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1.
Elevated temperatures associated with climate change result in crops being exposed to frequent spells of heat stress. Heat stress results in reduced yield in field pea (Pisum sativum L.); it is therefore important to identify cultivars with improved pod and seed retention under heat to mitigate this loss. Objectives were to investigate the effect of heat stress on phenology, yield and pod-based yield components. Sixteen pea cultivars were evaluated at normal and late (hot) seeding dates in the field in Arizona 2012 and in growth chambers with two temperature regimes (24/18°C and 35/18°C day/night temperature for 7 days) during reproductive development. We measured variation in the pattern of pod retention at four-node positions on plants, seed retention by ovule position (stylar, medial and basal) within pods and screened cultivars for pod retention, seed retention and yield. Heat stress reduced seed yield by accelerating the crop lifecycle and reducing pod number and seed size. Heat stress had the most damaging effect on younger reproductive growth (flowers and pods developed later), resulting in ovary abortion from developing flowers. Heat also accelerated seed abortion in all ovule positions within pods. Two high-yielding cultivars under control temperature, “Naparnyk” and “CDC Meadow”, maintained high yield in heat, and “MFR043” had the lowest yield. Cultivars “40-10” and “Naparnyk” retained the most ovules and seeds per pod, and “MFR043” aborted seeds when exposed to heat. In half of the cultivars, ovules at the basal peduncle end of pods were likely to abort while ovules at the medial and stylar end positions developed into seeds. For seven of the field cultivars, ovules at the medial pod position also produced mature seeds. Cultivars “40-10”, “Naparnyk” and “CDC Meadow” had greater pod and ovule retention or maintained high yield under heat stress, and were identified as heat-tolerant cultivars. Our results allow for a better understanding of pod-based yield components in field pea under heat stress and developing heat-tolerant cultivars.  相似文献   

2.
本研究将通过低温(3℃~5℃)干燥处理花椰菜完全开放的花和不同大小的蕾,利用花粉活力测定、花粉萌发观察和杂交结籽率检测等手段分析了低温保存对其花粉活力及授粉效果的影响。研究结果表明,当天开放花的花粉活力和萌发率最高,分别达到91.3%和45.6%,授粉效果也最好,每角果平均可收获11.3粒种子。3℃~5℃干燥储存8 d后花粉活力和萌发率显著降低,储存16 d后花粉杂交结籽率显著降低,不适合作为花粉供体;开花前1 d和2 d的蕾,3℃~5℃干燥储存8 d的花粉活力分别为88.3%和85.2%,萌发率均为32.4%左右,授粉杂交结籽率分别达到9.8和8.3粒种子/角果。随着储存时间的延长,花粉活力及萌发率逐渐降低。3℃~5℃干燥储存32 d的花粉杂交结籽率仍可达到8粒种子/角果。本研究结果为花椰菜杂交一代制种和组合测配的花粉保存提供理论依据。  相似文献   

3.
Knowledge about the degree of spontaneous outcrossing of diverse genotypes is essential for breeding programmes, maintenance breeding, and seed production. For tomato (Lycopersicon esculentum Mill.), very limited scientific evidence for genotypic differences is available and evidence from Europe is scarce. To close this knowledge gap, six cultivars were investigated in three Central European locations as part of the Organic Outdoor Tomato Project. To determine outcrossing rates, the monogenetic “cut‐leaf” trait, which is dominant over the “potato‐leaf” trait, was used as morphological marker. The observed range of outcrossing was 0.0%–5.2%. Outcrossing was significantly influenced by cultivar and environment. The outcrossing rate of individual flowers varied within cultivars ranging from 0% to 37%. The potential of newly opened flowers to accept foreign pollen varied largely with the cultivar. Genotypic differences could partly be linked to flower morphology traits. The potential for recombination between tomato genotypes is generally very low but can be a source for new variation in on‐farm management.  相似文献   

