Ovule Development and Determination of Seed Number Per Pod in Oilseed Rape (Brassica napus L.)

Seed number per pod at maturity over the terminal raceme ofsingle plants of oilseed rape is closely correlated to the percentageof ovules with complete embryo sacs (ovule fertility) at floweropening. Approximately one-third of the ovules did not containan embryo sac and sterility, due to the absence of embryo sac,accounted for most of the difference between the numbers ofovules and seeds. Within the terminal raceme, both a decreasedproportion of fertile ovules and a lower number of ovules perovary in apical flowers contributed to the lower number of seedsper pod in the mature apical pods compared to the basal ones.A study of ovule development before flower opening showed thatdifferences in the differentiation of the embryo sacs arosebefore the buds were 40 mm long and probably involved the stagesof meiosis II and/or differentiation of the chalazal megaspore. Key words: Oilseed rape, ovule development, seed number per pod     

Patterns of fruit and seed production inBauhinia ungulata (Leguminosae)

Patterns of seed and fruit production ofBauhinia ungulata, a small tree legume indigenous in tropical America, were studied in Costa Rica. Only about 8% of flowers produced fruits. The average pod had 19 ovules and about two thirds of these began seed development, with mature pods containing an average of 9.7 mature undamaged seeds. About half of the mature pods were damaged by herbivores and within these, 27% of ovules or seeds had been eaten. Among trees there was no significant variation in pod production, but the number of ovules per pod and seed production per pod varied significantly. Within infructescences most pods were retained at middle positions. Within pods, the probability of an ovule developing into a seed increased toward the distal end. The pattern of seed and fruit production in this species agrees well in general with that reported for other neotropical legumes. The abortion of seeds and fruits can be regarded as a way of controlling maternal investment, and as a response to herbivory.     

Density Studies on Lupins. II. Components of Seed Yield

Components of seed yield of cv. Ultra (Lupinus albus L.) andcv. Unicrop (L. angustifolius L.) were measured when grown atthree densities. The low density (10 plants m^–2) Unicropyield (34 g seed per plant) was 1.8 times that of Ultra as ithad more branches, pods and seeds per pod. Ultra seeds (310mg per seed) were heavier than Unicrop seeds (180 mg). The branchingpattern of Ultra was less dependent on plant density, henceat 93 plants m^–2 it gave a higher per plant yield (7.4vs 6.4 g) than Unicrop at lower densities (83 plants m^–2).Density had most influence on pod formation and only small effectson seeds per pod and seed weight. Yield components on the main-steminflorescence were influenced less by density than componentson branch inflorescences. Later formed, higher order generationsof inflorescences were most affected by increased inter- andintra-plant competition. Pod numbers on the main-stem were similarfor both species. Pods formed at higher flower nodes in Unicrop,but the lower flower nodes were less fertile than those in Ultra.Node position of flowers had no influence on seed set in main-stemUnicrop pods, but pods from higher nodes in Ultra formed fewerseeds. Seed weights in Unicrop were similar among main-stemnodes but in Ultra seed weights tended to increase at highernodes. Lupinus spp, lupins, seed yield, planting density     

Effects of Phosphorus Nutrition and Light Intensity on Growth and Development of the Cowpea (Vigna unguiculata L.)

The vegetative growth and fruiting of two cowpea cultivars,Adzuki and Early Ramshorn, were studied in controlled environmentexperiments, using two light intensities and three P levelsin sand and in soil media. The higher light intensity reducedplant height, but improved plant growth in terms of increasedbranching, leaf area, plant size and seed yield. High lightintensity delayed flowering, but increased blossom and pod numbers. Increasing levels of applied P enhanced growth, blossom andfruit numbers, as well as leaf numbers and area and earlinessof flowering. Generally, Early Ramshorn plants grew faster andproduced heavier seeds than Adzuki plants, especially at highP. However, Adzuki plants produced greater numbers of flowers,pods and seeds than did Early Ramshorn plants. Under high lightintensity, Adzuki produced the greatest number of seeds at theintermediate P level in sand culture, and this number was greaterthan that produced by Early Ramshorn at the highest P level. In Adzuki, P nutrition did not markedly modify the adverse effectof low light intensity on pod set and mature pod number, anindication of a lower external P requirement and/or higher efficiencyof P utilization than in Early Ramshorn. Phosphorous generallyincreased growth rate and yield and could thus be used to offsetsome of the adverse effects of low light intensity especiallyon Early Ramshorn as well as to hasten growth and maturation.The results obtained with soil culture were similar to thosewith sand culture.     

