TFL1 using three independent lines of evidence. First, in a population of ~1,500 plants, PvTFL1y was found to co-segregate with the phenotypic locus for determinate growth habit (fin) on chromosome 01. Second, using quantitative PCR, we found that two unique haplotypes associated with determinacy at the PvTFL1y locus, a 4.1-kb retrotransposon and a splice-site mutation, cause mRNA abundance to decrease 20-133 fold, consistent with the recessive nature of fin. Finally, using a functional complementation approach, through Agrobacterium-mediated transformation of determinate Arabidopsis, we rescued tfl1-1 mutants with the wild-type PvTFL1y gene. Together, these three lines of evidence lead to the conclusion that PvTFL1y is the functional homolog of the Arabidopsis gene, TFL1, and is the gene responsible for naturally occurring variation for determinacy in common bean. Further work exploring the different haplotypes at the PvTFL1y locus may lead to improved plant architecture and phenology of common bean cultivars.

Effects of below- and above-ground herbivores on plant growth, flower visitation and seed set

Separate and combined effects of root and leaf herbivores on plant growth, flower visitation and seed set were tested in a factorial experiment using potted mustard, Sinapis arvensis, at an old fallow field. A 50% leaf removal by cabbageworms (Pieris rapae) when the seedlings had their first four leaves reduced plant height and shoot mass, and delayed the onset of flowering. Root herbivory by two wireworms (Agriotes sp.) over the whole experiment changed flower visitation; the number of flower visitors per plant was higher in plants with root herbivores than in plants without root herbivores. Combined leaf and root herbivory affected flowering period, number of fruits per plant and number of seeds per fruit. Plants attacked by leaf and root herbivores had a shorter flowering period and produced fewer fruits per plant than plants with root herbivores only. Although the experimental plants faced major herbivore-induced growth changes, plant reproduction (seed set and weight per plant) was similar in all treatments, documenting their ability to effectively compensate for leaf and root herbivory.

Flowering and pod and seed development in pigeon pea (Cajanus cajan)

SUMMARYFlower, pod and seed development were studied in the cultivars Cita-1 and Cita-2 in two field trials in 1985–86, in Ibadan, Nigeria. Flowering within any inflorescence was acropetal. On each plant the terminal inflorescence was the first to flower and, generally, inflorescences developed basipetally. A total of 569 flowers (mean of five plants) opened on Cita-1; of these, 20 were on the terminal inflorescence, 130 on axillary inflorescences and 419 on inflorescences on primary branches. For the 605 flowers (mean of five plants) which opened on Cita-2, the distribution was 19, 161 and 425, respectively.On Cita-1, 158 pods formed on average, of which 7 were on the terminal inflorescence, 33 on axillary inflorescences and 118 on inflorescences on primary branches lower down the plant. On Cita-2, for the 185 pods counted at maturity, the distribution was 8, 43 and 134, respectively. Some 72 and 69% of the total number of flowers which opened on Cita-1 and Cita-2, respectively, were aborted. In both cultivars, 99% of the mature pods were formed from flowers which opened within 24 days of the start of anthesis; the number of pods retained largely determined seed yield. The inflorescences which developed on the primary branches contributed 70% (Cita-1) and 66% (Cita-2) of the total seed yield. Early-formed pods were heavier than those formed later. Individual pods attained physiological maturity 35–42 days after successful pollination of the flower. At physiological maturity of the pod, the seed contained 3·72 % N, 0·45% P and 2·76% K, and the husk contained 1·98% N, 0·16% P and 1·96% K. The majority of open flowers which aborted were produced on primary branches, indicating that the primary branches have the greatest potential for increasing seed yield. A shorter flowering period might ensure greater retention of open flowers.

Inhibition of flowering of Mexican- and Guatemalan-type avocados under tropical conditions

Avocado trees of a range of cultivars growing in Darwin, northern Australia (average yearly maximum 33°C, minimum 23°C), were observed for flower and shoot development. Terminal buds of the cultivars ‘Fuerte’, ‘Rincon’ and ‘Edranol’ sampled in July were not floral. Buds which did not burst were sampled in September and they contained developing flowers with perianth primordia. Vegetative extension growth resulted from laterals proximal to the inhibited terminal buds. Avocado trees of the cultivars ‘Fuerte’ and ‘Hass’ which had initiated floral buds were transferred to controlled environment chambers with 33°C day, 23°C night ( 33 23 ) or 25°C day, 15°C night ( 25 15 ) with a 12-h photoperiod and photon flux density of 400 μmol m −2 s −1 (400–700 nm). At 33 23 the trees had fewer flowers and a shorter flowering period than at 25 15 . Inhibited floral buds and lateral vegetative extension resulted at 33 23 , as observed in northern Australia. The unburst buds had developing flowers with perianth and stamen primordia. The controlled environment experiments showed that the abnormal flushing behaviour of Mexican- and Guatemalan-type avocados growing in northern Australia was due to high temperature. Floral development was inhibited at the stage of stamen differentiation.