4.
通过对24个菜用大豆品种花荚及籽粒形成的比较,认为不同熟期类型品种间发育规律存在差异。早熟品种较晚熟品种花、荚形成发育快,时间短,脱落也快。籽粒形成主要集中在三个时期：籽粒重在中后期,荚皮重在中前期,荚重在中期。中期的生殖生长是籽粒形成的基础,也是影响产量的关键。因此在江苏徐淮地区的生态条件下,鼓粒前的花荚期长短是选择菜用大豆品种生育指标的重要因素。菜用大豆鼓粒前的花荚期以20d左右为宜。  相似文献   

5.
The present study aimed at studying the effect of boron on pollen characteristics, translocation of water soluble sugars and its importance as a specific nutrient for seed production in lucerne. Aquous solutions of borax (0, 2500, 5000, 7500, 10 000 and 20 000 ppm) were sprayed at flowering stage. After 20 days, the fresh flowers were collected from the plants of all the treatments separately. The pollen was dusted on glass slides containing Muntzing's mixture for staining. After 6 hours, the data on pollen size, stainability and germination were recorded in 10 randomly selected microscopic fields. The estimation of water soluble sugars and boron content in flowers was done by standard methods. Data on grains per pod, grains per inflorescence and 1000 seed weight were recorded at seed maturity. With increasing rates of applied B, pollen germination, water soluble sugars, boron content and number of seeds per pod and per inflorescence increased but pollen fertility decreased. The pollen size and 1000 seed weight was not affected by boron concentrations. The results indicate that boron plays a definite role in increasing the seed yields through stimulating the physiological processes during reproductive phase.  相似文献   

6.
The efficacy of a synthetic detergent (Surf Excel) as a potential chemical hybridizing agent in Brassica juncea was studied. Foliar sprays with various concentrations of the detergent caused reductions in plant height, number of branches and leaves per plant, size of leaves, anther size, pollen per flower, ovules per flower, pollen fertility, fruits per plant, fruit size, seeds per fruit, total yield per plant and 100 seed weight as compared with those of untreated plants. The style in the floral buds of plants sprayed with different concentrations of Surf Excel elongated and so the receptive stigma protruded from the buds which facilitated cross‐pollination by honey bees. The plants sprayed once with 2% Surf Excel exhibited an elongated style with a raised receptive stigma and 100% pollen sterility without causing a significant reduction in total yield.  相似文献   

7.
Experiments were conducted over 2 years to quantify the response of faba bean (Vicia faba L.) to heat stress. Potted winter faba bean plants (cv. Wizard) were exposed to temperature treatments (18/10; 22/14; 26/18; 30/22; 34/26 °C day/night) for 5 days during floral development and anthesis. Developmental stages of all flowers were scored prior to stress, plants were grown in exclusion from insect pollinators to prevent pollen movement between flowers, and yield was harvested at an individual pod scale, enabling effects of heat stress to be investigated at a high resolution. Susceptibility to stress differed between floral stages; flowers were most affected during initial green‐bud stages. Yield and pollen germination of flowers present before stress showed threshold relationships to stress, with lethal temperatures (t50) ?28 °C and ~32 °C, while whole plant yield showed a linear negative relationship to stress with high plasticity in yield allocation, such that yield lost at lower nodes was partially compensated at higher nodal positions. Faba bean has many beneficial attributes for sustainable modern cropping systems but these results suggest that yield will be limited by projected climate change, necessitating the development of heat tolerant cultivars, or improved resilience by other mechanisms such as earlier flowering times.  相似文献   

8.
Summary The development and timing of different processes in the floral biology and sexual reproduction of Lilium longiflorum were studied and brought together into a chronological reproductive calendar. Care must be taken when emasculating flowers later than 4 days before anthesis (DBA), because the stomium of the anther was open from 8 DBA and the pollen grains appear to be mature from 3–2 DBA. The receptivity period of the pistil lasts for a rather long period, but before wilting of an unpollinated flower as determined by a change of the colour of the perianth from white into brown, the flower had already lost its receptivity. Because L. longiflorum pollen grains can easily be stored, the pistil receptivity should thus determine the pollination schedule. The relationships between pollen tubes and pistil are discussed with respect to plant breeding.Abbreviations DAA Days After Anthesis - DAP Days After Pollination - DBA Days Before Anthesis  相似文献   

