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1.
Jack Van't Hof 《American journal of botany》1999,86(6):776-779
The nuclear DNA content of developing cotton fiber cells (Gossypium hirsutum, cv. MD51ne) increases ∼24% after 2 d postanthesis (dpa). The amount of nuclear DNA at 2 dpa is 5.4 ± 0.27 pg. At 3–4 dpa it increases to 6.7 ± 0.24 pg and by 5 dpa it is 6.8 ± 0.70 pg. These values were obtained by nuclear fluorescence after staining with Hoechst 33258. Human oral squamous cell nuclei were used as a DNA standard. Nuclear DNA content increases in fibers growing on either fertilized or unfertilized ovules. The increase also is detectable in Feulgen stained nuclei using two-wavelength cytospectrophotometry. All measurements were made on isolated fiber cell nuclei using a newly developed method tailored to cotton fiber cells. The results imply that during the early stages of development fiber cell nuclei either selectively amplify certain sequences or enter S-phase replicating a portion of their genome. 相似文献
2.
To determine whether unfertilized ovules continue to grow when in an ovary containing fertilized ovules, we measured ovule lengths in developing fruits of Epilobium obcordatum that were harvested 4, 5, 8, and 10 d post pollination. We found that unfertilized ovules that were in the presence of fertilized ovules continued to grow and that there was a broad range of overlap in their sizes at all sampling times. This effect was found for two types of unfertilized ovules that occur throughout the length of the ovary: normal, unfertilized ovules, apparently bypassed by pollen tubes; and sterile ovules lacking an embryo sac. In addition, there is a position effect within developing fruits. Both fertilized and unfertilized ovules are larger at the stylar end. In six samples resulting from pollination with a single pollen tetrad, a total of 18 embryos were found, and the effect on unfertilized ovules, greatest at the stylar end, diminished with distance from the ovules with embryos. Our results are consistent with the interpretation that diffusible hormones produced by developing seeds cause nearby unfertilized ovules to grow. We conclude that caution is necessary when attempting to infer ovule fertilization histories from the appearances of ovules in developing and mature fruits. What are often inferred to be aborted seeds, in many cases, may not be seeds at all. They may be enlarged, unfertilized ovules. 相似文献
3.
Potassium antimonate was used to localize Ca2+ in tobacco ovules from 0 to 7 d after anthesis in pollinated and emasculated flowers. Antimonate binds “loosely bound” Ca2+ into calcium antimonate; less-soluble forms are unavailable and free calcium usually escapes. Ovules are immature at anthesis.
Abundant calcium precipitates in nucellar cells surrounding the micropylar canal. A difference between calcium in the two
synergids emerges at 1 d, which is enhanced in pollinated flowers. The future receptive synergid accumulates more precipitates
in the nucleus, cytoplasm and cell walls. After fertilization, micropyle precipitates diminish, and the ovule is unreceptive
to further tube entry. In emasculated flowers 6 d after anthesis, ovular precipitates essentially disappear; however, flowers
pollinated at 4–5 d and collected 2 d later largely restore their prior concentration of precipitates. Ovular precipitates
occur initially in the nucellus, then the embryo sac, and finally the synergid and micropylar filiform apparatus. Possibility,
calcium is released from the embryo sac, although no structural evidence of exudate formation was observed. Calcium precipitates
in the ovule correlate with the ability of the ovule to be fertilized, suggesting that successful pollen tube entry and later
development may require calcium of the class precipitated by antimonate.
Received: 14 August 1996 / Accepted: 9 October 1996 相似文献
4.
Torenia fournieri Lind. has a naked embryo sac that protrudes from the micropyle. The precise time course of the entire process of double fertilization
and the kinetics of fertilization events were determined in this species by the following methods: (i) without squashing,
pollen tubes on the torn stylar canal were observed by fluorescence microscopy after staining with both 4′,6-diamidino-2-phenylindole
(DAPI) and aniline blue; and (ii) large numbers of living embryo sacs were observed directly by differential interference
microscopy before and after fertilization. The pollen began to germinate 5 min after pollination and extruded pollen tubes
which elongated at a constant rate of 2.3 mm · h−1. At 4.0 h after pollination, the mitotic index of the generative cell within the pollen tube reached 88% and the two sperm
cells were formed. Pollen tubes began to arrive at ovules 8.9 h after pollination and directly entered one of two synergids
in the naked embryo sac. The time required for transport of sperm cells in the degenerated synergid was estimated statistically
to be 1.9 ± 1.8 min for transport of the first cell and 7.4 ± 1.6 min for the second. In the nucleus of the fertilized egg
cell, the male nucleolus began to emerge 10 h after pollination and the female nucleolus often decreased in size. The two
nucleoli fused together prior to elongation of the zygote, which began 28 h after pollination. In the central cell, the secondary
nucleus migrated to a region adjacent to the egg apparatus after pollination but prior to the arrival of the pollen tube.
