共查询到20条相似文献,搜索用时 15 毫秒
1.
Quantitative studies of the translocation of radiocarbon from a young expanded leaf of two tall varieties (Improved Pilot and Thomas Laxton) and two dwarf varieties (Little Marvel and Meteor) of Pisum sativum showed that 40 to 45 per cent of the radiocarbon was exported from the 14CO 2 treated leaf after 24 hours in all four varieties. Although substantial export to the upper shoot always occurred it was more marked in the two tall varieties. Pre-treatment with GA did not affect total fixation but increased total export from the 14CO 2 treated leaf in cv. Meteor and decreased it in cv. Improved Pilot. GA had no effect on the translocation pattern in the tall plants but modified that of the dwarf plants to correspond to that found in the tall varieties. 相似文献
2.
Rate of photosynthesis and activities of photosynthetic carbon reduction cycle enzymes were determined in pods (siliqua),
whereas rate of dark CO 2 fixation, oil content and activities of enzymes involved in dark CO 2 metabolism were measured in seeds of Brassica campestris L. cv. Toria at different stages of pod/seed development. The period between 14 and 35 days after anthesis corresponded to
active phase of seed development during which period, seed dry weight and oil content increased sharply. Rate of pod photosynthesis
and activities of photosynthetic carbon reduction cycle enzymes were maximum in younger pods but sufficiently high levels
were retained up to 40 days after anthesis. The rate of dark 14CO 2 fixation in seeds increased up to 21 days after anthesis and declined thereafter but maintaining sufficiently high rates
till 35 days after anthesis. Similarly various enzymes viz., phosphoenolpyruvate carboxylase, NAD +-malate dehydrogenase and NADP +-malic enzyme, involved in dark CO 2 metabolism retained sufficient activities during the above period. These enzyme activities were more than adequate to maintain
the desired supply of malate which mainly arises from dark CO 2 fixation in seeds and further translocated to leucoplasts for onward synthesis of fatty acids. Enzyme localization experiments
revealed phosphoenolpyruvate carboxylase and enzymes of sucrose metabolism to be present only in cytosol, whereas enzymes
of glycolysis were present both in cytosolic and leucoplastic fractions. These results indicated that oil synthesis in developing Brassica seeds is supported by pod photosynthesis and dark CO 2 fixation in seeds as the former serves as the source of sucrose and the latter as a source of malate 相似文献
3.
The effects of CO 2 concentration and illumination on net gas exchange and the pathway of 14CO 2 fixation in detached seeds from developing fruits of Lupinus albus (L.) have been studied. Increasing the CO2 concentration in the surrounding atmosphere (from 0.03 to 3.0% [v/v] in air) decreased CO2 efflux by detached seeds either exposed to the light flux equivalent to that transmitted by the pod wall (500 to 600 micro-Einsteins per square meter per second) in full sunlight or held in darkness. Above 1% CO2 detached seeds made a net gain of CO2 in the light (up to 0.4 milligrams of CO2 fixed per gram fresh weight per hour) but 14CO2 injected into the gas space of intact fruits (containing around 1.5% CO2 naturally) was fixed mainly by the pod and little by the seeds. Throughout development seeds contained ribulose-1,5-bisphosphate carboxylase activity (EC 4.1.1.39), especially in the embryo (up to 99 micromoles of CO2 fixed per gram fresh weight per hour) and phosphoenolpyruvate carboxylase (EC 4.1.1.31) in both testa (up to 280 micromoles of CO2 fixed per gram fresh weight per hour) and embryo (up to 355 micromoles of CO2 fixed per gram fresh weight per hour). In kinetic experiments the most significant early formed product of 14CO2 fixation in both light and dark was malate but in the light phosphoglyceric acid and sugar phosphates were also rapidly labeled. 14CO2 fixation in the light was linked to the synthesis of sugars and amino acids but in the dark labeled sugars were not formed. 相似文献
4.