Comparisons of Earlier- and Later-formed Pods of Chickpeas (Cicer arietinum L.)

In chickpeas (Cicer arietinum L.) flowering and pod developmentproceed acropetally. In plants grown under normal field conditionsat Hyderabad, in peninsular India, and at Hissar in north India,at successively apical nodes of the branches there was a declinein pod number per node, weight per pod, seed number per podand/or weight per seed. The percentage of nitrogen in the seedswas the same in earlier and later-formed pods at Hyderabad;at Hissar the later-formed seeds contained a higher percentage.Earlier- and later-formed flowers contained similar numbersof ovules. The decline in seed number and/or weight per seedin the later-formed pods of 28 out of 29 cultivars indicatedthat pod-filling was limited by the supply of assimilates orother nutrients. By contrast, in one exceptionally small-seededcultivar there was no decline in the number or weight of seedsin later-formed pods, indicating that yield was limited by ‘sink’size. Cicer arietinum L., chickpea, flowering, pod development, seed number, seed weight, nitrogen content     

Expression of the narrow leaflet gene for yield and agronomic traits in soybean

Genes that affect plant form and function may be used to enhance the yield of soybean [Glycine max (L.) Merr.]. Most soybean cultivars have broad (ovate) leaflets. A single gene, ln, controls inheritance for the narrow leaflet characteristic. Narrow leaflet cultivars (ln/ln) also tend to have a higher percentage of four-seeded pods than ovate (Ln/Ln) leaflet cultivars. Heterozygous (Ln/ln) plants have a leaflet shape intermediate between narrow and ovate. Determining the agronomic effects of the narrow leaflet allele (ln) in the heterozygous (Ln/ln) condition in soybean may have applications in practical plant breeding. We studied an ovate leaflet and a narrow leaflet cultivar, crosses between them in the F(1) and F(2), and backcrosses to both cultivars. The ratio of leaflet width to leaflet length accurately distinguished among narrow, ovate, and intermediate leaflet plants in the F(2) and backcross generations. In the F(2) generation, differences occurred among plants with different leaflet morphology. Narrow leaflet plants produced more seeds per pod and lower seed weight than ovate leaflet plants. Narrow and ovate leaflet plants produced comparable numbers of pods per plant and plant yield. Compared to ovate leaflet plants, intermediate leaflet plants produced similar numbers of seeds per pod and seed weight. Intermediate leaflet plants produced significantly more pods per plant and plant yield than plants with either ovate or narrow leaflets. The heterozygous condition at the locus for leaflet morphology resulted in heterosis for plant yield and may be of benefit in association with commercialization and development of hybrid soybean.     

Does successful ovule development depend on its position within the pod? Examples from Neotropical Fabaceae

Previous studies have shown a nonrandom pattern of ovule fate probabilities according to ovule position in legume pods. Here, we tested how ovule position within the pods of two Fabaceae affects its fate. We expected higher proportion of well‐formed seeds near the fruit tips and of unfertilized and aborted ovules near fruit bases. We collected pods of Poincianella pyramidalis and Anandenanthera colubrina in a seasonal dry forest in northeastern Brazil and recorded total pod length and ovule number, position, and fate (unfertilized, well formed, aborted, and predated). The proportion of well‐formed ovules at fruit tips was significantly higher than at fruit bases in P. pyramidalis. The opposite pattern was found for unfertilized and aborted ovules, thus corroborating our hypothesis. However, the probability of seed predation in A. colubrina was significantly higher in pod tips, thus providing moderate support for our hypotheses. Interspecific differences in the patterns of ovule fate are likely to be driven by species pollination systems.     