The primary endosperm nucleus rapidly returned to the inner region after fertilization. Prior to embryogenesis, the first
division of the primary endosperm began about 15 h after pollination, at a defined site, to form the chalazal haustorium.
Received: 24 October 1996 / Accepted: 13 March 1997 相似文献
5.
The peanut (Arachis hypogaea L.) produces flowers aerially, but buries the recently fertilized ovules into the soil, where fruit and seed development
occur. The young seeds are carried down into the soil at the tip of a specialized organ called the gynophore. Although the
gynophore has a typical shoot anatomy, it responds positively to gravity like a root. In this study, we explore the role of
the plant growth regulator indole-3-acetic acid (IAA) in the growth and the gravitropic response of the peanut gynophore.
With an immunolocalization technique using an IAA monoclonal antibody, we localized IAA within the tissues of vertically oriented
and gravistimulated gynophores. We found that in vertically oriented gynophores, IAA labeling occurs in the periphery of the
gynophore, in the entire cortex and epidermis. Within 20 min of horizontal reorientation, the IAA signal gradually increases
in the upper cortex/epidermis and diminishes in the lower cortex/epidermis. At 1.5 h after gravistimulation, all of the IAA
immunolocalization signal is detected in the upper cortex and epidermis – none is detected in the lower side. Growth rate
measurements also indicate that after 1–2 h of reorientation, the growth rate maximum on the upper side corresponds temporally
and spatially to the growth rate minimum on the lower side. Experiments using radioactively labeled IAA corroborate an upper-side
redistribution of this hormone upon horizontal reorientation. These results are analyzed with respect to the current theories
of plant gravitropic response, and a model for a possible gravity-induced IAA redistribution from the lower to the upper side
of the peanut gynophore is proposed.
Received: 25 January 1999 / Accepted: 24 February 1999 相似文献
6.
Effect of plant growth regulators on in vitro fiber development from unfertilized and fertilized Egyptian cotton ovules 总被引:2,自引:0,他引:2
Osama A. Momtaz 《Plant Growth Regulation》1998,25(3):159-164
Unfertilized and fertilized ovules of Gossypium barbadense Giza 45 (extra long staple variety) were used to study the effect of plant growth substances (auxins, gibberellins and cytokinins) on in vitro fiber initiation and development. Kinetin, alone did not increase total fiber unit (TFU) of unfertilized ovules, while an increase in TFU value occurred when a constant level of IAA and GA3 were used either separately or in combination in the liquid medium. GA3 used alone, produced a higher TFU value than that produced by IAA, whilst, IAA with a constant level of GA3 (5 M) produced the highest value of TFU. GA3 with a constant level of IAA (5 M) produced a lower TFU value. Kinetin reduced the stimulatory effect of IAA and GA3 on TFU value when used in combination with either substance. In fertilized ovules, the highest level of TFU was reached when IAA, with a constant level of GA3, was added to the medium, whilst its lowest level was obtained when IAA was used alone. Estimation of in vitro fiber production, as well as the effect of growth substances used in different concentrations on in vitro fiber initiation and development from unfertilized and fertilized ovules of Egyptian cotton varieties Gossypium barbadense Giza 45 are discussed. 相似文献
7.
Autonomous endosperm was found in unfertilized ovules of V. odorata L. cultured on MS medium supplemented with 2,4-D as a sole growth regulator or on media with 2,4-D and BAP or kinetin. Frequency
of endosperm induction was approximately 9% in ovules analyzed. The induction rate depended mainly on genotype of the donor
plant, and to lesser degrees, on floral stage, flower series and medium type. Multinuclear endosperms consisting of 10–37
nuclei were found in ovules after as few as 4 days of culture. In some ovules at this stage, the egg cell and two polar nuclei
were present. The process of endosperm degeneration began after 3 weeks of culture. In some ovules, degenerating autonomous
endosperm was observed up to the 7th week. Parthenogenetic development of egg cells or apogamy did not accompany autonomous
endosperm, supporting the hypothesis of independent pathways for embryo and endosperm development.
Received: 1 December 1998 / Revision accepted: 6 April 1999 相似文献
8.