The rate of photosynthesis ( P
N) in leaves and pods as well as carbon isotope content in leaves, pod walls, and seeds was measured in well-watered (WW) and water-stressed (WS) chickpea plants. The P
N, on an area basis, was negligible in pods compared to leaves and was reduced by water stress (by 26%) only in leaves. WS pod walls and seeds discriminated less against 13CO 2 than did the controls. This response was not observed for leaves as is usually the case. Pod walls and seeds discriminated less against 13CO 2 than did leaves in both WW and WS plants. Measurement of carbon isotope composition in pods may be a more sensitive tool for assessing the impact of water stress on long-term assimilation than is the instantaneous measurement of gas exchange rates. 相似文献
5.
By pulse-labeling field-grown soybean leaves for 60 seconds at midday with 14CO 2 and then sequentially harvesting, dissecting, and extracting the radioactive fruit tissues (of pod and seeds), the route, uptake kinetics, and metabolic fate of 14C-photosynthate as it was imported by 35- to 40-day-old pods were determined. As the [ 14C]sucrose pulse entered the pods, the seeds became radioactive immediately but a lag of nearly 30 minutes occurred before label could be detected in the pod wall pericarp. 相似文献
6.
In vivo net CO 2 exchange characteristics of attached Brassicapods were studied during the entire period of their growth anddevelopment after anthesis. 14CO 2 was fed both from the externalatmosphere and internally through the pod cavity, and the anatomyof the pod-wall was examined microscopically. Stomata were observedin the outer epidermal layer of the pod wall. Net in vivo CO 2fixation by the pods was observed throughout the period of theirdevelopment and was maximum on day 42 after anthesis (DAA).Compared to the internal feeding experiments, 14CO 2 fixationfrom the external environment was very high. Apparent translocationof fixed carbon from the pod wall to seeds was rapid. Pod photosynthesiscontributed substantially to seed growth. pods, Brassica campestris L., CO 2 fixation, stomata 相似文献
7.
In vivo net CO 2 exchange characteristics of attached Brassicapods were studied during the entire period of their growth anddevelopment after anthesis. 14CO 2 was fed both from the externalatmosphere and internally through the pod cavity, and the anatomyof the pod-wall was examined microscopically. Stomata were observedin the outer epidermal layer of the pod wall. Net in vivo CO 2fixation by the pods was observed throughout the period of theirdevelopment and was maximum on day 42 after anthesis (DAA).Compared to the internal feeding experiments, 14CO 2 fixationfrom the external environment was very high. Apparent translocationof fixed carbon from the pod wall to seeds was rapid. Pod photosynthesiscontributed substantially to seed growth. pods, Brassica campestris L, CO 2 fixation, stomata 相似文献
8.
A precursor in tetrapyrrole biosynthesis, 5-aminolevulinic acid (ALA), was applied via presowing soaking in Vigna catjung,
V. mungo, and V. radiata. ALA increased plant growth and influenced dry matter accumulation in leaves, stems, and pods through
increased chlorophyll content and photosynthetic CO 2 absorption. At harvest, ALA treated plants had increased number of pods per plant, seeds per pod, 100 seed dry matter, biological
yield, and the harvest index. Therefore, pretreatment of seeds with optimal concentration of ALA is recommended for improving
the growth and productivity of tropical legumes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
Field experiments were conducted in 1981 and 1982 to study the effects of low-irradiance supplemental light on soybean ( Glycine max [L.] Merr. cv Evans) flower and pod abscission. Cool-white and red fluorescent lights illuminated the lower part of the soybean canopy during daylight hours for 3 weeks late in flowering. At the same time, flowers and young pods on half the plants were shaded with aluminum foil. Flowers were tagged at anthesis and monitored through abscission or pod maturity. Responses to red and white lights were similar. Supplemental light tended to reduce abscission and increase seed weight per node compared to natural light. Shading flowers and pods increased abscission and reduced seed weight per node. Number of flowers produced per node, individual seed weight, and seeds per pod were not affected by light or shade treatments. Further studies examined the effects of shading reproductive structures on their capacity to accumulate 14C-photoassimilates. Individual leaves were pulse labeled with 14CO2 1, 2, and 4 weeks post anthesis. Flowers and pods in the axil of the labeled leaf were covered with aluminum foil 0, 24, 72, and 120 hours before pulsing. Shading flowers and pods resulted in a 30% reduction in the relative amount of radiolabel accumulated from the source leaf. The reduction in 14C accumulation due to shading was evident regardless of the length of the shading period and was most pronounced when the shades were applied early in reproductive development. We conclude that light perceived by soybean flowers and young pods has a role in regulating both their abscission and their capacity to accumulate photoassimilates. 相似文献
10.
