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1.
Summary

The effect of deshooting of flowering stems of rose cv. Motrea as compared with normal harvesting procedure was studied with respect to carbohydrate storage and subsequent flower production after downwards pruning of shoots. Growth analyses over two periods were conducted to calculate total biomass production and partitioning. Soluble sugars and starch in samples of the stem taken at several heights in the plant were also analysed. In general, starch concentrations increased and sugar concentrations decreased from upper to lower stem parts. Deshooting increased total non-structural carbohydrates, mainly caused by starch. The stored carbohydrates were used during a subsequent flowering cycle. Total extra carbohydrate reserves due to the deshooting practice could explain the resulting increase in fresh-weight production. Biomass production was not influenced by treatments over the experimental period but deshooting greatly reduced flower production and enhanced the weight of discarded prunings. It is concluded that treatments primarily directed at redistribution of carbohydrates are probably of little use in improving the management of a rose crop.  相似文献   

2.
Rose plants that are flush harvested exhibit episodic growth patterns. During these crop cycles little biomass accumulation occurs immediately following harvest; and as new shoots emerge a period of rapid shoot growth and biomass accumulation occurs. The temporal changes in whole-plant nutrient and carbohydrate distribution during these crop cycles and the role of storage in new shoot growth are not well documented. The objective of this project was to quantify N, P, K, and total non-structural carbohydrates (TNC) distribution in roots, base stems, base leaves, and new shoots during crop cycles in response to light availability. Plants were grown in solution culture under high or low light (mean daily light integral 45.3 or 13.1 mol m−2 d−1, respectively) during 30–35 day crop cycles. Every five days destructive sampling was used to determine biomass and N, P, K, and TNC concentration of rose plant compartments. N and TNC accumulated in base plant compartments during the first ten days of the crop cycles. N, P, K, and TNC in base plant compartments declined during days 10–25 during a crop cycle concurrent with the rapid growth of flower shoots. N, P, and K storage in base plant parts represents 27, 22, and 24% of the potential N, P, and K required by flower shoots under high light; and 19, 21, and 22% of requirements under low light. TNC storage in base plant parts represents 4–10% of the final biomass of flower shoots. Mobilization of N, P, K, and TNC stored from base plant parts appears to be important during the stage of rapid flower shoot growth when absorption by roots or photosynthesis by shoots was insufficient to meet flower shoot demands. Plant carbohydrate status was improved under high light conditions; storage of N and TNC declined under low light.  相似文献   

3.
Summary

Changes of carbohydrate concentrations in different parts of the flower and the surrounding tissues (leaves, spurs and shoots) were measured in apple (Malus pumila) in 1987 and 1988, during the periods of flowering and fruit setting, to investigate their importance for fruit setting. HPLC was used for soluble sugar and sorbitol analysis. Starch was hydrolysed to glucose enzymatically and glucose concentration was determined colorometrically to estimate starch concentrations. Soluble sugars plus sorbitol (the soluble pool) increased rapidly in all parts of the flower from bud burst until full bloom. In contrast, in the same period, starch concentrations decreased rapidly and reached about zero at full bloom in the storage organs (shoots and spurs), indicating starch conversion to sugars and their movement to the growing flowers. Sorbitol was the most abundant carbohydrate in all apple tissue measured, with the exception of sepals, in which glucose concentration was the highest from full bloom onwards. Sepals had much higher glucose and fructose concentrations than leaf laminae but much lower sorbitol concentrations. Although dry weight, soluble pool and starch concentrations and total soluble pool content increased in the receptacle after petal fall, sucrose concentrations and total sucrose content dramatically decreased. These results suggest a preferential mobilization and utilization of sucrose rather than sorbitol during the fruit setting period and probably an important role of sucrose metabolism in fruit setting.  相似文献   