An ultrastructural study of early endosperm development and synergid changes in unfertilized cotton ovules 总被引:4,自引:0,他引:4
Excised, unfertilized cotton (Gossypium hirsutum L.) ovules were cultured for 1–5 days postanthesis and embryo-sac development was studied with the electron microscope. In some ovules the two polar nuclei fuse and the diploid endosperm nucleus goes through a limited number of free nuclear divisions after 2–3 days in culture. Each nucleus has two nucleoli, in contrast to nuclei of fertilized triploid endosperm which have three nucleoli. Precocious cell walls form between the endosperm nuclei on the 3rd day in culture. The morphology of the plastids, mitochondria, rough endoplasmic reticulum (RER), dictyosomes and microbodies, and the amount of starch and lipid in the diploid cellular endosperm are similar to those of the central cell. A few large helical polysomes appear close to plastids and mitochondria. After 2 days in culture, one of the two synergids in the unfertilized cultured ovules shows degenerative changes which in fertilized ovules are associated with the presence of the pollen tube, i.e., increase in electron density, collapse of vacuoles, irregular darkening and thickening of mitochondrial and plastid membranes, disappearance of the plasmalemma and the membranes of the plasmalemma and the membranes of the RER. The second synergid remains unchanged in appearance. The egg cell does not shrink or divide or show structural changes characteristic of the cotton zygote. Embryo-sac development is arrested on the 4th and 5th days in culture. The nucellus continues growth and at 14 days crushes the degenerate embryo sac. 相似文献
9.
Microspores of Brassica napus L. cv. Topas, undergo embryogenesis when cultured at 32.5 °C for the first 18–24 h and then at 25 °C. The first division
in heat-treated microspores is a symmetric division in contrast to the asymmetric division found after the first pollen mitosis
in-planta or in microspores cultured continuously at 25 °C. This asymmetric division is unique in higher plants as it results
in daughter cells separated by a non-consolidated wall. The cytoskeleton has an important role in such morphological changes.
We examined microtubule (MT) organization during the first 24 h of heat induction in the embryogenic B. napus cv. Topas and the non-embryogenic B. napus breeding line 0025. Preprophase bands (PPBs) of MTs appeared in cv. Topas microspores in late uninucleate microspores and
in prophase figures after 4–8 h of heat treatment. However, more than 60% of the PPBs were not continuous bands. In contrast,
PPBs were never observed in pollen mitosis; MT strands radiated from the surface of the nuclear envelope throughout microspore
maturation to the end of prophase of pollen mitosis I, during in-planta development and in microspores cultured at 25 °C.
Following 24 h of heat treatment, over 95% of the microspores appeared to have divided symmetrically as indicated by the similar
size of the daughter nuclei, but only 7–16% of the microspores eventually formed embryos. Discontinuous walls were observed
in more than 50% of the divisions and it is probable that the discontinuous PPBs gave rise to such wall abnormalities which
may then obstruct embryo development. Preprophase bands were not formed in heat-treated microspores of the non-embryogenic
line 0025 and the ensuing divisions showed discontinuous walls. It is concluded that the appearance of PPBs in heat-induced
microspores marks sporophytic development and that continuous PPBs are required for cell wall consolidation and embryogenesis.
It follows that induced structures with two equally condensed nuclei, do not necessarily denote symmetric divisions.
Received: 22 October 1998 / Accepted: 28 November 1998 相似文献
10.
11.
