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71.
The response of fruiting or deblossomed trees to water stress such as drought or flooding was investigated in six semi open-top
cuvettes each containing one apple (Malus domestica Borkh. cv. Golden Delicious) tree. Xylem water potentials of leaves dropped from -1.2 to -4.1 MPa within 7 d of drought,
the effect being enhanced by fruiting. Apple trees without fruits showed smaller reductions in net photosynthetic rate (P
N
) and dark respiration rate (R
D
) after 2 d of drought and hence more positive carbon balances relative to fruiting trees. Flooding for 4 d had a more pronounced
effect on P
N
than on transpiration, resulting in a reduced water use efficiency (WUE). This reduction in WUE was greater in the non-fruiting
trees. Flooding reduced P
N
of the whole apple canopies irrespective of fruiting; aple trees without fruits increased R
D
resulting in a less positive carbon balance relative to fruiting trees. Fruiting increased the sensitivity to drought of
apple trees (R
D
and P
N
), but decreased their sensitivity to flooding (R
D
and WUE), suggesting different adaptation mechanisms for the two forms of water stress.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
72.
Xuetong Fan James P. Mattheis John K. Fellman Max E Patterson 《Physiologia plantarum》1997,101(2):328-332
Apple fruits ( Malus domestica Borkh.) were harvested from 24 to 136 days after full bloom (DAFB) and endogenous jasmonic acid was analyzed by GC-MS. There were two isomers of jasmonic acid in apple fruit with a ratio of 37:63 ( cis:trans ). The cis:trans ratio remained relatively constant throughout this period of fruit development. The endogenous jasmonic acid concentration was 138 ng g−1 fresh weight 24 DAFB and decreased as fruit developed. Changes in jasmonic acid concentration were coincident with those of respiration, ethylene production, and anthocyanin accumulation in patterns consistent with the reported responses to exogenous jasmonates. Possible roles for jasmonic acid during early fruit development are discussed. 相似文献
73.
Summary The ventral organs of the cephalic lobes of the house fly larvae, Musca domestica L., were studied by scanning and transmission electron microscopy. Four sensilla were found. Three of them are each innervated by a single dendrite whose ending possesses a tubular body and communicates to the exterior through an opening. These sensilla are assumed to be mechanoreceptors. The 4th sensillum is supplied by 2 bipolar neurons with the unbranched dendritic tips (without tubular bodies) exposed to the exterior through a single opening and is probably a contact chemoreceptor.This research was supported in part by the Office of Naval Research and NIH Training Grant ES-00069. Paper no. 3724 of the North Carolina State University Agricultural Experiment Station journal series. 相似文献
74.
New information is reported on the parasitism of Heterotylenchus autumnalis upon its principal known host, Musca autumnalis. Black to brown spots are produced on the cuticle of all infected host larvae where the nematode penetrated. The principal damage to the host is castration of the female. In laboratory tests nematode larvae were not infective and did not leave the hosts before the female fly was 1 1 days old. Nematode larvae removed from infected male flies infected other hosts, but it is believed that in nature these larvae are unable to leave the host. 相似文献
75.
【目的】探究香樟Cinnamomum caphora果实精油、天竺桂Cinnamomum pedunculatum叶精油和龙柏Sabina chinensis var.chinensis叶精油对家蝇Musca domestica成虫的熏蒸活性,比较这3种植物精油以及混配精油对家蝇的毒力效果,为植物源灭蝇剂的开发提供理论依据。【方法】利用水蒸汽蒸馏法提取植物精油,采取三角瓶密闭熏蒸法测试植物精油及其混剂对家蝇5日龄成虫的熏蒸毒性和击倒作用。【结果】3种植物精油对家蝇的LC50值(致死中浓)分别为5.28,16.86和14.54μg/cm3。LC90熏蒸剂量下,对家蝇的KT50值(击倒中时)分别为12.03,16.56和13.37 min。天竺桂叶精油和龙柏叶精油混配后对家蝇有增效作用,二者的LC50值配比为9∶1时,增效作用极为显著,共毒系数高达367.95。【结论】香樟果实精油对家蝇成虫有很好的熏杀和击倒作用,龙柏叶精油次之,天竺桂叶精油效果最差。天竺桂叶精油和龙柏叶精油混配后对其对家蝇成虫的熏蒸毒性有增效作用。3种植物精油具备开发环保灭蝇剂的潜力,可深入研究。 相似文献
76.