The effects of flower removal on the seed yield of pigeonpeas (Cajanus cajan)

In field experiments carried out at Hyderabad, India with early and mediumduration cultivars of Cajanus cajan sown at the normal time, in July, removal of all flowers and young pods for up to 5 wk had little or no effect on final yield. The flowering period of the deflowered plants was extended and their senescence delayed. The plants compensated for the loss of earlier-formed flowers by setting pods from later-formed flowers; there was relatively little effect of the deflowering treatments on the number of seeds per pod or weight per seed. The plants were also able to compensate for the repeated removal of all flowers and young pods from alternate nodes by setting more pods at the other nodes.
The removal of flowers from pigeonpeas grown as a winter crop resulted in yield reductions roughly proportional to the length of the deflowering period, probably because maturation of these plants was delayed and occurred under increasingly unfavourable conditions as the weather became hotter.     

EFFECTS OF POLLEN AND RESOURCES ON SEED NUMBER AND OTHER FITNESS COMPONENTS IN AMELANCHIER ARBOREA (ROSACEAE: MALOIDEAE)

Most Amelanchier arborea flowers have 10 ovules, but the number of filled (embryo-containing) seeds per fruit is usually less than 10 and is highly variable within each individual plant. Because fruit developmental time correlates with seed number, this variation in seed number results in asynchronous fruit ripening. Field experiments tested whether seed number was pollen- or resource-limited. Manipulation of resources in the shoot at the time of fruit initiation by defoliation, girdling, fruit thinning, or foliar feeding had no significant effect on seed number per fruit, although fruit set and seed weight were affected. Supplemental cross-pollination also had no demonstrable effect on seed number. Most ovules that do not become filled seeds are visible as small “undeveloped seeds”; these are not necessarily aborted seeds as this was also the fate of ovules in unpollinated carpels. Alternative hypotheses for the determination of seed number are proposed and discussed.     

Injury to oilseed rape caused by mirid bugs (Lygus) (Heteroptera: Miridae) and its effect on seed production

Injury by Lygus spp. to oilseed rape, Brassica napus L. and Brassica campestris L., was assessed based on laboratory and field studies in Alberta, Canada. The visible injuries consisted of lesions on the surfaces of stems, buds, flowers and pods similar to those described for other crops. They caused buds and flowers to abscise and seeds to collapse, and reduced the weight of healthy seeds produced per pod. The plants compensated for bud loss so that no net reduction in the number of pods occurred. However, in some situations the damage to buds resulted in a reduced seed yield that increased with the amount of injury. The plants also compensated for flower loss so that no net reduction in the number of pods occurred, but seed yield declined as injury increased. Plants did not compensate for seeds that collapsed as a result of lygus feeding. The feeding activity of lygus bugs reduced seed yield in oilseed rape.     

Factors affecting the Abscission of Reproductive Organs in Yellow Lupins (Lupinus luteus L.): I. THE EFFECT OF DIFFERENT PATTERNS OF FLOWER REMOVAL

1. The effect of various patterns of flower removal on pod settingwas investigated in Lupinus luteus L. Four-fifths, three-fifths,or two-fifths of the flowers of the main inflorescence wereremoved according to ten different patterns. 2. All flowers could produce pods but later ones were less efficientin doing so. Developing pods had an abscission-inducing effecton later flowers, which became increasingly effective towardsthe apical part of the inflorescence. More pods were retained when flowers on each consecutive whorlwere arranged in a spiral than when the same number was arrangedvertically. Pod setting was incomplete when the number of flowers per inflorescencewas reduced well below the total number of pods normally present. 3. The number of ovules in consecutive flowers gradually decreasedfrom an average of 5.7 at the base to 4.3 at the top of theinflorescence. The ratio of seeds to ovules fluctuated irregularlybetween 65 and 94 per cent, and did not indicate a general trendin embryo abortion. 4. The growth-rate of pods at the top of the inflorescence wasmuch slower than at the bottom. Vascular differentiation wasalmost absent at the top of the inflorescence when the flowerswere fertilized, and further vascular tissue was produced onlywhen flowers produced pods.     

