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121.
The amphibious plant species of intermittent aquatic habitats thrive both submerged and emerged. In order to outline the adaptive
characters of these two life forms photochemical efficiency of photosystem 2, leaf contents of chlorophyll (Chl) a and b, carotenoids (Car), anthocyanins (Ant), and UV-B absorbing compounds (UV-B abs), and root aerenchyma and arbuscular mycorrhizal
(AM) colonisation were studied in Glyceria fluitans, Gratiola officinalis, Ranunculus lingua, Teucrium scordium, Sium latifolium, Sparganium emersum, and Veronica anagallis-aquatica. Water level fluctuations did not exert a severe effect on photon harvesting efficiency. Submerged specimens had higher contents
of Car and Ant whereas higher contents of UV-B abs were found in emerged specimens indicating efficient protection against
the harmful effects of solar radiation. Roots of all species studied had extensive aerenchyma and were colonised by AM fungi,
which were significantly more abundant in emerged specimens. This is the first report on AM symbiosis in S. latifolium and S. emersum. 相似文献
122.
During growth and subsequent maturation, the distribution and formation of pigments in the inner pulp and in the outer region of the pericarp of ‘che 相似文献
123.
Sonny B. Ramaswamy Wai Keung Ma Gerald T. Baker 《Entomologia Experimentalis et Applicata》1987,43(2):159-168
When given a choice of cotton (host) and ground cherry (non host) in a close range situation, Heliothis virescens (F.), the tobacco budworm, depends primarily on contact chemoreception and mechanoreception, and not olfaction or vision, to discriminate between these two plant species for oviposition. Further, in the presence of a certain level of hairiness (the non-host plant, ground cherry, has short capitate hairs), the females are capable of discriminating between these two plants based on contact chemosensory cues, if at least one pair of tarsi is intact. The contact chemosensilla on the ovipositor do not seem to be important for this purpose. These results are discussed in relation to the sensory cues and receptors for oviposition in other Lepidoptera, especially moths.
Signaux et récepteurs sensoriels intervenant dans la ponte d'Heliothins virescens
Résumé Les différentes récepteurs sensoriels (chimique, mécanique et visuel) des femelles d'H. virescens ont été rendus inactifs par traitement à l'acide, antennotectomie ou peinture des yeux avec un enduit noir du type vernis à ongles, pour étudier le déterminisme sensoriel de la sélection des hôtes lors de la ponte; les papillons avainet le choix entre le coton (Gossypium hirsutum), sur lequel ils pondent normalement, et Physalis angulata sur lequel on n'observe pas de pontes dans la nature. Au laboratoire, à faible distance, le choix de H. virescens dépendait en premier lieu des mécanorécepteurs et des récepteurs chimiques dits de contact (gustatifs), et non de la vision ou de l'olfaction. En présence d'un certain niveau de pilosité (P. angulata possède de courts poils capités), les femelles choisissent les plantes en fonction de la perception chimique dite de contact (gustation) tant qu'une paire de tarses reste intacte. Les sensilles chimiques de l'ovitube ne semblent pas jouer un rôle important à cet égard. La discussion a examiné ces résultats à la lumière des processus sensoriels utilisés par d'autres papillons.相似文献
124.
In addition to chlorophylls a and b, β-carotene, lutein, violaxanthin and neoxanthin, leaves of tobacco (Nicotiana tabacum L. cv. Virginia Gold) contain antheraxanthin in some harvests. In lower leaves, chlorophylls decreased more rapidly than carotenoids during senescence, but both types of pigment decreased at equal rates in upper leaves. The chlorophyll a:b ratio decreased only in post-mature leaves. Total carotenoid decreased with age, with the relative proportion of β-carotene increasing in lower leaves. Seasonal influences rather than age of leaf determines whether antheraxanthin is present. No esterified xanthophylls were found in senescent leaves. 相似文献
125.