The mineral nutrition of fruiting plants of Pisum sativum L.,Lupinus albus L. and Lupinus angustifolius L. is examined insand cultures supplying adequate and balanced amounts of essentialnutrients. Changes in content of specific minerals in leaves,pods, seed coat, and embryo are described. P, N and Zn tendto increase precociously in an organ relative to dry matteraccumulation, other elements more or less parallel with (K,Mn, Cu, Mg and Fe) or significantly behind (Ca and Na) dry weightincrease. Some 6090 per cent of the N, P and K is lostfrom the leaf, pod and seed coat during senescence, versus 2060per cent of the Mg, Zn, Mn, Fe and Cu and less than 20 per centof the Na and Ca. Mobilization returns from pods are estimatedto provide 439 per cent of the seeds' accumulations ofspecific minerals, compared with 427 per cent for testatransfer to the embryo. Endosperm minerals are of only minorsignificance in embryo nutrition. Comparisons of the mineral balance of plant parts of Lupinusspp. with that of stem xylem sap and fruit tip phloem sap supportthe view that leaves and pod are principal recipients of xylem-borneminerals and that export from these organs via phloem is themajor source of minerals to the seeds. Endosperm and embryodiffer substantially in mineral compostition from phloem sap,suggesting that selective uptake occurs from the translocationstream during seed development. Considerable differences are observed between species in mineralcomposition of plant organs and in the effectiveness of transferof specific minerals to the seeds Differences between speciesrelate principally to Ca, Na and certain trace elements. 相似文献
11.
The heritability, the number of segregating genes and the type of gene interaction of nine agronomic traits were analysed
based on F 2 populations of synthetic oilseed Brassica napus produced from interspecific hybridization of B. campestris and B. 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 was y = 0.074x 8 + 1.819x 9 + 6.72x 12 -60.78 ( R
2 = 0.993), where x
8, x 9 and x 12 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 F 2 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 F 2 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. 相似文献
12.
Summary The total amount of nitrogen derived from symbiotic nitrogen fixation in two pea and one field bean cultivar, supplied with
50 kg N ha −1 at sowing (‘starter’-N), was estimated to 165, 136, and 186 kg N ha −1, respectively (three-year means). However, estimates varied considerably between the three years. At the full bloom/flat
pod growth stage from 30 to 59 per cent of total N 2 fixation had taken place. The proportion of total N derived from N 2 fixation at maturity was higher in seeds than in vegetative plant parts and amounted to 59.5, 51.3 and 66.3 per cent of total
above-ground plant N in the two pea cultivars and field bean, respectively (three-year means). The recovery of fertilizer
N was 62.2, 70.2, 52.1, and 69.5 per cent in the two pea cultivars, field bean and barley, respectively. Growth analysis indicated
that barley did not meet the claims for an ideal reference crop in the 15N fertilizer dilution technique for estimating N 2 fixation in pea and field bean. ‘Starter’-N neither increased the seed yield nor the N content of the grain legumes. 相似文献
13.