Polysaccharide and glycoprotein distribution in the epidermis of cotton ovules during early fiber initiation and growth 总被引:1,自引:0,他引:1
The cotton fiber is a model system to study cell wall biosynthesis because the fiber cell elongates (∼3 cm in ∼20 days) without
mitosis. In this study, developing cotton ovules, examined from 1 day before anthesis (DBA) to 2 days post-anthesis (DPA),
that would be difficult to investigate via classical carbohydrate biochemistry were probed using a battery of antibodies that
recognize a large number of different wall components. In addition, ovules from these same stages were investigated in three
fiberless lines. Most antibodies reacted with at least some component of the ovule, and several of the antibodies reacted
specifically with the epidermal layer of cells that may give clues as to the nature of the development of the fibers and the
neighboring, nonfiber atrichoblasts. Arabinogalactan proteins (AGPs) labeled the epidermal layers more strongly than other
ovular tissue, even at 1 DBA. One of the AGP antibodies, CCRC-M7, which recognizes a 1➔6 galactan epitope of AGPs, is lost
from the fiber cells by 2 DPA, although labeling in the atrichoblasts remained strong. In contrast, LM5 that recognizes a
1➔4 galactan RGI side chain is unreactive with sections until the fibers are produced and only the fibers are reactive. Dramatic
changes also occur in the homogalacturonans (HGs). JIM5, which recognizes highly de-esterified HGs, only weakly labels epidermal
cells of 1 DBA and 0 DPA ovules, but labeling increases in fibers cells, where a pectinaceous sheath is produced around the
fiber cell and stronger reaction in the internal and external walls of the atrichoblast. In contrast, JIM7-reactive, highly
esterifed HGs are present at high levels in the epidermal cells throughout development. Fiberless lines displayed similar
patterns of labeling to the fibered lines, except that all of the cells had the labeling pattern of atrichoblasts. That is,
CCRC-M7 labeled all cells of the fiberless lines, and LM5 labeled no cells at 2 DPA. These data indicate that a number of
polysaccharides are unique in quantity or presence in the epidermal cell layers, and some of these might be critical participants
in the early stages of initiation and elongation of cotton fibers. 相似文献
12.
The influence of 23 years of phosphorus (P) application at three annual rates of 0, 17.5 and 52.5 kg ha–1 on arbuscular mycorrhizal (AM) fungal colonization was studied 10 years after the fertilization treatment ended. The annual
application of 52.5 kg ha–1 was about twice the annual crop P extraction and after 23 years had resulted in a measured increase of 23% in the soil total-P
concentration. After 10 and 11 years without fertilization, the total mycorrhizal and arbuscular colonization of the plots
previously fertilized at this high rate were still significantly lower than in the plots subjected to the 0 and 17.5 kg ha–1 rates. Plots previously fertilized annually at the rate of 52.5 kg ha–1 also had a lower benefit : cost ratio for the symbiosis between AM fungi and plants. Furthermore, P-use efficiency was lower
in these plots, although no decrease in total dry matter production was found.
Accepted: 13 October 2000 相似文献
13.
Digital image analysis of expansion growth of cultured cotton ovules with fibers and their responses to ABA 总被引:1,自引:0,他引:1
Ling Fan Meng Lü Zhi-Yong Ni Wen-Ran Hu Juan Wang 《In vitro cellular & developmental biology. Plant》2011,47(3):369-374
Cotton ovule cultures have obvious advantages over whole plants when experimental protocols call for inhibitors, radio-labeled
precursors or controlled environmental conditions to be tested. The responses of ovule expansion growth and attached fiber
elongation to external factors require accurate measurement techniques. This paper presents a new method for digital image
analysis of the growth area of cotton ovules with fibers at high resolution. The method was characterized under constant conditions
and during dynamic responses to different levels of ABA (abscisic acid) treatment. The growth area was treated as area occupied
within the outline of the Petri dish image of the growing ovule with fibers. Growth area increase showed the same trends as
fiber length increase and was significantly correlated with the fiber length increase under different levels of ABA treatment
(r
2 = 0.97). This new analysis method provides a simple, noninvasive, and more accurate approach for growth analysis in the cotton
ovule culture system. Using this method, the effects of ABA on expansion growth of ovule with fibers were characterized. 相似文献
14.
Replicon spacing was measured during the S-phase of the cell cycle in shoot meristems of Silene coeli-rosa L., a long-day (LD) plant, and Pharbitis nil Chois, a short-day (SD) plant to examine the hypothesis that activation of latent origins of DNA replication is a feature
of floral determination. Silene coeli-rosa was germinated and grown in SD for 28 d and then exposed to either a florally inductive combination of 7 LD + 2 SD, the last
day of which coincides with determination of the sepal and stamen whorls, or was germinated and grown in 37 non-inductive
SD. Pharbitis nil was germinated and grown in continuous light (CL) for 5 d and then given either 48 h of inductive darkness followed by 1 d
of CL, the last day of which coincides with determination of the sepal, petal and stamen whorls, or given one of two independent
non-inductive treatments: 48 h dark interrupted by red light (R) + 1 d of CL, or 8 d of CL. Following these treatments, each
batch of plants was exposed to tritiated [methyl-3H]thymidine for 30, 60, 90 or 120 min. Apical domes were dissected, nuclei lysed and prepared as fibre autoradiographs from
which replicon size was recorded. In S. coeli-rosa, replicon size was in the range 10–15 μm in SD (non-inductive) and 0–5 μm in LD (inductive) while in P. nil it was 10–15 μm in the 48 h dark interrupted by R, 5–10 μm in CL (both non-inductive) but was reduced to 0–5 μm in the 48 h
dark treatment (inductive). Therefore, the recruitment of additional initiation points for DNA replication occurred in both
a LD and a SD plant immediately before the appearance of floral organs. The data are consistent in showing that a shortening
of S-phase, which is a characteristic feature of florally determined shoot meristems for both species, is brought about by
the activation of latent origins of DNA replication.