9.
When the flowers are not disturbed, the yield of F1 hybrids of faba beans normally exceeds that in their inbred parents. The basis of this “heterotic autofertility” was investigated by examining flowers for pollination and fertilization throughout the flowering season and assessing the distribution of seeds and pods on mature plants. Six inbred lines and seven of their F1 hybrids were grown without protection from bee visitation, and their autofertility was estimated’ by comparing their fertilization with that of cytoplasmic male-sterile line. The first direct evidence was obtained that heterotic autofertility acts by increasing; the proportion of flowers which were pollinated and fertilized. The autofertility was not perfect, especially in a closed-flower hybrid, as many ovules remained unfertilized. Several factors contributed to the number of seeds per pod in F1 hybrids, being superior to parental means: (1) more ovules per flower, (2) greater fertilization of the basal ovules, (3) reduced abortion of the apical ovules and (4) greater overall maturation ovules.  相似文献   

10.
Flowering, Pod Set and Reproductive Success in Soya Bean   总被引：2，自引：0，他引：2  
Much of the variation in yield of soya bean [Glycine max (L.) Merrill] and other grain crops is associated with changes in the number of pods and seeds per unit area. Photosynthesis and seed characteristics are the primary determinants of pod and seed number, but recent research suggests that the temporal distribution of flower production may also play an important role. Soya bean has a long flowering period (up to 40 days or more), but most of the flowers are produced in a much shorter time. The length of the period varies among cultivars, growth habits (indeterminate and determinate) and environments. The reproductive success of flowers produced early in the period is usually greater than those produced later. Little is known, however, of the regulation of the temporal distribution of flower production or its potential role in determining pod and seed number at maturity. Research is needed to determine first, if the temporal distribution can be manipulated to increase pod and seed set and secondly, if such increases would result in higher yields.  相似文献   

11.
Two experiments were conducted under field conditions to evaluate reproductive abscission, seed yield and yield components of three cowpea [Vigna unguiculata (L.) Walp.] genotypes. In the first experiment, level of abscission and yield of two cultivars, California Blackeye Pea No. 5 (CA-5) and Speckle Purple Hull (SPH), and one experimental line (AZ-54) were studied. In the second experiment, effect of drought stress on abscission at three nodal positions, seed yield, and yield components of CA-5 were studied. Abscission in both experiments was determined by counting scars left by dropprd reproductive structures including floral buds, open flowers, and immature pods. Abscission of CA-5 and AZ-54 in the first experiment ranged between 68 and 76 % while that of SPH ranged between 86 and 89 %. CA-5 and AZ-54 retained two to three pods per peduncle, and SPH retained only one mature pod per peduncle. Average seed yields of SPH and AZ-54, respectively, were 45 and 50 % of CA-5. Drought stress in the second experiment did not affect production of floral buds Peduncle?1 (average of 10) but significantly increased percent reproductive abscission and decreased pod retention of CA-5. Abscission in the bottom two-third nodes increased from 82 % in well-irrigated plants to 93 % in non-irrigated plants. This increase in abscission corresponded to nearly 60 % reduction in pod retention. The number of pods per peduncle in the bottom two-third nodes decreased from 1.9 in well-irrigated plants to only. 77 in non-irrigated plants. The increase in abscission and decrease in pod retention with increasing intensity of drought was greatest in the bottom one-third nodes. Drought stress did not affect abscission and pod retention in the top one-third nodes. Stress also decreased peduncles plant?1, seeds pod?1, and dry matter and seed yield plant?1 but did not affect seed weight and harvest index. The decrease in seed yield was largely due to reductions in pods plant?1 and seeds pod?1. The reduction in the number of pods and, therefore, seed yield due to stress was because of reductions in the number of peduncles plant?1 and increases in reproductive abscission. It is concluded external conditions that increase abscission beyond that of normal occurrence affect seed yield adversely.  相似文献   

