Trypsin Inhibitors during Germination of Vigna sinensis Seeds

The trypsin inhibiting activity of cotyledonary extracts of serido beans (Vigna sinensis) falls continuously during germination to a value which represents 5 % of the value for the dry seed. The specific activity is constant over the first three days and then decreases, reaching a level at the seventh day of germination which represents 20 % of the initial value. It is also shown that the axial parts control the disappearance of the trypsin inhibiting activity of the cotyledons. The results presented here seem to indicate a role for these substances in the process of germination.     

Proteinase Inhibitors in Plant Seeds

The proteinase inhibitors I (R-I) and III (R-III) isolated from Japanese radish seed were characterized in terms of their N-terminal amino acids, amino acid composition and reacting groups. The amino acid composition of two proteins differed from each other, while histidine, methionine and tryptophan contents were all low. N-Terminal amino acids of these inhibitors determined by Edman degradation were the same; valine.

By modifying free amino groups in the inhibitors with trinitrobenzenesulfonic acid, R-III was greatly inactivated in proportion to the modification of amino groups, but the activity of R-I was not affected.

However, modification of arginyl residues of R-I by cyclohexanedione reduced its activity. These results indicate that R-I is an arginine-type and R-III is a lysine-type inhibitor.     

Gibbercllins and Germination Inhibitors in Viable and Non-viable Seeds of Peanut (Arachis hypogea L.)

Gibberellins and germination inhibitors were studied in viableand non-viable seeds of peanut. More acidio and basic germinationinhibitors were present in non-viable than in viable seeds.Loss of viability is associated with the presence of inhibitorsand absence of gibberellin-like substances. Germination inhibitorsincluded compounds which co-chromatographed with abscisic acid.     

Growth and Germination Inhibitors in Hog-weed

Properties of a glutathione transport system in T. ferrooxidans strain AP-44 were investigated using a reduced form of ³⁵S-glutathione (³⁵S-GSH). About 71.2% of the total radioactivity taken up into the cells was distributed in the cytosol fraction. The amount of GSH taken up into the cells was in proportion to the amount of ferrous iron oxidized. However, a high concentration of silver ions (50 mm), which completely inhibited an iron-oxidizing activity, did not inhibit the GSH transport. The results suggest that GSH was transported by using a proton electrochemical gradient formed across the cytoplasmic membrane. Since growth inhibition by silver nitrate was decreased by the addition of GSH to both silver ion sensitive-cells and resistant-cells, the GSH transport system may play some role in the silver ion resistance mechanism of the bacterium.     

Germination Preventing Mechanisms in Iris Seeds

The different germination behaviour of the seeds of two irises,Iris lorteti and I. atropurpurea was found to be due to thedifferent mechanical resistance of the integument, at the micropylarend, to radicle protrusion. A pressure of 135 atm was necessaryin l. lorteti seeds for radicle protrusion, while in I. atropurpurea77 atm was sufficient. In contrast Pancratium maritimum requireda pressure of only 10 atm. The outer integument of seeds ofI. lorteti was found to contain a compound which was toxic tothe germinated embryo but did not act as a germination inhibitor.Extracts of the endosperm also had a slight germination inhibitingeffect. An interaction between this weak inhibitor and the effectof the testa could not be ruled out completely. A test assayfor germination using excised embryos was developed. A methodfor germination of Iris seeds, by cutting off the outer integumentat the micropylar end, was developed and is being exploitedcommercially. Iris lorteti, Iris atropurpurea, germination, germination inhibition, embryo culture, seed coat mechanical resistance     