Received: 14 May 1998 / Accepted: 20 August 1998 相似文献
15.
The architecture of the nuclei of higher plants includes a structure similar to the nuclear lamina of vertebrates. Changes
in this structure were monitored during mitosis in carrot (Daucus carota L.) and celery (Apium graveolens L.) cells by immunofluorescence microscopy using an antibody that recognized the nuclear-matrix protein NMCP1. This protein
has been shown to be localized exclusively at the periphery of the nucleus (K. Masuda et al. 1997, Exp Cell Res 232: 173–187).
Immunofluorescence was recognized throughout cells in mitotic metaphase, although it was distributed predominantly in the
mitotic spindle zone. At late anaphase or telophase, the immunofluorescence was localized around each set of daughter chromosomes.
Immunofluorescence in newly formed daughter nuclei was restricted to the periphery of nuclei. This behavior was very similar
to that of the nuclear lamina of vertebrates, suggesting that the structure located between the nuclear envelope and the chromosomes
in plants disassembles and assembles in parallel with the disintegration and re-formation of the nuclear envelope.
Received: 30 April 1999 / Accepted: 26 June 1999 相似文献
16.
17.
The growth responses of lentil (Lens esculenta L. cv. Laird) and two wheat cultivars (Triticum aestivum L. cv. Laura and Neepawa) to Glomus clarum NT4 in soil containing indigenous arbuscular mycorrhizal fungi (AMF) and fertilized with phosphorus at different (0, 5, 10,
20 ppm) levels was studied in a growth chamber. Soil was inoculated with a monospecific culture of G. clarum NT4 to provide an inoculant:indigenous AMF ratio of ca. 1 : 100. The shoot and root growth, and AMF colonization levels of
NT4-inoculated lentil were significantly (P≤0.05) greater than the appropriate control plants in the unfertilized soil at 48 days after planting (DAP). At 95 DAP, NT4
inoculation had significantly increased the shoot dry weight (P≤0.08) and AMF colonization (P≤0.05) of lentil plants receiving 5 mg P kg–1 soil, whereas 20 mg P kg–1 soil reduced the shoot growth of NT4-inoculated plants. The NT4 inoculant had no effect (P≤0.05) on shoot P content, but increased (P≤0.08) the P-use efficiency of lentil plants receiving 5 mg P kg–1 soil. In contrast to the inoculant's effect on lentil, NT4 generally had no positive effect on any of the parameters assessed
for wheat cv. Laura at any P level at 48 or 95 DAP. Similarly, there was no positive effect of NT4 on shoot or root growth,
or AMF colonization of wheat cv. Neepawa plants at any P level at 48 DAP. However, NT4 inoculation increased the grain yield
of Neepawa by 20% (P≤0.05) when fertilized with 20 mg P kg–1 soil. This yield increase was associated with a significant (P≤0.05) reduction in root biomass and a significant (P≤0.05) increase in the grain P content of inoculated plants. Thus, NT4 appears to have a preference for the Neepawa cultivar.
Our results show that lentil was more dependent on mycorrhizae than wheat and responded to an AMF inoculant even in soil containing
high levels of indigenous AMF. It might, therefore, be possible to develop mixed inoculants containing rhizobia and AMF for
field production of legumes.
Accepted: 22 February 1997 相似文献
18.
Summary
Phaseolus coccineus typically has six linearly arranged ovules per ovary. The three ovules near the stylar end of the fruit (positions one, two, and three) are more likely to produce mature seeds, to produce heavier seeds, and to produce more vigorous progeny than the ovules in positions near the peduncular/basal end of the fruit (ovule positions four, five, and six). We conducted a series of field experiments designed to supplement our understanding of the mechanisms determining these position effects. We found that approximately 98% of the ovules in 752 fruits were fertilized — about 0.6% of the stylar ovules were not fertilized, whereas 3.2% of the basal ovules were unfertilized. Moreover, we found that only about 49% of the ovules in these 752 fruits produced mature seeds. Over 60% of the stylar ovules produced mature seeds, whereas only 37% of the basal ovules produced mature seeds. Consequently, the proportion of fertilized ovules cannot explain the differences in seed maturation among the ovule positions. We found that after 6.5 h most of the fertilized ovules were located in the stylar ovule positions, and that there were no fertilized ovules in ovule positions five and six, indicating that the stylar ovules are fertilized first. When only the fastest growing pollen tubes were permitted to enter the ovary (due to exision of the style), only the ovules at the stylar end were fertilized, indicating that the ovule positions that are fertilized first are indeed fertilized by the fastest growing pollen tubes.On leave from the Escuela de Biologia, Universidad de Costa Rica, Cuidad Universitaria Rodrigo Facio, San Jose, Costa Rica, Central America 相似文献
19.