4.
Summary

Patterns of distribution of 14C-sucrose were determined in egg plant (Solanum melongena L.) cv. Arka Shirish at the vegetative, flowering and fruit development stages. 5 μCi of 14C-sucrose was fed to the fifth leaf from the top at each growth stage and the plants were harvested, 48 h after feeding or at later stages, and the distribution of l4C-sucrose determined. Results indicated bidirectional transport of assimilates to both apical and basal portions of the stem. Within 48 h 14C moved to all the plant parts; roots, stem and leaves appeared to be strong sinks until the fruit began to develop. In plants fed at the fruit development stage, the fruit below the fed leaf were a major sink, although considerable activity was traced in other plant parts also. Only at later stages of crop growth did the fruit become a strong sink. Even at the fruit development stage, about 5-8% of the activity was still found in the roots and no retranslocation to fruit was observed.  相似文献   

5.
Carnations, cultivar ‘White Sim’, were planted on 17 January, 12 March, 11 July, 12 September and 7 November, at densities of 12.9, 25.8, 51.7 and 103.3 plants m?2. For each planting-date, yields within a year from planting were asymptotically related to plant density. The mid-winter plantings gave the highest yields and the July planting the lowest.Yield patterns, derived from a weighted moving average, were affected by both the date and the density of planting. At high density, a major part of the year's yield came from the first flush, accounting for 48% of the total yield in the September planting and 75% in the March planting. At the low density, the first flush was only 26–31% of the year's yield. After the first flush, crop yields were suppressed more at higher densities, especially in the November, January and March plantings. Densities of 25.8 and 51.7 plants m?2 gave the best continuity of production per unit area, whilst the lowest density gave the best continuity of production per plant.The suppression of flower initiation was related to the amount of light; in November less than 20% of the incident light penetrated the canopy of a high-density September planting. Continuous light did not materially increase the number of shoots per plant that initiated flowers, its greatest effect being to produce earlier initiation.  相似文献   

6.
Summary

The opening of gladiolus florets was accompanied by a substantial increase in fresh and dry weight and carbohydrate content of the perianth. The principal soluble carbohydrate was fructose, with substantially lower concentrations of glucose and sucrose. Although stored carbohydrate, apparently starch, disappeared during floret opening, its contribution to the total carbohydrate content of the open flower was minor. Removal of basal florets from the freshcut spike substantially reduced the dry weight of the opening upper young buds. During development of the inflorescence it appears that there is a transfer of carbohydrate from the senescing lower florets to those developing acropetally.  相似文献   

7.
Flowering and fruit-setting in the sweet orange cv. ‘Late Valencia’ were observed for three consecutive seasons that comprised two “off-years” and one “on-year”. Twice as many flowers per unit area of tree canopy were observed in the “on-year” as in the two “off-years”. There was a significant negative correlation between the yield of the previous crop and the number of flowers per square yard of tree canopy.

There were no significant differences between an “off-year” and an “on-year” in the proportions of inflorescences classified according to the number of flowers and number of leaves per inflorescence. Furthermore, the previous crop had no direct effect on fruit-set, the percentage fruit-set being similar in all three seasons.

Observations made during blossoming, when the trees were bearing an “on-year” crop, showed that practically no flowers were produced on fruit-bearing wood. The few inflorescences that were recorded on fruit-bearing wood tended to be of the leafless types.

It is suggested that the cause of biennial bearing in sweet orange is the diffusion of a flower inhibitor, possibly a gibberellin-like substance, from the fruit into the wood on which it is borne.  相似文献   

8.
Fertilizer nitrogen was applied to pot-grown trees during the year of initial scion growth either as “spring N”, “summer N” or “autumn N”, while other trees were left untreated—“minus N”. Tree performance was followed until fruit set the following summer.

At regular intervals whole trees were sampled, divided into as many as seven different parts, which were separately weighed, dried and analysed for total nitrogen. Specimens were also taken for histological examination of flower bud development.

The large amount of fertilizer given as “spring N” resulted in extensive root damage from which the trees did not recover fully; nevertheless they produced large, vigorous scions. After “spring N” and “summer N” at lower dosages the total N content of all parts increased substantially and rapidly. “Autumn N” was absorbed more slowly and remained largely in the roots during the winter, when a considerable amount of root growth took place.