Allelopathic Inhibitors in Seeds of Hevacleum laciniatum

Biological inhibitors present in the dry seeds of Heracleum laciniatum Horn have been studied by means of thin layer chromatography and various bioassays. The ethylacetate fraction of methanol extracts contained three main groups of inhibitors having the following R values when chromatographed on silica gel with chloroform: (1) 0.60–0.80; (2) 0.20–0.40; (3) 0.0–0.10. The group (1) inhibited lettuce seed germination and root growth, elongation of Avena first internode segments, growth of the fungus Cladosporium cucumerinum, and it caused leakage of betacyanin from red beet tuber slices. The groups (2) and (3) had no activity in red beet betacyanin leakage test, but they were inhibitory in the other bioassays used. The group (3) were generally less active than the group (2). The group (2) contained the furanocoumarins pimpinellin, bergapten, isobergapten and angelicin. Inhibitors present in the groups (1) and (3) have not been identified. Effects of five synthetic furanocoumarins (pimpinellin, bergapten, isobergapten, isopimpinellin, sphondin) on lettuce seed germination and Cladosporium growth were investigated. Pimpinellin was inhibitory to Cladosporium growth, and lettuce seed germination was inhibited by pimpinellin and sphondin.     

Rhythmic Behavior in Germination of Cocklebur Seeds

Non-dormant, lower seeds of cocklebur (Xanthium pensylvanicum Wallr.) germinated with unimodal flush after 20 and 36 h from the start of water imbibition at 33 and 23°C, respectively. At 28°C, however, germination occurred bimodally, the time of each peak coinciding with that at 23 and 33°C. This type of germination behavior was induced even at 33°C, when the seeds were contacted with some osmotica. Further, the application of different osmotica at 28°C caused a rhythmic multimodal germination with a period of about 16 h. It was suggested that an endogenous rhythmicity may be involved in the control of cocklebur seed germination.     

Germination Behaviour of Solanum nigrum Seeds

Sucrose has been found in the apoplast of bean stems at a concentrationof 25–60 mM with an axial concentration gradient in theappropriate direction for Munch translocation. Removal of theepidermis from a 50 mm length of stem enabled the washout oflabelled photosynthate from the apoplast. The rate of labelwashout was strongly dependent on temperature, and the rateincreased on blockage of phloem pathways to the main sink forthat assimilate. Washout did not reduce when the bathed tissuewas plasmolyzed. We propose that sucrose is unloaded from thephloem into the apoplast, and a sucrose concentration is maintainedthere by a balance of sucrose uptake into sink tissue or reloadinginto the phloem. It is proposed that the apoplastic pool ofphotosynthate can act to buffer sudden changes in phloem contentswhen there are rapid changes in source-sink configuration. Key words: Sucrose, Phaseolus vulgaris, Apoplast, Phloem unloading     

Thermoperiodism Mechanism in the Germination of Cocklebur Seeds

In thermoperiodic germination of secondarily dormant cocklebur(Xanthium pennsylvanicum Wallr.) seeds, the extent of electronflow through the CN-sensitive, cytochrome path and the CN-resistant,alternative path differred in the cool and warm phases. Thecool phase triggered active engagement of the alternative pathduring the subsequent warm phase, and this led to an increasein the ratio of the alternative path flux to the cytochromepath flux. The cool and warm phases had different functionsin adenylate metabolism. The former acted mainly in the productionand accumulation of ATP, whereas the latter supplied ADP and,especially, AMP. Thus an increasing number of sequential thermoperiodiccycles augmented the size of the adenylate pool and the energycharge, both of which may be necessary for germination to takeplace. (Received September 16, 1981; Accepted November 5, 1982)     

Germination of Seeds in the Shadow of Plants

An attempt to prove the ecological significance of red-far red control mechanisms in seed germination was made. The seeds of 30 species were exposed beneath the plant canopies. All the normally light-stimulated seeds, and also seeds of 14 (out of 19) “insensitive’ species and seeds of 1 (out of 4) light-inhibited species, were inhibited or significantly retarded in their germination, as compared with seeds exposed to diffuse light in an artificial construction. Further experiments with “insensitive’ seeds of Lactuca sativa L. cv. Cud Vorburgu showed that after prolonged plant-shadow treatment the seeds became light-sensitive in the usual phytochrome-mediated manner. Seeds exposed under the plant canopies during a few days were extremely sensitive to red or white light, but this sensitivity diminished slowly in the course of treatment. The spectral composition of light filtered through the leaves shows great preponderance of far red radiation. The red-far red reversion can be simply obtained with the natural light and a leaf. In open stands bright weather retards considerably the germination of lettuce, cloudy weather brings about full germination. Some considerations on the ecological significance of seed behaviour, particularly as connected with plant competition, are given.     