Response of Soybean to Two Levels of Mineral Nutrition in CO2‐Enriched Atmosphere1

Studies conducted with increased atmospheric CO2 usually have the nutritional supply being either optimal or not monitored. The expected increase in growth rate and production by plants in an enriched CO2 atmosphere that is predicted for the future could be limited through the rapid depletion of mineral nutrients in the root media. The objective of this study was to investigate the effect of atmospheric CO2 enrichment on soybean (Glycine max L. Merr. cv. Ransom) plants grown under two nutritional levels. Plants were grown from seed in a mixture of gravel, vermiculite, and tnrface in controlled environment chambers at 350 or 675 ppm CO2 and were irrigated with one‐eighth or one‐half strength Hoagland's solution No. 1. The temperature was 26 C during the 12‐hour day, and 20 C during the 12‐hour dark period. The photosynthetic photon flux density was 550 μE m‐2 sec‐1. Plants grown in one‐half strength Hoagland's solution produced more branches, total leaf area, and total blomass at each CO2 concentration than those grown in one‐eighth strength Hoagland's solution. Specific leaf weight increased with increased CO2 concentration in both nutritional levels. Plants grown in low nutrient supply at low CO2 concentration had a shorter flowering period and produced fewer towers, pods, and seeds due to the abortion of some flowers and senescence of pods. Total plant weight and seed number were greater with the high nutrient level than with the low nutrient level under similar CO2 concentrations. Plants grown at 675 ppm CO2 and receiving one‐eighth strength Hoagland's solution produced more biomass and total seed yield than plants grown at 350 ppm CO2 and one‐half strength Hoagland's solution. Therefore, the limiting effect of nutrient supply could partly be overcome by the increase in atmospheric CO2 concentration.

Analysis of Short-Time Buildup Data for Finite-Conductivity Fractures

Summary A finite-conductivity vertical fracture intersecting a well is considered. The well is produced at a constant rate or at a constant pressure and then is shut in. The pressure response during the buildup period and the pressure or rate response during the production period are obtained from a numerical model. In this work we discuss the analysis of pressure buildup data following a short flow period. We present a buildup type curve to analyze pressure buildup data when the pressure (or rate) response is influenced by only the bilinear flow period. This type curve can be used to estimate the fracture flow capacity and a lower limit for the fracture half-length. It will be useful when the equivalent-time or the equivalent-drawdown concepts cannot be used. We discuss strengths and limitations of the equivalent time method proposed in the literature. The theoretical basis for this procedure is provided. Introduction Virtually all type curves available in the literature are intended for analysis of drawdown data and thus can be used to analyze buildup data only if the producing time before shut-in is significantly longer than the buildup time. Although this limitation is stated in the literature as far back as 1970, the consequences of using the drawdown type curves to analyze pressure buildup data measured after a short flow period were documented only recently. Buildup type curves that take into account the influence of producing time also are presented in Ref. 1. More recently, attempts have been made to bypass the buildup type curves and to use the drawdown curves directly. Raghavan et al. Suggests that buildup data can be converted to drawdown data and thus that the drawdown type curves can be used directly. This is the most accurate procedure available since it involves a minimum number of assumptions, but it does require that drawdown data be available unless Delta t/t less than 0.1 or Delta t/t &amp;gt;1. The principal advantage of the method is that it allows analysis of buildup data when Delta t &amp;gt;t. This is extremely important if the producing time before shut-in is small. An alternative procedure suggested by Agarwal involves a modification of the time scale and is known as the equivalent-time method. Theoretically, the method is valid only if plane radial flow prevails. However, Agarwal was able to demonstrate empirically that this technique applies to fractured wells. The principal objectives of this paper areto show that the normal form of the drawdown type curves for finite-conductivity fractured wells is inadequate to analyze buildup data following a short flow period,to present a modified version of these curves to analyze short-time data (drawdown or buildup),to present a buildup type curve suitable for analyzing data measured after a short production period,to discuss the strengths and limitations of the equivalent-time method, andto establish a theoretical basis for this procedure and to explain the empirical findings of Agarwal. 3 The buildup type curve presented here can be used to analyze tests in fractured wells when the response during the flow period is dominated by the bilinear flow regime. The type curve should prove useful when the other two methods suggested in the literature cannot (or should not) be used. Definitions All results given in this study are presented in terms of dimensionless variables. The dimensionless variables are defined in the following equations. JPT P. 2413^