Diversification of seed arrangement induced by ovule rotation and septum formation in Leguminosae

The plants of Leguminosae, which comprises 731 genera, bear monocarpellary flowers. The fruit, known as a pod, generally contains a row of seeds, and the internal structure appears to be simple. In Leguminosae, the seeds are generally arranged longitudinally along the suture of the pod but, in a few genera, namely, Cassia, Indigofera, and Senna, they are arranged transversely. Transverse seed arrangement facilitates the accommodation of a considerable number of seeds and has been considered to be established by rotation of seeds during development. We studied the development both these patterns of seed arrangement, i.e., longitudinal and transverse, in Senna and Indigofera in order to elucidate the structural changes occurring in ovaries (or pods) and determine the forces responsible for rotation of ovules (or seeds) by dissecting ovaries and pods at different developmental stages. Our results showed that at an early developmental stage the ovules were obliquely oriented or transversely arranged; later, the direction of their growth was restricted by the ovary walls or neighboring ovules, and therefore the obliquely oriented ovules rotated inward or outward. Thus, it was clarified that the processes involved in the formation of the internal structure of pods are regulated in a complex manner. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

大豆花荚败育期间的植物激素变化

大豆开花结荚期,不同发育阶段的幼蕾与花荚的脱落率不同,其中以花后5d内的幼荚脱落最严重。与败育花荚相比,正常花荚中的干物质积累量均较高。细胞分裂素(DHZRs,ZRs,iPA)含量也较高,花后3～5d的幼荚中表现更明显。脱落酸(ABA)则是以败育幼蕾及花后3～5d的幼荚中含量较高。不同发育阶段的大豆生殖器官中,正常开放花中的玉米赤霉烯酮(ZEN)含量最高。     

Variation in the Agronomic and Morphological Traits of Iranian Chickpea Accessions

Landraces of chickpea (Cicer arietinum L.) in Iran have not been adequately characterized for their agronomic and morphological traits. Such characterization would be helpful in the development of improved cultivars, so in this study 362 chickpea accessions, collected from the major chickpea growing areas of Iran, were evaluated to determine their phenotypic diversity. High coefficients of variation (CVs)were recorded in pods/branch, seeds/pod, yield/plant, seeds/plant, pods/plant and branches/plant. Using principal component (PC) analysis, the first four PCs with eigenvalues more than 1 contributed 84.10% of the variability among accessions, whereas PC5 to PC10 were less than unity. PC1 was positively related to days to first maturity, days to 50% flowering and days to 50% maturity. The characters with the greatest weight on PC2 were seeds/plant and yield/plant, whereas PC3 was mainly related to pods/plant, seeds/pod and 100-seed weight, and PC4 was positively related to pods/branch and negatively to branches/plant. The germplasm was grouped into four clusters using cluster analysis. Each cluster had some specific characteristics of its own and the cluster I was clearly separated from clusters Ⅱ, Ⅲ and Ⅳ. These accessions are an important resource for the establishment of a core collection of chickpeas in the world.     