12.
The tree peony (Paeonia suffruticosa Andr.) is a valuable ornamental plant. American and French cultivars have desirable flower colors, while, Japanese cultivars have larger flowers with better presentation. We hybridized an American tree peony cultivar ‘High Noon (HN)’ (the seed parent) with 57 different Japanese cultivars (pollen parents) to investigate cross compatibility, with the ultimate goal of obtaining improved hybrids. Of the 1,927 crosses performed, 135 (38 cross combinations) yielded a total of 181 seeds (86 mature) and 22 seedlings. Five of the hybrids have already flowered and exhibited their parent character with large yellow flowers. To investigate the causes of cross incompatibility, we examined pollen tube growth in a cross between ‘HN’ and a Japanese cultivar. The result indicated that there are three most important causes of incompatibility, namely, abnormal pollen tube growth, the failure of fertilized ovules, and poor seed germination. Although cross compatibility in each combination was low, crosses between ‘HN’ and Japanese cultivars might be successful with the right paternal plants. In this study, 13 Japanese cultivars had higher cross compatibility with ‘HN’ than the others. Our results will enhance tree peony breeding and guide the selection of parents for hybridization.  相似文献   

13.
Radiant frost is a major abiotic stress, particularly at the reproductive stage, in field pea (Pisum sativum L.) grown in Mediterranean environments. Here, response to frost was studied for flowering stage (FS) organs (buds, flowers and set pods) and pod development stage (PDS) organs (flat, swollen and mature pods) under controlled conditions, with plants exposed to a minimum temperature of –4.8°C for 4 h. This frost treatment adversely affected seed yield through (i) abortion of buds, flowers and set pods (ii) death of pods and (iii) reduction in seed size. FS organs were more sensitive to frost than PDS organs. Genetic variation was observed among 83 accessions collected from 34 countries worldwide for survival of FS buds, flowers and set pods. In 60 of 83 accessions, no buds, flowers or set pods survived the frost treatment. Five accessions: ATC 104 (origin: United Kingdom), ATC 377 (Estonia), ATC 968 (Italy), ATC 3992 (Kazakhstan) and ATC 4204 (China), showed the highest frost tolerance of FS organs and lowest numbers of abnormal seeds. The frost tolerant accessions identified in this study may be useful as parents for breeding field pea varieties that will be less likely to suffer yield loss due to radiant frost during the reproductive stage.  相似文献   

14.
We investigated variation in floral morphology among 36 accessions of radish (Raphanus sativus L.). We found wide, continuous inter-accession variation in 15 traits related to the size of the floral organs and the stigma position relative to the anthers of long stamens. A principal-component analysis of the 15 floral traits also showed wide variation among accessions. A large proportion of this variation was accounted for by lengths of stamens and the petal tube. In addition, the phenotypic stabilities with respect to the macro-environment (as affected by different sowing dates) and the micro-environment (among the flowers within a plant) differed between traits. Correlation analyses using all traits suggest the existence of genetic linkages or pleiotropies among floral organs. Our results indicate that floral morphologies varied greatly among radish accessions and they could be affected by the macro- and micro-environment. To explore the relationship between floral morphology and pollination efficiency, we compared the number of pollen grains deposited on the stigmas in the presence and absence of insect pollinators using three accessions with very different floral morphology. Because an accession with a higher stigma position than anthers might avoid self-pollination and an accession with a large stigma size received more pollen grains, floral morphology may affect pollination efficiency. Because the effect of pollination efficiency on seed production is well known, our results suggest that radish floral morphology affects seed production through its effect on pollination efficiency.  相似文献   

15.
以八仙花“经典红”为试验材料,利用扫描电镜定期观察花芽形态发育进程,在花芽分化后期将植物进行控温促花处理,观察其开花情况,分析温度对八仙花成花的影响。结果表明,八仙花的花芽分化过程分为5个阶段,分别是营养生长期、花芽膨大期、分生组织分化期、花原基形成期以及花器官形成期；经过不同时间低温处理的八仙花均能提前开花,但未经过低温春化的植物,花品质受到一定的影响；八仙花花芽分化与温度具有显著相关性,20-25℃开始生长点膨大,15-20℃进入分生组织分化期,10℃形成花原基,5℃形成花器官并打破休眠,整个过程历时约4个月。  相似文献   