Analysis of Pressure Buildup Data Following a Short Flow Period

Summary Methods for analyzing buildup data following a short flow period are presented, discussed, and illustrated. A new type curve for uniform-flux and infinite-conductivity vertically fractured wells is presented. By matching buildup data with this new type presented. By matching buildup data with this new type curve, we can determine the dimensionless flowing time before shut-in. A method for converting buildup data to equivalent drawdown data is discussed. This method can be used to combine buildup and drawdown data to obtain a longer band of data for type-curve matching. This method canbe used for constant-rate production, constant-pressure production, and for the case where both pressure and rate production, and for the case where both pressure and rate vary during production. Introduction Over the past decade, the use of type-curve matching toanalyze pressure data has gained increasing acceptance. The advantages and dis advantages of type-curve matchingare well recognized and the procedure has become astandard tool to analyze data qualitatively, to identify flow regimes, and, quantitatively, to determine iformation parameters. Virtually all type curves available in the literature examine the pressure response at a flowing well-i.e., only drawdown solutions have been examined. These type curves may be used to analyze shut-in pressure behavior provided that the flowing time before shut-in is provided that the flowing time before shut-in is significantly longer than the maximum shut-in time. This limitation has prevented type-curve analysis ofpressure buildup data following short flow periods. pressure buildup data following short flow periods. The effect of a short flow period on pressure buildup data influenced by either wellbore storage or vertical fractures was presented recently. It was shown that significant errors result if proper care is not taken in analyzing pressure buildup data when the producing timeis short. Procedures to account for the influence of producing time were outlined. producing time were outlined. The objectives of this paper areto present anew correlation that considerably simplifies the use of buildup type curves for vertically-fractured wells givenin Ref. 1, andto suggest a procedure to analyze pressure buildup data by means of drawdown type pressure buildup data by means of drawdown type curves. The procedures discussed here can be applied to single- or multiwell tests, to data obtained after shortor long flow periods, to constant or variable flow rates, and to virtually all wellbore conditions including data influenced by wellbore storage and skin and fracturesof finite or infinite conductivity. Theory The basic pressure buildup equation based on the principle of super position is given by principle of super position is given by (1) Here, t is flowing time and Delta t is shut-in time. Thesymbols p and t denote dimension less wellbore pressure drop and dimension less time, respectively, and are defined as follows. JPT P. 904

Practicalities of Detecting Faults From Buildup Testing

The influence of a sealing fault (and other linear discontinuities) on transient well tests is a widely discussed subject. The topic first was presented by Horner for pressure buildup testing. Fig, 1 illustrates ideal pressure behavior in a tested well near a fault. This figure is a schematic semilog plot that applies to any kind of single-well transient test; doubling of the straight-line slope is the key to the existence of a fault. The material presented in this paper applies to falloff and buildup tests. It does not paper applies to falloff and buildup tests. It does not apply to flowing-only tests, such as drawdown, injectivity, and multiple-rate flow tests. The information in this paper assumes horizontal radial flow in a homogeneous, unfractured reservoir and assumes that wellbore storage effects are unimporant.There an pitfalls in detecting faults (used here to mean any linear discontinuity) from pressure buildup and falloff tests that generally are not recognized. The reason is that flow time determines how much reservoir a test investigates. So, for a pressure buildup test, the flow time before shut-in determines if it will be possible to recognize a fault from buildup data. If flow time is long enough, then the shut-in time need only be long enough to obtain data that show the dope doubling. A shortflow time cannot be compensated for by a long shut-in time. Interestingly enough, the pressure behavior caused by a fault is such that if shut-in time is not long enough to show the double slope, it is possible to interpret the data incorrectly as indicating a small closed system rather than a large system with a nearby fault.Flow times too short to detect faults during buildup testing are particularly apt to occur in two common types of well testing. One is drillstem testing, which generally has a short flow period. The second is the testing of a gas well where no pipeline facilities are available, so a short flow period is used while the shut-in period may last weeks or months.The theory describing pressure behavior in a well near a fault is relatively simple. Fig. 1 shows pressure buildup curve shape and indicates that the pressure buildup curve shape and indicates that the second slope, m2, is twice the first slope, m1. From the first slope, one calculates skin factor and permeability. permeability. The doubling of the slope is a strict theoretical requirement and not an approximation. P. 18