Flowers were initiated in late July or early August on all trees except those given “spring N”, on which flower primordia were not initiated until September. The development of flower buds was accelerated during September on “summer N” trees compared with those left untreated. From the end of November until the end of March no further differentiation took place on “minus N” or “spring N” trees, but it continued on the other treatments, especially following “autumn N”.

“Summer N” and “autumn N” trees were 4–5 days in advance of the others in flowering. “Summer N” trees had large flowers and large green primary leaves, whereas those on “autumn N” trees were smaller and the leaves were initially pale, though turning dark green during blossoming.

When the blossoms were self-pollinated under controlled conditions virtually no fruit was set on “minus N” and “spring N” trees, but “summer N” gave an appreciable set and “autumn N” a heavy set. Only the “summer N” and ”autumn N” flowers had ovules that remained viable six days after anthesis, which was the minimum period found necessary for the pollen tubes to effect fertilization.

It is suggested that fertilizer nitrogen stimulates the synthesis of a kinin-like factor in the roots and that the difference in response to applications at different times of year depends upon the stage of development of the flower buds when this factor reaches them.  相似文献   

9.
Context

Global pollinator decline has motivated much research to understand the underlying mechanisms. Among the multiple pressures threatening pollinators, habitat loss has been suggested as a key-contributing factor. While habitat destruction is often associated with immediate negative impacts, pollinators can also exhibit delayed responses over time.

Objectives

We used a trait-based approach to investigate how past and current land use at both local and landscape levels impact plant and wild bee communities in grasslands through a functional lens.

Methods

We measured flower and bee morphological traits that mediate plant–bee trophic linkage in 66 grasslands. Using an extensive database of 20 years of land-use records, we tested the legacy effects of the landscape-level conversion of grassland to crop on flower and bee trait diversity.

Results

Land-use history was a strong driver of flower and bee trait diversity in grasslands. Particularly, bee trait diversity was lower in landscapes where much of the land was converted from grassland to crop long ago. Bee trait diversity was also strongly driven by plant trait diversity computed with flower traits. However, this relationship was not observed in landscapes with a long history of grassland-to-crop conversion. The effects of land-use history on bee communities were as strong as those of current land use, such as grassland or mass-flowering crop cover in the landscape.

Conclusions

Habitat loss that occurred long ago in agricultural landscapes alters the relationship between plants and bees over time. The retention of permanent grassland sanctuaries within intensive agricultural landscapes can offset bee decline.

  相似文献   

10.
《Scientia Horticulturae》2004,102(1):37-52
Farmers in Phrao, north Thailand, have often, on a “trial-and-error” basis, planted mango (Mangifera indica L.) in orchards composed of mango, lychee (Litchi chinensis Sonn.) and longan (Dimocarpus longan Loureiro). This met with varying success. In 1993, a comparative performance analysis (CPA) of 45 orchards containing mango was done to identify land and management aspects that condition the level of the mango productivity. The orchards were often situated on podzolic soils on hills, footslopes, and terraces that dry out deeply during the dry season. Yields were expressed in farm-gate prices since middlemen purchased the produce from farmers “on the tree”. With many orchards having “low” yields and 18 having “0” yield, the yield data had a loglinear distribution. Using data from all sites, a final model that estimates Ln(yield+1) was derived; it quantifies contributions to the total yield gap for each identified specific yield constraint. It suggests that yields increased if: (i) it was not an “off” year (caused by the biennial bearing behaviour of mango; use of growth regulators may remedy this); (ii) the orchard was situated on a hill or on soils with a relatively high pH or poor water holding capacity (mostly shallow soils with SCL topsoil; water stress causes crop dormancy and induces flower initiation); (iii) the possibility existed to apply supplemental irrigation water (orchards having a growth flush or in a fruit bearing stage require adequate water management possibly including supplemental irrigation); (iv) in established orchards weeding by tractor was practised (this causes root pruning that affects the trees physiological cycle); (v) pruning was practised (this was normally done to remove branches damaged by stem boring caterpillars, all orchards suffered from this serious problem); (vi) spraying by motor sprayer was done that dispenses pesticides, preferably Azodrin (monocrotophos), deep into the canopy. Based on data covering one production season only, the model suggests that environmental factors (location and pH) account for some 30% of the yield gap defined by the difference of the average production situation with the anticipated best one, that management factors account for 49% and the year effect (species attribute) for 21%. Management of mango orchards requires use of up-to-date technology since responses provide exponential returns. It not only demands that farmers are knowledgeable and experienced but also that a well-informed extension service collaborates closely with researchers.  相似文献   