16.
We investigated heat tolerance at the reproductive stage in six spring‐type B. rapa accessions and one B. juncea accession as a control. Plants were subjected to two temperature treatments for seven days in controlled environmental rooms, beginning one day before the first open flower on the main stem inflorescence. The high‐temperature treatment ranged from 25 °C to 35 °C during 16 h light and 25 °C during 8 h dark. The control temperature treatment was set at 23 °C during 16 h light and 15 °C during 8 h dark. Soil moisture was maintained at close to field capacity to avoid drought stress. Main stem buds that emerged during the treatment period were tagged, and pod and seed production was recorded at each reproductive node. Leaf temperature depression and leaf conductance increased in the high‐temperature treatment which indicated that plants were not drought stressed. A leafy vegetable type of B. rapa from Indonesia was the most tolerant to high temperature, as defined by its ability to set seed equally well in the control and high‐temperature treatments, followed by an oilseed type from Pakistan. Pollen viability remained above 87 % in all accessions and treatments. We conclude that bud number and length, and pod number produced under high temperatures, might provide a useful preliminary screen for high‐temperature tolerance and that B. rapa may be a valuable source of heat tolerance in canola (B. napus).  相似文献   

17.
厚轴茶雄性不育株花药败育的生物学特性和细胞学研究   总被引：1，自引：0，他引：1  
为明确厚轴茶(Camellia crassocolumnaH. T. Chang)雄性不育株花器发育形态、花药和花粉败育时期及兵细胞学特征,利用体视显微镜、石蜡切片技术、染色体制片和DAPI染色法,对厚轴茶雄性不育株和可育株开花迚程、花器形态、花药发育过程、花粉母细胞减数分裂及小孢子发育过程比较观察。结果显示,厚轴茶花属于完全花,花药其四室、呈蝶形,花药壁发育为基本型,绒毡层细胞其双核,于四分体时期形成分泌型细胞,单核花粉期开始降解,花粉母细胞经过减数分裂Ⅰ、减数分裂Ⅱ和胞质分裂后形成四面体型四分体,小孢子呈三角形,成熟花粉为二细胞型花粉。花蕾发育早期,不育株雄蕊发育正常,与可育株无明显差异。花蕾发育后期,不育株花丝弯曲,花药粘连、干瘪、褐化、坏死,不裂药。不育株减数分裂期绒毡层细胞异常增生、排列混乱,单核至双核花粉期绒毡层延迟降解。不育株花粉母细胞减数分裂过程中存在环状单价体、滞后染色体、染色体桥、染色体缺失、不均等分离、微核和多分体等异常现象。不育株小孢子胞质紊乱,单核期花粉粒相互粘附,花粉壁皱缩变形,花粉细胞质和细胞核模糊不清,成熟花粉细胞空瘪凹陷。研究结果表明,厚轴茶雄性不育花器形态属雄蕊萎缩型和花药异常型,花药发育受阻于减数分裂至单核花粉期,存在花粉母细胞败育型和单核败育型。单核花粉期是兵花药败育的主要时期。花药绒毡层异常发育和延迟降解,花粉母细胞减数分裂染色体行为异常,小孢子和花粉粒发育异常可能是兵花药败育的主要原因。  相似文献   