Germination of Echinochloa crus-galli (Barnyard Grass) Seeds under Anaerobic Conditions : Respiration and Response to Metabolic Inhibitors

Echinochloa crus-galli L. Beauv., a rice-field weed, can germinate and grow for extended periods of time in an anaerobic environment. Compared to pea, which does not germinate under anaerobiosis, the evolution of CO₂ in Echinochloa and rice is lower and the peak rate of CO₂ evolution is delayed when germinated without oxygen. The plants studied also differ with respect to their respiration ratio ([CO₂] N₂/[CO₂] air) and metabolism used during the early stages of germination. Echinochloa does not increase its glycolytic rate under anaerobiosis, whereas pentose phosphate pathway activity appears to increase during the first 40 to 50 hours of germination.

Based on its response to metabolic inhibitors (NaF, dinitrophenol, and malonate), anaerobic metabolism in Echinochloa proceeds primarily through glycolysis, with partial operation of the tricarboxylic acid cycle and little or no oxidative phosphorylation. Also, Echinochloa is sensitive to CN during aerobic germination, whereas rice appears to be able to shift to CN-insensitive electron transport. Finally, the effectiveness of cyanide and azide on inhibiting germination of Echinochloa in N₂, but not CO, suggests that cytochrome oxidase is not used to reoxidize pyridine nucleotides in the absence of oxygen. The possible existence of an alternate electron acceptor is discussed.

     

榛树种子的休眠和萌发

鉴定榛子各部分浸提液的结果显示 ,果皮、种皮及胚都存在导致休眠的抑制物质 ;榛树果实有一定的吸水性 ,据此推测种子休眠可能不是因果皮的不透水性造成 ;0 .5、2、5mg·L-16 BA可以解除种子休眠 ,促进萌发。     

‘勐海大叶茶’种子萌发特性

以大叶茶品种‘勐海大叶茶’ （Camellia sinensis var. assamica cv. Menghai Dayecha） 种子为材料,进行种子萌发特性的初步研究。研究发现,种皮对‘勐海大叶茶’种子的萌发存在一定的作用,含水量较高时,人为破除种皮有助于种子的萌发,随着含水量的降低,人为破除种皮反而降低了种子的萌发率。‘勐海大叶茶’种子的最适萌发温度为30℃,15℃以下时萌发率较低,容易发生低温伤害,变温处理对提高种子萌发率的效果不明显。基质对大叶茶种子萌发的影响不明显,四种不同种植基质条件下,种子的萌发率趋于相同水平,证明基质类型并非影响种子萌发的关键因子。     

Endogenous Inhibitors and Germination of Beta vulgaris

The nature and importance of endogenous germination inhibitorsin rubbed triploid monogerm sugar beet fruits were studied.Experimental evidence suggests that germination inhibitors donot play an important role in the prevention of germinationof rubbed fruits. Putative inhibitory compounds known to occurin sugar beet extracts were found to have little effect on germination.Measures to leach out water soluble compounds also had littleeffect on germination. Concentrated fruit extracts were foundto inhibit the germination of sugar beet seeds by virtue oftheir osmotic potentials, and this was related to the salt contentof the fruit extracts. However, a positive relationship wasfound between salt content and the original germination of thefruit lines. This relationship could have important consequencesfor assessment of fruit maturity and subsequent germinationbehaviour at harvest. The causes of poor germination in rubbedfruit lie not in the presence of inhibitory compounds in thefruit coat but in some other property of the fruit. Key words: Germination, Sugar beet: Inhibitors     