Megagametophyte abnormalities of near-isogenic female partial-sterile soybean mutants (Glycine max; Leguminosae)

Megagametogenesis of soybean, Glycine max (L.) Merr., cultivars Clark and Clark k2, and F1 hybrid of Clark (female parent) crossed with Clark k2 (male parent) were studied using stereo light microscopy and confocal scanning laser microscopy. Reproductive development in Clark and Clark k2 plants was compared to F1 hybrid plants. In mature pods, 6.4% of the ovules of Clark, 8.1% of the ovules of Clark k2, and 41.4% of the ovules of F1 hybrid plants were aborted. This female partial sterility was due to incomplete megagametophyte development: undeveloped polar nuclei—or developed but not in a position for fertilization; increased megagametophyte wall thickness; abnormal shape and/or premature degeneration of synergids and intact synergids throughout the life of the ovule; egg cell not well-developed or absent; and megagametophyte remaining uninucleate. Each of these abnormalities contributed to either lack of double fertilization or early megagametophyte abortion. Electronic Publication     

Genetic analyses of agronomic and seed quality traits of synthetic oilseedBrassica napus produced from interspecific hybridization ofB. campestris andB. oleracea

The heritability, the number of segregating genes and the type of gene interaction of nine agronomic traits were analysed based on F₂ populations of synthetic oilseedBrassica napus produced from interspecific hybridization ofB. campestris andB. oleracea through ovary culture. The nine traits—plant height, stem width, number of branches, length of main raceme, number of pods per plant, number of seeds per pod, length of pod, seed weight per plant and 1000-seed weight—had heritabilities of 0.927, 0.215, 0.172, 0.381, 0.360, 0.972, 0.952, 0.516 and 0.987 respectively, while the mean numbers of controlling genes for these characters were 7.4, 10.4, 9.9, 12.9, 11.5, 21.7, 20.5, 19.8 and 6.4 respectively. According to estimated coefficients of skewness and kurtosis of the traits tested, no significant gene interaction was found for plant height, stem width, number of branches, length of main raceme, number of seeds per pod and 1000-seed weight. Seed yield per plant is an important target for oilseed production. In partial correlation analysis, number of pods per plant, number of seeds per pod and 1000-seed weight were positively correlated with seed yield per plant. On the other hand, length of pod was negatively correlated (r = -0.69) with seed yield per plant. Other agronomic characters had no significant correlation to seed yield per plant. In this experiment, the linear regressions of seed yield per plant and other agronomic traits were also analysed. The linear regression equation wasy = 0.074x₈ + 1.819x₉ + 6.72x₁₂ -60.78 (R ² = 0.993), wherex ₈, x₉ and x₁₂ represent number of pods per plant, number of seeds per pod and 1000-seed weight respectively. The experiment also showed that erucic acid and oil contents of seeds from F₂ plants were lower than those of their maternal parents. However, glucosinolate content was higher than that of the maternal plants. As for protein content, similar results were found in the F₂ plants and their maternal parents. It was shown that the four quality traits, i.e. erucic acid, glucosinolate, oil content, and protein content, had heritability values of 0.614, 0.405, 0.153 and 0.680 respectively.     

Crop Growth, Disease and Yield Components of Rusted Phaseolus Beans in Ethiopia

Crop growth and disease epidemics in sprayed and non-sprayed bean plots, artificially infected with rust (Uromyces appendiculatus) 3 weeks after emergence. were assessed weekly in two cultivars, at two locations for two seasons. Disease intensity was regulated by the application of a fungicide at 5 spray frequencies. Fungicide application influenced leaf area index (LAI) and reduced rust intensity. The fungicide had no significant effect on other diseases and dead leaf area. Fungicide application increased seed yield (SY) by increased numbers of pods per plant (PP). Rust severity was strongly correlated with pustule density but the overall relationships among rust assessment parameters depended on cultivar and location. Seed yield and pods per plant were highly correlated with LAI. The relationships between LAI and seeds per pod or seed weight depended on cultivar and location. Overall rust assessment parameters (rust severity and pustule density) showed close, negative relationships with seed yield. seed weight and pods per plant but not with seeds per pod. The relationships obtained in the partially resistant line 6-R-395 were less definite than those in the susceptible line Mexican 142. The yield parameters seed yield and pods per plant, showed strong positive relationships.     