H. R. Spieth 《Population Ecology》2002,44(3):0273-0280
The large white butterfly, Pieris brassicae, has an unusually complex life-history in its southernmost range in Western Europe. This complexity results (1) from two
developmental rests, a short-day induced hibernation and a long-day induced estivation response, and (2) from the exceptionally
early appearance of the first adult generation in January/February and a subsequent winter diapause in some of their progeny.
It was found that in spring and autumn, different generations are faced with critical photophases which induce hibernation
or estivation, with the consequence that in five out of six generations per year, only some develop directly whereas the others
enter a dormancy phase. To assess the implications of this high number of optional responses on the generation succession,
the development time was studied at various photoperiods and temperatures. The results showed that a threshold response determines
the duration of estivation. With unchanged summer conditions (daylengths ≥15 h) estivation lasts on average 18–19 weeks, while
with autumn conditions (daylengths ≤14 h) it lasts only 7 weeks. A change of photophases from ≥15 h to ≤14 h terminates estivation
within about 3–5 weeks, slightly depending on the pupal exposure time in summer conditions. The duration of estivation is
not affected by temperature or by the photophases experienced by the caterpillars. The winter diapause lasts 18–19 weeks on
average with winter conditions (12°C/10.30 h light), but only 8–10 weeks with late spring conditions (21°C/15 h light). These
results were used to assess the effects on the population phenology, with the finding that despite the different developmental
pathways, a desynchronization of the generation succession is largely prevented. Estivation, hibernation, and direct development
at different seasons are well adjusted to a common phenological pattern of a continuously reproducing population. This pattern
of activity covers a cryptic dormant subpopulation, and could not have been deduced by field observations.
Received: October 3, 2001 / Accepted: October 3, 2002 相似文献
20.
Two responses to elicitins are described in cultivars of radish (Raphanus sativus L.). Type I, exhibited by the cultivar Daikon, is characterised by wilting and desiccation within 24 h of elicitin application
and was previously reported as the sensitive response (S. Kamoun et al. 1993, Mol Plant-Microbe Interact 6: 15–25). At 1 μg
elicitin · g−1 FW radish tissue, symptoms appeared after 8 h, a sensitivity comparable to that shown by tobacco to β elicitins (J.-C. Pernollet
et al., 1993, Physiol Mol Plant Pathol 42: 53–67; S. Kamoun et al., 1993, Mol Plant-Microbe Interact 6: 15–25). Elicitin failed
to induce these symptoms in the cultivar White Icicle, even at 100 μg · g−1 FW of tissue. However, a different response (Type II) with symptoms resembling senescence appeared in White Icicle after
48 h and were fully developed by 72 h. The Type II response was induced at levels of elicitin above 0.3 μg · g−1 FW. Elicitin-treated Daikon leaves held at 100% relative humidity, rather than ambient (50–60%) did not wilt and by 72 h
displayed Type II symptoms. When treated Daikon leaves were removed to ambient humidity at any time during the latent period,
they developed Type I symptoms within 2 h. Although Type I symptoms were suppressed in Daikon at high humidity, there was
no indication that leaf diffusion resistance or plant water conductance were affected. Protoplasts from the cultivar Daikon
responded to elicitin by H+ uptake and K+ release, with maximal response at 300 pM. The response was eliminated by K252a or staurosporine. Daikon protoplasts also
showed transient uptake/secretion of Ca2+ on elicitin addition. Protoplasts from White Icicle gave neither of these responses. Both Daikon and White Icicle phenotypes
could be transferred to progeny of Daikon-White Icicle crosses and in the F2 generation three phenotypes, including a null,
segregated. Only those F2 plants which exhibited the Daikon phenotype produced protoplasts which responded to elicitin.
Received: 13 May 1997 / Accepted: 27 August 1997 相似文献