三裂叶野葛种子的休眠及萌发（简报）

２０mg.L^-1激动素（ＫＴ）浸种的三裂叶野葛种子萌发效果最佳,萌发率达７５％,用石英砂研靡破种皮后,再以２０mg.L^-1ＫＴ浸种的三裂叶野葛种子的萌发率达到９５％,提早５d萌发。根据种子抑制物实验的结果认为,三裂叶野葛种子的种皮和种仁中可能存在抑制种子萌发的物质。     

Germination and Dormancy in Immature and Fresh-mature Lettuce Seeds

The effects of red light, far-red light, Gibberellin A₃, andethephon were studied on the germination of lettuce seeds cv.Grand Rapids harvested at different stages of development. Seeds did not become capable of germination until 8 days afteranthesis. Red light promoted seed germination from the age of8–9 days following anthesis up to the newly mature stage.Ten or 11 days following anthesis, a large percentage of seedsbecame capable of germination in the dark and therefore couldbe considered not dormant. They were affected by far-red light,but less so than the mature seeds. The effect of light on the germination of developing seeds appearedto be similar to the known light effect on mature lettuce seedgermination. Gibberellin A₃ and ethephon had no effect on immatureand fresh seed germination. Lactuca sativa L., Lettuce, germination, dormancy, red light, far-red light, gibberellin A₃, ethephon     

Observations on Germination and Acetylcholinesterase Activity in Wheat Seeds

In the above article Fig. 1 appeared incorrectly; it shouldhave appeared as below:     

Observations on Germination and Acetylcholinesterase Activity in Wheat Seeds

Wheat seeds treated with organophosphorus insecticides exhibitdelayed germination both in the laboratory and in the field.Since (i) organophosphorus compounds inhibit cholinesteraseenzymes in animals and (ii) acetylcholine and cholinesterasehave been reported to occur in some plants, the hypothesis waspropounded that organophosphorus insecticides inhibit cholinesteraseactivity during cereal seed germination. Using biochemical andphysiological techniques, this hypothesis was tested in thelaboratory on wheat seeds germinated with and without the organophosphorusinsecticide, chlorfenvinphos. Evidence is presented for in vitroactivity of acetylcholinesterase in wheat seedlings and inhibitionof this activity by the insecticide. The possibility is discussedof a link between delayed germination and anti-cholinesteraseactivity of organophosphorus insecticides Wheat seeds, Triticum aestwum L., acetylcholinesterase, electrophoresis, germination, assay     

防风种子发芽特性及促进发芽的试验研究

防风种子发芽率和发芽势均较低,其主要原因包括个体之间的差异及物种特性。种子发芽率较低首先表现在个体发芽率上的差异,试验所用15株防风发芽率从28.0%到92.0%,从整体 上表现发芽率较低。防风本身发芽率低,由于物种因素,种子刚刚采收后的休眠,个体之间解除休眠时间和进入衰老的时间不一致,致使所有的种子不能全部在同一时间进入发芽高峰,同时,防风发芽的启动日有所差异,15株防风启动日和发芽持续时间相差均为两周以上。采用5~50 mg·kg^-1 GA、1~10 mg·kg^-1 6-BA、1%KNO₃和3%H₂O₂可提高休眠防风种子的发芽率,GA、6-BA可除防风种子的休眠,而1% KNO₃和3% H₂O₂对解除休眠的种子无明显影响。采用多种微量元素,即10~100 mg·kg^-1 Mn²⁺、10 mg·kg^-1 Cu²⁺和1 mg·kg^-1 Mo对种子进行处理可显著提高防风种子的发芽率,提示在植株绿果期喷施该类元素也可提高防风种子的发芽率。采用GA、NAA处理幼果,也可以提高种子的发芽率。