Interactive effect of cytokinin and potassium on sink-source relationships in Lupinus angustifolius

This study examined whether increased K supply in conjunction with BAPcould increase lupin seed yield and harvest index by enlarging sink volume (podnumber), increasing assimilate and improving assimilate partitioning to filltheadditional pods induced by BAP treatment. Narrow-leafed lupin(Lupinusangustifolius, cv. Danja abs^– mutant) was grown inaglasshouse, in pots containing sandy soil with four K treatments (0, 15, 60 and120 mg K/kg soil). BAP (2 mM) was applied daily toallmain stem flowers throughout the life of each flower from opening to senesced.BAP application did not affect assimilate production (as measured by totalabove-ground biomass), but changed assimilate partitioning. On BAP-treatedplants, there were greater proportions of seed to pod wall dry weight on themain stem but smaller proportions on the branches, and an increased weightratioof seed to pod wall overall which meant more assimilate was used for seedgrowthrather than pod wall growth. BAP increased the number of pods per plant by35% and this more than compensated for the decreases in seeds per podandseed weight. Therefore, there was an increased harvest index (+11%)and seed yield per plant (+13%) in BAP-treated plants. BAP alsoincreased the number of pods with filled seeds (146%) on the main stemand main stem seed K⁺ concentration (from 0.81% to0.87%). Added K increased biomass but only slightly affected assimilatepartitioning. As applied K increased, relatively more assimilate was used forpod wall growth rather than seed growth. Added K increased seed yield per plantby about 14% due to increases in seed weight and the number of pods onthe main stem. Moreover, K⁺ concentration in seeds and shootsincreased with increasing level of applied K. Seed yield was enhanced more byBAP when K was supplied at high levels. Increasing K supply interactedpositively with added BAP by increasing narrow-leaf lupin seed yield andharvestindex through increases in assimilate supply and its partitioning into seeds.     

两种互逆资源梯度影响下刺叶锦鸡儿的种子选择性败育格局

种子的选择性败育在被子植物中普遍存在,开展结籽格局及其影响因素的研究有助于深入了解种子的形成机制及多样化的生殖对策。以刺叶锦鸡儿Caragana acanthophylla为材料,通过传粉过程、胚珠发育动态和资源分配状况的研究,以探讨种子的选择性败育格局及相关影响因素。结果显示：(1)刺叶锦鸡儿具高度自交不亲和性,为泛化的传粉系统,蜂类是主要的传粉者。自然状态的结实率为(86.00±4.96)%,不存在传粉限制,但受精具明显的时间效应。(2)刺叶锦鸡儿单花期4—5d,每朵花有(14.00±0.14)粒胚珠。胚珠的发育从荚果顶部开始,其中,开花后第3天荚果顶部胚珠开始膨大;第11天绝大多数胚珠出现了膨大,此时,在荚果基部的胚珠开始败育,随后荚果顶端受精后的胚珠也出现败育,最终仅荚果中部形成2—3粒种子。其结籽格局为成熟荚果中部胚珠,而败育荚果顶部和基部胚珠的选择性败育类型。(3)受微地形影响,居群内开花植株具斑块分布,对较少开花植株通过添加水肥进行资源调控后,结籽率显著提高,说明在种子形成过程中存在资源限制。综上所述,受精顺序和资源限制两个互逆的资源梯度决定了刺叶锦鸡儿的结籽格局。其中,...     

大豆花荚败育期间的植物激素变化

大豆开花结荚期,不同发育阶段的幼蕾与花荚的脱落率不同,其中以花后５ｄ内的幼荚脱落最严重。与败育花荚相比,正常花荚中的干物质积累量均较高。细胞分裂素（ＤＨＺＲｓ,ＺＲｓ,ｉＰＡ）含量也较高,花后３～５ｄ的幼荚中表现更明显。脱落酸（ＡＢＡ）则是以败育幼蕾及花后３～５ｄ的幼荚中含量较高。不同发育阶段的大豆生殖器官中,正常开放花中的玉米赤霉烯酮（ＺＥＮ）含量最高