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51.
Fruit Development and Structure in Some Indian Bamboos   总被引:2,自引:0,他引:2  
Fruit structure and development of seven species belonging tofive genera of Indian bamboos are described. The fruit in fourspecies is a caryopsis typical of the family Poaceae. The ovuleis bitegmic; the outer surface of the cells of nucellar epidermisbecomes cutinized and forms the seed coat. Three species beara fleshy fruit with a unitegmic ovule. In a mature fruit theendosperm is either completely absorbed by the embryo or ispresent only in small quantity. The developing embryo comesin direct contact with the fruit wall due to the disintegrationof the nucellus and integument. The embryo is covered by a thickbrown mat from the disorganized cells of the inner layers ofthe fruit wall. Poaceae, Bambusoideae, Bambusa, Dendrocalamus, Melocalamus, Ochlandra, Pseudostachyum (fleshy fruits), fruit wall  相似文献   
52.
花生种子含油量的遗传分析   总被引:3,自引:1,他引:3  
花生是重要的油料作物,对花生种子含油量进行遗传分析具有重要意义.本研究以高油花生新品种SPI056(P1)和低油花生新品种花育17(P2)及其杂交组合的F1、F2群体为材料,应用P1、P2、F1和F2 4个世代的数量性状主基因+多基因混合遗传模型联合分离分析方法,对种子含油量进行了遗传分析.结果表明:花生种子含油量由两对加性-显性-上位性主基因+加性-显性多基因共同控制,主基因遗传率为72 55%.  相似文献   
53.
电刺激猫小脑问位核和顶核可以影响下丘脑外侧区神经元的电活动,其中有一些神经元是葡萄糖敏感神经元.这一结果揭示小脑不仅具有经典的躯体运动调节功能,同时也可以通过小脑-下丘脑通路参与机体非躯体活动的调节.  相似文献   
54.
55.
Apomixis and Polyembryony in the Guggul Plant, Commiphora wightii   总被引:2,自引:0,他引:2  
The present report is a part of our study on the reproductivebiology of a traditional Indian medicinal plant,Commiphora wightii,a source of guggul steroids. Field examination showed a predominantlylarge number of isolated and groups of female individuals. Onlyone andromonoecious and two exclusively male plants were recorded.Female plants set seed irrespective of the presence or absenceof pollen. Hand-pollination experiments and embryological studieshave confirmed the occurrence of non-pseudogamous apomixis,nucellar polyembryony and autonomous endosperm formation forthe first time in this plant, which is presently threatenedby over-exploitation. Commiphora wightii ; autonomous endosperm; guggul; medicinal plant; non-pseudogamous apomixis; nucellar polyembryony  相似文献   
56.
Abstract:  Genera of Palaeontinidae (Insecta, Hemiptera: Cicadomorpha) are reviewed based on some newly-discovered material. An updated list of palaeontinid genera is provided. The genus Palaeontinopsis Martynov is assigned to Palaeontinidae incertae sedis . A new genus and species, Ningchengia aspera gen. et sp. nov., is described based on forewings and hindwings from the Middle Jurassic of Daohugou, China. Fletcheriana colorata Wang, Zhang and Fang and F . minuta Wang, Zhang and Fang are transferred to Suljuktocossus and Ningchengia respectively, resulting in Suljuktocossus coloratus comb. nov. and Ningchengia minuta comb. nov. Papilioncossus Wang, Ren and Shih, 2007 syn. nov. is considered to be a junior synonym of Eoiocossus Wang and Zhang, 2006 and Quadraticossus Wang and Ren 2007 syn. nov. is a junior synonym of Sinopalaeocossus   Hong, 1983 . The genus Fletcheriana is believed to represent a transition between Dunstaniidae and Palaeontinidae. This result is consistent with the previous view that Dunstaniidae is ancestral to Palaeontinidae. Furthermore, Suljuktocossus is a transitional genus between Fletcheriana and Cretaceous palaeontinids. The fusion of veins RP and M1 in the palaeontinid hindwings implies a change of the mechanism of flight and an improvement in flight ability. The presence of a reduced costal area and the rigid basal leading edge of the palaeontinid forewings suggest gain of lift.  相似文献   
57.
In situPCR on Plant Material with Sub-cellular Resolution   总被引:4,自引:0,他引:4  
JOHANSEN  BO 《Annals of botany》1997,80(5):697-700
In situPCR and reverse transcribedin situPCR have been testedon leaves of sugar cane fixed in FAA, 4% PFA or 2% PFA+2.5%GA.In situPCR amplification of the gene coding for ribulose-1,5-bisphosphatecarboxylase/oxygenase (rbcL) was successfully performed followingall three fixation protocols. As expected the PCR product wasrestricted to the plastids of all cells. Reverse transcribedinsituPCR was performed onrbcL mRNA and in this case the PCR productwas restricted to the plastids of the bundle sheath cells. Thisis the first report ofin situPCR on plant material and onlythe second report ofin situPCR with sub-cellular resolution.InsituPCR onrbcL may prove to be a valuable positive control forfuturein situPCR studies on plant material.Copyright 1997 Annalsof Botany Company In situPCR; reversed transcribedin situPCR; rbcL; C4-plants  相似文献   
58.
NAIR, M. N. B. AND MOHAN RAM, H. Y., 1989. Vestured pits and vestured vessel member walls in some Indian dicotyledonous woods. The woods of 144 taxa belonging to 38 families of angiosperms were examined for vestured pits and vestured vessel member walls using scanning electron microscopy. Vestured pits are present in 66 taxa (belonging to ten families) and vestured vessel member walls occur in only six taxa (belonging to three families). In Ehretiaceae and Euphorbiaceae vestures are present only in certain vessel members. In Wrighlia tinctoria , perforation plates containing vestures have been observed in addition to the presence of vestured pits. A classification of vestured pits based on their morphology and distribution is proposed by us. In all the types of vestured pits, vestures are present on the margin of the outer pit aperture or on the pit chamber wall. Occasionally, they are present in the pit canal, on the margin and in the vicinity of the inner pit aperture and rarely over the inner walls of the vessel members. The functions of vestured pits are not clear, although several suggestions are made. Whether or not these structures affect wood processing is not presently understood. It appears that vestured pits and vestured vessel member walls have diagnostic rather than phylogenetic value.  相似文献   
59.
60.
Populations of carrot (Daucus carota) were raised over a widerange of densities (79–5763 plants m-2) to examine thedynamics of competition in terms of yield–density relationshipsand size variability, and to investigate the effects of nutrientsupply on competition. While the relationship between shootyield and density was asymptotic, the relationship between rootand total yield and density tended to be parabolic. For a giventime and density series the relationship between yield per unitarea and density could best be described by the model: y=wmD(1+aD)b wherey is the yield per unit area,D is density,wm, a andb arefitted parameters. The parameterswm anda increased over timebut nutrient availability affected onlywm. An extension of thebasic yield-density model is proposed to describe the dynamicsof the yield–density relationship over time: y=kD[1+cexp(-rt)]{1+  相似文献   
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