Summary The photosynthetic capacity and carbon metabolism of the fruits of Isomeris arborea (Capparidaceae), an evergreen shrub endemic to the desert and coastal habitats of Southern California and Baja California, are described. The inflated structure of the pods of I. arborea provides a model system for experimental studies of fruit photosynthesis in native plants since the gas concentration of the internal space can be manipulated and monitored separately from the external pod environment. CO 2 released by seed respiration is partially contained in the inner gas space of the pods, resulting in an elevated CO 2 environment inside the fruit (500 to 4000 mol mol –1 depending on the stage of fruit development). A portion of this CO 2 is assimilated by the inner layers of the pericarp, but a larger fraction leaks out. The photosynthetic layers of the pericarp use two different sources of CO 2: the exocarp fixes exogenous CO 2 while the endocarp fixes CO 2 released by seed respiration into the pod cavity. Even though the total weight of the fruit increases during development, the combined rates of fixation of externally and internally supplied CO 2 remained constant (10–11 mol CO 2 pod –1 h –1). After the pods attain maximum volume, the major change in gas exchange that takes place during fruit growth is a gradual increase in the amount of respiratory CO 2 released by the seeds. This shifts the CO 2 balance of the fruit from positive, in young fruits, to negative in mature fruits. Pericarp photosynthesis helped support not only the cost of fruit maintenance, but also the cost of fruit growth, particularly during the first stages of fruit development. During later fruiting stages insufficient carbon is fixed to fully supply either respiration or growth. 相似文献
14.
The experimental study was conducted during the period of 2008–2010 at the experimental field of the Institute of Forage Crops
in Pleven. The hybridization scheme included direct and back crosses covering four varieties of forage pea ( Pisum sativum L.), namely two spring ones, Usatii 90 and Kamerton from Ukraine, and a winter one from Bulgaria, Pleven 10. There was analyzed
the inheritance of quantitative traits such as plant height, height to first pod, pod number per plant, seed number per plant,
seed number per pod, seed weight per plant and number of fertile nodes per plant of parental components (P 1 and P 2) and both first (F 1) and second (F 2) hybrid generations. The cross Usatii 90 × Pleven 10 showed the highest real heterosis effect for plant height (8.26%), pods
per plant (158.79%), seeds per plant (272.16%), seeds per pod (42.09%), seed weight per plant (432.43%) and number of fertile
nodes per plant (117.14%). The cross Pleven 10 × Usatii 90 had the highest real heterosis effect height to first pod (11.06%).
In F 2 plants, the strongest depression for plant height (5.88%), seeds per plant (57.88%), seeds per pod (55.93%) and seed weight
per plant (55.99%) was in the cross Usatii 90 × Pleven 10, for height to first pod (1.47%) in the cross Kamerton × Pleven
10 and for number of fertile nodes per plant (15.91%) in the cross Pleven 10 × Usatii 90. The highest positive degree of transgression
for number of fertile nodes per plant (165.64%) and seed weight per plant (162.10%) was in the cross Pleven 10 × Kamerton
and for pod number per plant (102.54%) and seeds per plant (99.13%) in Kamerton × Pleven 10. The stability of the characters
was determined. Low variability in F 1 and F 2 was found in plant height (3.97–6.85%). Variability of number seeds per plant in F 1 was highest (11.86–33.23%). For all other traits, the variability varied from average to high. A lower narrow-sense heritability
coefficient was observed for plant height, height to first pod, pods per plant, seeds per plant and seed weight per plant
(from 0.001 to 0.230). In few cases, such as in fertile nodes per plant (0.39 and 0.81) and seeds per pod (0.44), the coefficients
of broad-sense heritability were higher. 相似文献
15.
Summary ‘Pod washings’ were collected from groundnut at three hour intervals for 24 hours after feeding the plants with 14CO 2. Low radioactivity was found in the first four ‘Pod washings’ of 10 day old pods and the radioactivity increased with time.
Highest radioactivity was found in washings of 20 and 30 day old pods and was twice the activity found in the washings of
50 day old pods. The radioactivity of both ethanol-soluble and insoluble fractions in pods was determined. The radioactivity
mobilized into the pods increased with age and it was highest in 50 day old pods. The influence of the pod exudates on geocarposphere
microflora during pod development is discussed. 相似文献
16.