Breeding for improvement of flowering attributes of winterhardy rosa kordesii Wulff hybrids

The results from tetraploid hybrids of R. kordesii showed that flowering attributes can be improved by a suitable combination of modifying factors as was shown previously by investigations with diploid hybrids from R. rugosa. A longer flowering period than 7 weeks indicated always the ability for recurrent bloom in these investigations but a shorter flowering period did not always indicate non-recurrent bloom.

Pulse Tests and Other Early Transient Pressure Analyses for In-Situ Estimation of Vertical Permeability

Abstract Formation vertical permeability is often the dominant influence in water or gas coning into a well, in gravity drainage of high-relief reservoirs, and in interlayer crossflow in secondary recovery projects. The advantages of either conducting a projects. The advantages of either conducting a pulse test or analyzing the early transient pressure pulse test or analyzing the early transient pressure response of a constant-rate test compared with previous techniques are simplicity of interpretation, previous techniques are simplicity of interpretation, short duration of test, and minimum interference from conditions some distance from the test well. The pulse test has a further advantage over the constant-rate test in that the rate does not have to be kept constant during the short flow period. Presented are the development of the theory and the curves of the dimensionless response time used in interpreting field data obtained by these techniques. The vertical permeability is determined with the pulse test from the time to the maximum pressure response and with the constant-rate test pressure response and with the constant-rate test from the extrapolated time to zero pressure response from the inflection point. Applications of the techniques to layered systems and to an oil zone with underlying water are demonstrated with results of numerical simulations. The vertical-permeability pulse test has been used to estimate the vertical permeability of a low-permeability zone in the Fahud field, Oman. Introduction The formation vertical permeability is often a dominant influence in reservoir recovery processes with vertical fluid flow such as water or gas coning, gravity drainage of high-relief reservoirs, the rising steam process, and displacement by water or gas in a heterogeneous formation. How reliably numerical reservoir simulators can predict the recovery performance of these processes depends upon how performance of these processes depends upon how accurately the significant reservoir parameters are estimated. Furthermore, in simulating a reservoir in two dimensions, the validity of the assumption of vertical equilibrium is based on the value of the vertical permeability. With the previously mentioned recovery processes, the reservoir cannot be modeled as a homogeneous reservoir with a single fluid. A well that has fluid coning or that is producing by gravity drainage will often have a fluid contact intersecting the well and thus dividing the reservoir into zones of differing mobility and compressibility. Reservoir stratification on a microscopic scale will result in a vertical permeability that is less than the horizontal permeability that is less than the horizontal permeability; but stratification on a macroscopic permeability; but stratification on a macroscopic scale will divide the reservoir into zones of differing permeabilities. Thus the design and interpretation permeabilities. Thus the design and interpretation of a vertical-permeability test for most practical reservoir situations will require that the reservoir zonation be represented. Transient pressure techniques for estimating in-situ vertical permeability have been introduced by Burns and by Prats. Both techniques require injection or production at a constant rate from a short perforated interval and measurement of the pressure response at another perforated interval pressure response at another perforated interval that is isolated from the first by a packer. The interpretation technique of Burns required a computer-generated type curve or a single-phase numerical reservoir simulator. This type-curve approach is applicable for an anisotropic, homogeneous, infinite reservoir model, and the numerical simulator with a regression analysis program is needed for finite or layered reservoir models. The technique presented by Prats did not require a computer program because the result of the analysis was presented on a single graph. The horizontal and vertical permeabilities could be estimated from the slope and the intercept of the pressure response and, the appropriate value from the graph. The method of Prats was based on an infinite, anisotropic, Prats was based on an infinite, anisotropic, homogeneous reservoir model.The pulse test and early transient analysis techniques presented here were developed to provide a simple means of interpretation for layered provide a simple means of interpretation for layered systems.