Mujeebur Rahman Khan Ziaul Haque M. Arshad Anwer M. Mahmud Khan 《Archives Of Phytopathology And Plant Protection》2013,46(1):99-109
The effect of inoculation with Pythium aphanidermatum was studied on total phenol (TP), salicylic acid (SA), chlorophylls and carotenoid contents of leaves and plant growth characteristics of five tobacco cultivars, namely RK-10 P3, RK-12 P3, RK-13 P4, RK-18 P8 and RK-26 P3, to assess cultivar response at biochemical and morphological levels. Root rot measured at 0–5 scale was 2.66 on cv. RK-10 P3, followed by 2. 33 on cv. RK-18 P8, 1.33 on cv. RK-26 P3 and 1.0 on cv. RK-13 P4. The cv. RK-12 P3 did not develop measurable root rot. The rhizosphere population of root rot fungus increased over time, being highest on the cv. RK-10 P3 (P ≤ 0.001), followed by cvs. RK-18 P8, RK-26 P3, RK-13 P4 and RK-12 P3. Inoculation with the fungus resulted in 5% (cv. RK-10 P3), 10.3% (cv. RK-18 P8, P ≤ 0.05), 10.9% (cv. RK-26 P3, P ≤ 0.05), 16.4% (cv. RK-13 P4, P ≤ 0.01) and 41.5% (cv. RK-12 P3, P ≤ 0.001) increase in the TP content of leaves. SA concentration in tobacco leaves increased marginally (0.8%–3%) in cvs. RK-10 P3, RK-18 P8 and RK-26 P3, but considerably (16%–17%, P ≤ 0.01) in cv. RK-13 and RK-12 P3 in comparison to uninoculated plants. Total chlorophyll content of leaves in response to inoculation with P. aphanidermatum decreased by 27% and 23% in tobacco cvs. RK-10 P3 and RK-18 P8 (P ≤ 0.001) and 17.6 (P ≤ 0.01) and 10.6% (P ≤ 0.05) in cv. RK-26 P3 and RK-13 P4, respectively. Reduction in chlorophylls a and b was 20% and 15% in cv. RK-10 P3 and 20% and 11% in cv. RK-18 P8. Total carotenoid contents of tobacco leaves decreased significantly in cvs. RK-10 P3 and RK-18 P8 (P ≤ 0.05). Significant and greater decrease in plant growth variables was recorded in the cultivars in which increase in TP and SA was lower and decrease in chlorophyll and carotenoids was greater. This study has revealed that greater synthesis of TP and SA may provide resistance in tobacco plants against P. aphanidermatum. The cv. RK-12 P3, in which greatest increase in the SA (17%) and TP (41.5%) was recorded, did not exhibit a significant decrease in plant growth variables and leaf pigments (P ≤ 0.05). 相似文献
126.
以4年生‘岑软2号’油茶(Camellia oleifera ‘Cenruan 2’)的半木质化枝条为材料,采用不同生长调节剂处理插穗,测定扦插生根过程中插穗过氧化物酶(POD)、可溶性蛋白质及叶绿素含量的动态变化。结果表明,扦插后不同时间的POD活性、可溶性蛋白质和叶绿素含量均有极显著差异(P<0.01),且呈规律性变化,POD活性呈“上升–下降–上升–下降”双峰变化趋势,可溶性蛋白质呈“上升–下降–上升”变化趋势,叶绿素含量呈“下降–上升–下降–上升”变化趋势;与对照相比,经生长调节剂处理的插穗POD活性、可溶性蛋白质和叶绿素含量的峰值显著提高,说明其促进油茶插穗生根。 相似文献
127.