Field experiments were undertaken to study the pattern of distribution of photosynthate produced by the leaves and the pods of Phaseolus vulgaris (cv. Purley King) by means of the 14C technique. It was found that the UC photosynthate produced by a trifoliate leaf (38 days after anthesis) was shared almost equally between the leaf and the pod at its axil with 33–50% of the fixed 14C finding its way to the seeds in that pod. However, during the early stages of pod development (10 days after anthesis) some 13–14% of the fixed 14C was detected in the stem, indicating the inadequacy of the pod as a sink at that stage. When the pod was treated, virtually no 14C was detected in other parts of the plant. Of the 14C fixed by pod photosynthesis in the later stages (38 days after anthesis), 55–60% was translocated to the seeds within the same pod. These results indicate the importance of current photosynthesis during the pod fill stage in P. vulgaris as has been suggested in other grain legume crops. 相似文献
17.
The economy of functioning of the developing fruit of white lupin ( Lupinus albus L.) is assessed quantitatively in relation to intake and usage of carbon, nitrogen, and water. Of every 100 units of carbon imported from the parent plant, 52 are incorporated into seeds, 37 into nonmobilizable material of the pod, and the remaining 11 lost as CO 2 to the atmosphere. An illuminated fruit can make net gains of CO 2 from the atmosphere during the photoperiods of all but the last 2 weeks of its life, suggesting that it is active in assimilation of CO 2 respired from pods and seeds. This conservation activity is important to carbon economy. 相似文献
18.
The effect of genes ar (violet flowers, small hilum) and n (thick,fleshy pod wall) on whole plant in senescence peas was examinedby comparing Ar- with arar and N- with nn plants in segregatingprogenies. Homozygosity for ar or n significantly delayed the time whenthe plants were ready for harvest of their entire seed crop.These genes did not delay either the onset of reproduction orthe onset of apical arrest in the first instance. However, whereas Ar- N- plants almost invariably senesced and died as the firstseed crop matured, the majority of arar and/or nn plants entereda period of secondary growth and a further fruiting cycle. Comparedwith Ar- plants, arar plants had over twice as many pods andseeds but individual seeds were 58 per cent lighter and totalseed yield (wt) was 19 per cent less. Pod length was unaffected.Compared with N-plants, nn plants had shorter pods (16 per cent),fewer seeds per pod (21 per cent), smaller seeds (20 per cent)and a lower total seed yield (wt 14 per cent less). It appearsthat ar and n impose a lower metabolic drain per reproductivenode as a consequence of their effects on hilum anatomy andpod morphology, respectively. These mutants disrupt the normalpattern of monocarpic senescence by breaking the coordinationbetween apical arrest and subsequent events. The developingseed crop delimited by the first arrest fails to cause plantdeath, possibly because sink size is less than in normal counterparts. Pisum sativum L, garden pea, senescence, hilum, pod, seed size, genetics 相似文献
19.
The auxin 4-chlorophenoxyacetic acid (4-CPA) has been found to delay the maturation and dehiscence of the pods of oil seed rape. Dipping pods in solutions of 500 gl –1, 4-CPA, 36 and 39 days after anthesis delayed significantly the autolysis of the thin-walled parenchyma of the dehiscence zones, the senescence of the pod walls and the loss of water from the pod walls and seeds. Increases in both the fresh and dry weights of both pod walls and seeds were recorded in the treated pods as compared with controls. 相似文献
20.
The distribution of labelled assimilates following the assimilation of 14CO 2 in groundnut ( Arachis hypogaea L.) by single leaves at different nodes was investigated using autoradiographic technique. In the vegetative stage growing leaves assimilated most of the 14carbon, while the fully expanded leaves exported most of its radiocarbon to the apices, young expanding leaves and to the roots. Soon after the formation of the pegs and the growth and development of the pods, the developing pods become the major sinks. At this stage translocation from the foliage of each branch was restricted mostly to the pods produced by this branch. 相似文献
|