11.
Summary

Potted M.26 apple (Mahis domestica) liners were treated with the gibberellin biosynthesis inhibitor prohexadione-Ca (Apogee®) at 0 to 500 mg l”1 as a foliar spray. Apogee inhibited stem elongation, leaf formation, total leaf area and shoot dry weight, while significantly increasing specific leaf weight, root dry weight and root: shoot ratio, regardless of rate. Foliar application of gibberellin A4+7 (GA4+7) at 200 mg l”1 to Apogee-treated plants one day later reversed these effects, especially stem elongation, root dry-matter production and root: shoot ratio. Apogee increased N concentration in stems but not in leaves and roots. There was no effect on the pattern of N allocation amongst organs. GA4+7 increased leaf N concentration but decreased stem and root N concentrations compared with untreated controls, with N allocation shifting from roots to stem. Total nonstructural carbohydrates (TNC), expressed either on a concentration or content basis, increased in all parts of the Apogee-treated plants, due to increased levels of starch rather than soluble sugars, without altering allocation pattern. Conversely, GA4+7 reduced TNC levels (mainly starch levels) in all parts, with the pattern of allocation slightly shifted from roots to stem. The afternoon decline in stomatal conductance occurred earlier in the Apogee treated plants, measured 10 d after stem elongation had ceased. Starch buildup in the Apogee-treated plants appeared to be associated with this effect, suggesting an involvement of a feedback inhibition of photosynthesis in the Apogee-induced stomatal control.  相似文献   

12.
番石榴成花习性的调查   总被引：2，自引：0，他引：2  
 调查了番石榴( Psidium guajava L. ) ‘新世纪’、‘无核’和‘水晶’品种的成花特点, 结果发现, 着生花蕾的第2～4 节叶片处枝梢的直径明显大于其他叶位处枝梢的直径, 而且淀粉和可溶性糖的含量高于其他节位枝梢。  相似文献   

13.
Summary

An experiment on Regulated Deficit Irrigation (RDI) was performed during 1995 and 1996 in an orchard planted with drip-irrigated ‘Clementina de Nules’/Carrizo Citrange in Moncada (Valencia) Spain. Treatments consisted of a control, irrigated during the whole year at 125% ETlys and RDI treatments where irrigation was reduced to 25% or to 50% of crop evapotranspiration measured by a weighing lysimeter (ETlys) during one of the following periods: I) flowering and fruit set (spring); II) initial fruit enlargement phase (summer) and III) final fruit growth and maturation phases (end of summer-autumn). An additional treatment, denominated 50%-Year, was irrigated at 50% ETlys during the whole year. The effects of RDI treatments in relation to tree water status (pre-dawn Ψpd and midday Ψmd leaf water potential, as well as their integral with time) show a good relation between total shoot emergence in the different growth flushes and the stress intensity reached (Ψpd) (r2 = 0.80). This correlation was mainly due to the number of floral shoots (r2 = 0.86) and not to vegetative ones (r2 = 0.22). Similar results were observed between the stress integral at pre-dawn in each period and the former sprouting variables. In all cases, correlation was better with pre-dawn leaf water potential or with pre-dawn stress integral than with those at midday. RDI during spring reduced shoot length of the first growth flush (A1) and increased fruitlet fall after restarting normal irrigation. It also produced “off-season” flowering in the second flush growth (A2) and increased shoot emergence of the third flush growth (A3) with about 10% of them being floral. Summer RDI treatments did not alter vegetative growth, and although they produced off-season flowering (A3) it was much smaller than that of autumn RDI treatments, which in addition reduced vegetative growth with respect to the control. These effects, together with those of yield and fruit quality presented elsewhere, show that summer is the more appropriate period to apply RDI in “Clementina de Nules” mandarin trees.  相似文献   