Atkinson Christopher J. Policarpo Michaelangelo Webster Anthony D. Kuden Ayzin M. 《Plant and Soil》1999,206(2):223-235
The drought tolerance of the commercial apple ( Malus domestica Borkh.) rootstocks M9, M26, M27 and MM111, and some new selections
from the rootstock breeding programme at HRI-East Malling (AR69-7, AR295-6, AR360-19, AR486-1 and AR628-2), was assessed using
potted, glasshouse-grown, unworked rootstocks. After an initial period of growth under well-watered conditions the amount
of irrigation was gradually reduced, for some treatments, to simulate natural drying in the soil. At the end of a six-month
growth period, the rootstocks were harvested and the production of dry matter and its partitioning to various plant parts
determined. The rootstocks exhibited large differences in shoot and root dry matter, and root length but not all the rootstocks
showed declines in root mass or length in response to the droughting treatment. The dwarfing rootstocks tended to have smaller
amounts of both coarse (>2 mm diameter) and fine roots (<2 mm diameter), than the more vigorous rootstocks. Irrespective of
rootstock or irrigation treatment there was a close linear relationship between coarse and fine root. There was also no change
in the length/weight relationship for fine roots irrespective of rootstock or irrigation treatment, i.e. 42 m of fine root
weighed 1 g dry weight. In some cases the amount of root produced could be directly correlated with the rootstock known potential
to control scion vigour, but this was not true for all the rootstocks examined. The absence of this relationship was particularly
evident in some of the new selections of rootstock. The possible causes for these differences, compared with commercially
used rootstocks, is discussed in relation to the origin and parentage of the rootstock selections. Despite this lack of a
root length/vigour relationship, the amount of dry matter partitioned to shoot growth reflected the rootstocks' known vigour.
The different responses of these rootstocks to drought are discussed along with their implications for understanding the mechanisms
by which rootstocks are thought to dwarf scion shoots. 相似文献
77.
Quantification of endogenous gibberellins in exudates from fruits of Malus domestica 总被引:2,自引:0,他引:2
In exudates from developing apple fruits GA1, GA3, GA4, GA7, GA20 and GA34 could be identified and subsequently quantified by LC-ESI-MS selected-ion-monitoring analyses on the basis of internal standards. This is the first evidence obtained by mass spectrometrical analysis which demonstrates export of endogenous GAs from the fruits during the period when flower induction occurs. The observed differences in GA4 export are discussed in connection with biennial bearing. 相似文献
78.
抑卵激素对家蝇卵巢周期性发育的调控 总被引:3,自引:1,他引:2
抑卵激素是调控家蝇Musca dorncstica vicina卵巢周期性发育的关键因子之一。在家蝇中,当第一个周期的卵母细胞处于卵黄发生期或卵黄发生后期时,其第二个周期的卵母细胞的发育不进入卵黄发生期。本文建立了家蝇抑卵激素的生物测定方法,即用一对卵巢提取物注射1头羽化后12h家蝇,并在羽化后60h观察卵母细胞的发育及卵黄蛋白的沉积情况。抑卵激素的作用首先是延缓了卵母细胞在卵黄发生前期的发育;其次,抑卵激素抑制脂肪体中卵黄蛋白的合成,导致血淋巴中卵黄蛋白含量的下降,从而抑制了卵母细胞的发育。抑卵激素并不抑制卵母细胞对卵黄原蛋白的摄取。卵发育神经激素可以颉抗抑卵激素的抑制作用。抑卵激素无种属特异性。 相似文献
79.
Induction of embryogenesis from isolated apple microspores 总被引:2,自引:0,他引:2
We report, for the first time, the induction of embryogenesis and plant formation from isolated apple (Malus domestica Borkh.) microspores in vitro. Different isolation techniques were tested and an optimized protocol was elaborated. Furthermore,
the influence of the induction medium and starvation treatment, using different starvation material, temperatures and time,
were studied. In addition to embryo induction, the number of multicellular structures per divided microspores was found to
be a suitable parameter of assessment and could be used in earlier stages during microspore culture. Although the number of
embryos induced in these first experiments is low, the best frequency of embryo induction was shown to be at least twice as
efficient as that obtained by anther culture.
Received: 9 September 1998 / Revision received: 22 December 1998 / Accepted: 12 January 1999 相似文献
80.
家蝇(Muscadomestica)幼虫以营养成分全、蛋白质含量高而逐渐引起人们重视,具有很高的开发利用价值和广阔的前景。系统动力学的发展为研究复杂系统提供了有效途径[1,2]。本文试用系统动力学方法建立家蝇幼虫开发生态工程仿真模型,以期解决这一研究... 相似文献