本研究旨在明确我国北方苜蓿重要害虫——牛角花齿蓟马Odontothrips loti触角感器类型、形态特征及分布特点。利用扫描电镜观察牛角花齿蓟马雌、雄成虫触角的超微结构,比较雌、雄虫之间的差异。结果表明:牛角花齿蓟马雌虫触角长度(314.42±7.21 μm)明显较雄虫(260.58±5.69 μm)长,除柄节和第I鞭节外,其他各节雌虫均较雄虫粗大。牛角花齿蓟马成虫触角感器类型共有7种,即Bhm氏鬃毛(BB)、刺形感器(SChI, SChII)、锥形感器(SBI, SBII, SBIII)、钟形感器(SCa)、腔锥形感器(SCo)、腔形感器(SCav)和毛形感器(ST),雌虫触角上述7种类型感器均有分布,而雄虫触角上未发现腔形感器。牛角花齿蓟马成虫触角感器在类型、形态特征及分布方面表现雌、雄个体差异。本研究为深入探究牛角花齿蓟马触角感器的嗅觉通讯机制提供形态学基础。 相似文献
128.
Mechanosensory transduction underlies the perception of touch, sound and acceleration. The mechanical signals exist in the environment are resensed by the specialized mechanosensory cells, which convert the external forces into the electrical signals. Hearing is a magnificent example that relies on the mechanotransduction mediated by the auditory cells, for example the inner‐ear hair cells in vertebrates and the Johnston's organ (JO) in fly. Previous studies have shown the fundamental physiological processes in the fly and vertebrate auditory organs are similar, suggesting that there might be a set of similar molecules underlying these processes. The molecular studies of the fly JO have been shown to be remarkably successful in discovering the developmental and functional genes that provided further implications in vertebrates. Several evolutionarily conserved molecules and signaling pathways have been shown to govern the development of the auditory organs in both vertebrates and invertebrates. The current review describes the similarities and differences between the vertebrate and fly auditory organs at developmental, structural, molecular, and transportation levels. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 109–130, 2015 相似文献
129.
Batista-Santos P Lidon FC Fortunato A Leitão AE Lopes E Partelli F Ribeiro AI Ramalho JC 《Journal of plant physiology》2011,168(8):792-806
Environmental constraints disturb plant metabolism and are often associated with photosynthetic impairments and yield reductions. Among them, low positive temperatures are of up most importance in tropical plant species, namely in Coffea spp. in which some acclimation ability has been reported. To further explain cold tolerance, the impacts on photosynthetic functioning and the expression of photosynthetic-related genes were analyzed. The experiments were carried out along a period of slow cold imposition (to allow acclimation), after chilling (4 °C) exposure and in the following rewarming period, using 1.5-year-old coffee seedlings of 5 genotypes with different cold sensitivity: Coffea canephora cv. Apoatã, Coffea arabica cv. Catuaí, Coffea dewevrei and 2 hybrids, Icatu (C. arabica × C. canephora) and Piatã (C. dewevrei × C. arabica). All genotypes suffered a significant leaf area loss only after chilling exposure, with Icatu showing the lowest impact, a first indication of a higher cold tolerance, contrasting with Apoatã and C. dewevrei. During cold exposure, net photosynthesis and Chl a fluorescence parameters were strongly affected in all genotypes, but stomatal limitations were not detected. However, the extent of mesophyll limitation, reflecting regulatory mechanisms and/or damage, was genotype dependent. Overnight retention of zeaxanthin was common to Coffea genotypes, but the accumulation of photoprotective pigments was highest in Icatu. That down-regulated photochemical events but efficiently protected the photosynthetic structures, as shown, e.g., by the lowest impacts on Amax and PSI activity and the strongest reinforcement of PSII activity, the latter possibly reflecting the presence of a photoprotective cycle around PSII in Icatu (and Catuaí). Concomitant to these protection mechanisms, Icatu was the sole genotype to present simultaneous upregulation of caCP22, caPI and caCytf, related to, respectively, PSII, PSI and to the complex Cytb6/f, which could promote better repair ability, contributing to the maintenance of efficient thylakoid functioning. We conclude that Icatu showed the best acclimation ability among the studied genotypes, mostly due to a better upregulation of photoprotection and repair mechanisms. We confirmed the presence of important variability in Coffea spp. that could be exploited in breeding programs, which should be assisted by useful markers of cold tolerance, namely the upregulation of antioxidative molecules, the expression of selected genes and PSI sensitivity. 相似文献
130.