14.
The effects of shading on lisianthus (Eustoma grandiflorum) floral transition, plant development, flower yield and quality, and content of starch and soluble sugars were assessed in three cultivars, over two consecutive years. Shading nets affording 67% or 88% reduction in light intensity, were fitted at planting in the greenhouse for periods ranging from 3 to 8 weeks. Meristem morphology at floral transition was characterized by apical meristem widening and the appearance of two bract primordia. Floral transition time was affected by cultivars, but in general, longer and heavier shade treatments delayed floral transition; the longest delay (6 weeks) being recorded in Mariachi White under 88% shade for 7 weeks or under a combined shade treatment of 88% for 3 weeks followed by 67% for 5 weeks. Despite interactions between cultivar and shade treatment, consistent trends were discerned: the heaviest and most prolonged shading reduced yield (up to 40%), cut stem length (up to 15%), and number of flower buds/stem (up to 26%), within cultivar. Total carbohydrates levels were very low, and it is questionable whether changes observed in carbohydrate quantity following shade treatments had any effect on plant growth or flower yield. Rather, it appears that lisianthus is very dependent on current photosynthesis, so that even a brief shading interlude could reduce branching and flower quality. It may be concluded that the intensive shading usually applied is detrimental for lisianthus.  相似文献   

15.
不同贮藏温度下兰州百合种球淀粉代谢与萌发关系初探   总被引：36，自引：5，他引：36  
 不同的贮藏温度和贮藏时间，兰州百合鳞茎碳水化合物含量均有显著差异。顶芽6℃处理的淀粉含量最高，10℃处理最低；鳞茎盘的淀粉含量与之相反；鳞片的淀粉含量随着贮藏温度的降低而下降。鳞茎各部位可溶性糖的含量以及顶芽和鳞片的淀粉酶活性随着贮藏温度的升高而降低，鳞茎盘的淀粉酶活性为6℃处理最高，2℃处理最低。淀粉含量和淀粉酶活性呈极显著负相关。贮藏初期的34 d，顶芽在鳞茎内迅速发育，鳞茎内物质变化最活跃：淀粉含量明显下降，淀粉酶活性迅速增大，可溶性糖含量显著升高。顶芽和鳞茎盘的变化幅度大于鳞片，外部鳞片的变化幅度大于中部和内部鳞片。贮藏温度与贮藏时间之间的显著互作影响碳水化合物的代谢及鳞茎的萌发。在本试验中，2℃贮藏101 d为解除休眠的最佳处理。  相似文献   

16.
The growth pattern of 20 cultivars of pineapple (Ananas comosus (L.) Merr.), with particular reference to propagules differentiation, was studied under uniform, natural conditions over a period of 3 years. The propagules, depending on cultivar, were “suckers” (arising from below the soil, rooted), “shoots” (arising between the leaves), “hapas” (arising from the peduncle-base) and “slips” (arising at the base of the fruits). A few cultivars produced no slips or only a limited number of slips. In addition to the normal adaxial slips, abaxial slips were sometimes formed. “Crown slips” (arising at the top of the fruit) were occasionally encountered. Regular hapas production was confined to 2 cultivars. Marked variation existed in the pattern of shoot formation. Whereas in the majority of plants, shoots were found at regular intervals along the stem, in 2 cultivars the shoots grew as whorls at the base of the stem. Suckers were produced by all cultivars, with one prominent exception. The crown was most often single, but occasionally multiple and fasciated. Whereas bolting almost invariably preceded inflorescence emergence, in a few cases bolting was not followed by flower formation. The inflorescences of 2 cultivars constituted an exception in not having normal types of pigmentation. There were cultivar differences in the number of florets in an inflorescence. Many of the cultivars showed a distinct tendency for photoperiodic sensitivity.  相似文献   