18.
Pear and apple are among the main fruit crops worldwide. These species can be planted in mixed orchards, and they both depend on insect pollination for fruit set. As pollinating insects are attracted by the floral resources, we investigated nectar and pollen production and chemical composition in four pear (‘Concorde’, ‘Conférence’, ‘Doyenné du Comice’, ‘Triomphe de Vienne’) and five apple (‘Braeburn’, ‘Golden Reinders’, ‘Jonagored’, ‘Pinova’, ‘Wellant’) cultivars commonly grown in Belgium. We also investigated whether insect flower visitation rate and pollination efficiency are linked to floral resource quantity and quality. The pear cultivars flowered one week before the apple cultivars in early spring, and their flowers were about six times less visited by insects. The visitors foraged more on the pollen of the pear trees and the nectar of the apple trees. Pear flowers produced higher volumes of nectar than apple flowers (1.3–3.2 μl vs. 0.4-0.6 μl), but with lower sugar concentration (9.6%-10.8% vs. 28.3%-36.4%). Pear flowers also produced fewer pollen grains per anther than apple flowers (2425–4937 vs. 3284–7919), but these had higher polypeptide (346–362 μg/mg vs. 216–303 μg/mg), amino-acid (40–77 μg/mg vs. 12–18 μg/mg) and phytosterol (21–47 μg/mg vs. 15–43 μg/mg) concentrations. The foraging behavior of the insects is thus better explained by nectar and pollen quality rather than quantity. Despite the differences in flower visitation rates, pollination of both species resulted in valuable fruit production.  相似文献   

19.
Chickpea (Cicer arietinum L.) has an indeterminate growth nature, and the plant canopy with an improved light environment during critical growth stages may increase biomass (BM) production and improve crop yield. This study examined (i) the effects of shading, light enrichment and defoliation applied at various growth stages on BM and seed yield of chickpea in northern latitudes; and (ii) the difference between cultivars with fern‐ vs. unfoliate‐leaf type in responding to the altered canopy light environments. Field studies were conducted at Saskatoon and Swift Current, Saskatchewan in 2004 and 2005. Different light environments were created by 50 % defoliation at vegetative growth and at first flower, 50 % shading from vegetative growth to first flower, and two light enrichment treatments initiated at the first flower and pod formation stages. The 50 % shade treatment prior to flowering significantly decreased harvest index (HI) and seed yield. Light enrichments increased seed yield only one of three location‐years (the fourth site excluded because of disease damage). Defoliation at vegetative growth or first flower had a marginal effect on seed yield, largely as a result of the regrowth of vegetative tissues compensating for the lost plant tissues. The cultivar CDC Yuma (fern‐leaf type) exhibited consistently greater maximum light interception (LI), cumulative intercepted radiation, HI and seed yield than the cultivar Sanford (unifoliate‐leaf type) across all location‐years. Selective use of chickpea cultivars with improved morphological traits such as fern‐leaf type will likely improve LI and increase crop yield for chickpea in northern latitudes. Moreover, optimized crop management practices should be adopted to ensure that chickpea be grown under conditions with minimum shading before flowering and optimum light environment within the canopy especially during reproductive growth period.  相似文献   

20.
It is not well documented which floral parts may trigger the onset of tepal or petal senescence and or flower bud abscission. Asiatic hybrid (Lilium × elegans Thunb.) ‘Red Carpet’ lily flowers were selected as a model to study this relationship because the various floral organs of a lily flower can be easily dissected and collected for physiological studies. We hypothesized that anther is the organ that triggers flower bud abscission. Ethanol-soluble sucrose, fructose, and glucose were analyzed in the tepal, anther, filament, and pistil. The analysis was conducted on flower buds weighing 1.5 g (small buds) and 3.9 g (large buds). The sucrose content in the anthers of small buds remained high when cut flowers were held at 21 °C for 5 d, suggesting that sucrose is not hydrolyzed into fructose and glucose. However, in large buds, sucrose was not detected when flowers were held at 21 °C for 5 d. The respiration rate of small buds (2.06 g) was high (2000-3000 mg/kg fw) when the tepals were removed and the anther remained attached to the filament, but was low (less than 400 mg/kg fw) in large buds approaching anthesis. Ethylene was produced only in small buds (1.42 g) when the anthers were present. Radioactive 14C sucrose applied to the cut end of the pedicel was translocated rapidly to the anther at harvest, but was not translocated to the anther when abscission was induced by keeping flower buds at 21 °C. Ethylene detected in small flower buds possibly was stimulated by physiological changes resulting from the lack of assimilates available to the anther and the lack of sucrose hydrolysis occurring in the anther. The absence of sucrose hydrolysis in the anther and lack of translocation of sucrose from the filaments to the anther in small buds may be factors that contribute to flower bud abscission in ‘Red Carpet’ lily.  相似文献   

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