17.
石竹试管花的诱导及其影响因子的研究   总被引：15，自引：3，他引：12  
以石竹试管花的茎段为材料，研究了几种因子对试管花形成的作用。结果表明，开花植株的茎段可稳定地保持形成花芽的能力；外源激素对试管花的形成不是必需的因子。低浓度的生长素利于长根，对花芽的形成没有明显的影响，但较高浓度明显地抑制试管花的形成；细胞分裂素只促进营养芽的分化，完全抑制花芽的形成；所试培养基的各类和浓度除Ｎ６培养基外对花芽的作用没明显的差异；在缺ＮＨ４ＮＯ３的培养基中植株的营养生长受到抑制，植株变矮，叶片数减少，基部叶片发黄，植株提前开花，但不影响开花率。植株上部茎段比下部茎段形成花芽的频率高。  相似文献   

18.
Summary

Endogenous GAs have been suggested as regulators of stem elongation and flowering of cold-requiring plants. Here, the relationship between temperature conditions and responsiveness to GA4 on stem elongation and flowering of stock (Matthiola incana) was investigated. The optimum temperature for induction of flower bud initiation was 10°C, and the minimum duration was 20 d in the late flowering cv. Banrei; the type of cold treatment effect on flowering was classified as a “direct effect”. Stem elongation was markedly promoted by cold treatment regardless of flower bud initiation. The cold treatment amplified the stem elongation response to GA4. The GA4 level necessary for flower bud initiation was lower in the 10°C treatment than in the 15°C treatment, and it became lower at longer durations of cold treatment. These results indicate that the cold treatments enhance responsiveness to GA4 not only in the stem elongation process but also in the flower bud initiation process and that the development of responsiveness to GA4 may correlate with the temperature and duration of cold treatment.  相似文献   

19.
Summary

Trees of peach cvs Flordastar, Flordaprince, Flordacrest and Maravilha, low in chill requirement (Flordaprince 150; Flordacrest 350 C.U.), with a short fruit development period (Flordaprince 90; Flordacrest 110 d) and a very early ripening time (Flordastar mid May; Flordacrest first week of June), were planted in Sicily (37° 30′ Lat. N) both in a medium (667 trees per ha) and a high density (2000 trees per ha) plantation system. In the medium density planting system, the trees were trained to a Fusetto, and in the high density to a Y-shape. Both in the Fusetto and Y, the size of the trees was controlled by severe pruning soon after harvest, consisting in the shortening of most of the one year old wood. From mid June to October, the trees of all four cultivars were able to recover a “fruiting canopy”; flower bud density, flower fertility, fruit set, fruit quality and crop efficiency were not affected by the severe summer pruning. Due to the planting density and the pruning, the tree growth was restricted: no platforms or ladders were required to perform the cultivation techniques at the top of the Fusetto nor was the wire-trellis necessary to sustain the Y-shaped trees. To distinguish these training systems from the original ones, Fusetto and Tatura trellis, we called them “dwarfed Fusetto” (dF) and “free standing Tatura” (fsT), respectively. Although production per tree was higher in the dF, due to planting density fsT yielded more per hectare.  相似文献   

20.
The effect of plant age, temperature and day-length on flower initiation and development in “ K. & M. Super ” freesias has been studied.

The flowering response decreased with increasing temperature and the critical temperature for flower initiation was found to be about 21°C. An interaction of plant age, temperature, and duration of treatment was present. Short days (9 hrs.) slightly stimulated flower initiation in“ Yellow K. & M. Super” but delayed it in “ Blue K. & M. Super” freesias. Short-day treatment in the open during the summer had no significant effect, whereas shading markedly hastened flowering.

Flowering could be initiated at an early stage, but older plants were more responsive, especially those of “Blue K. & M. Super”. Optimum temperatures for flower initiation were 12-15°C., applied for 6-9 weeks after the plants had formed about seven visible leaves.

Abnormal inflorescences in freesias, recognized by enlarged bracts and irregular spacing of the florets (so-called “gladiolus-like flowers”), appeared to result from incomplete flower initiation. In extreme cases flower stalks without any flowers were formed. In order to avoid such abnormal flowering it was important that the first floret in the inflorescence should have reached a certain stage (P2) of development before low-temperature treatment was discontinued.  相似文献   

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