Effects of polyamines on the early development of cystocarps,spore release,survival,and germination rate of Gracilariopsis lemaneiformis

Three polyamines(PAs)(spermidine(Spd),spermine(Spm),and putrescine(Put))were used as growth regulators to the marine macroalgae Gracilariopsis lemaneiformis and to female gametophyte and reproductive tissues(cystocarps were constructed),which led to early maturation of cystocarps and spore release.Laboratory cultivation revealed that exogenous PA application accelerated the development of cystocarps,and the mean sporeling growth rate was 20%–50%/d during the initial week of cultivation.The spore count(SC),survival rate(SR),and germination rate(GR)of G.lemaneiformis showed different responses to PA(10-6 mol/L and 10-3 mol/L)treatments under different temperatures(18,26,and 34℃),light intensities(30,60,and 90μmol photons/(m^(2)·s)),salinities(25,30,and 35),and nutrient levels(25꞉2.5,50꞉5.0,and 75꞉7.5μmol/L NH4Cl꞉K2HPO4),and the optimal conditions were 26℃,light intensity of 60μmol/(m^(2)·s),salinity of 35,and nutrient level of 50꞉5.0μmol/L NH4Cl꞉K2HPO4.Under the optimum conditions,the SC per cystocarp increased by 82.38%,and the spore SR and GR increased by 33.07%and 46.44%,respectively.Each experiment lasted for 7 days,with the highest SC on Day 4 and plateauing on Day 7.The results indicate that PAs could promote the early maturation,spore release,survival,and germination of G.lemaneiformis under laboratory conditions.

Effects of Different Processing Methods on Germination Rate of Wada Alfalfa Seeds

[Objective] To find a processing method to increase germination rate of Wada alfalfa seeds. [Method] Five processing methods were used to treat Wada alfaffa seeds, including immersion in hot water, immersion in 98% concentrated sulfuric acid, immersion in 100 g/L potassium nitrate, immersion in hot water after rubbing seed capsule, immersion in 30% （ V~ V） hydrogen peroxide. After treatment, germination energy, germination rate, germination index and vitality index were detected. [ Result] The Wada alfaffa seeds immersed in 25℃ water for 25 min after rubbing seed capsule had the highest germination rate （81.3%）, followed by that of seeds immersed in 100 g/L potassium nitrate for 2 h, that of seeds immersed in 50℃ water, and that of seeds immersed in 30% hydrogen peroxide for 5 min in order. The worst germination appeared in the seeds im- mersed in 98% concentrated sulfuric acid. [ Conclusion] Immersion in 25℃ water for 25 min after rubbing seed capsule is the best method to increase germination rate of Wada alfaffa seeds.

Evaluation on Sixty-eight Rice Germplasms in Cold Tolerance at Germination Stage

Sixty-eight rice germplasms were used for cold tolerance evaluation at the germination stage in laboratory. Seeds of rice germplasms germinated at three different temperatures containing low temperature （constant 13°C for 28 days）, alternative temperature （a temperature cycle of 12 h at 20°C and 12 h at 23°C for 14 days） and control （constant 26°C for 7 days）. Analysis of variance revealed that temperature had a significant effect on germination rate, coleoptile length and radicle length. Germination rate was strongly affected by the low temperature and alternative treatments. Stress of low temperature at the germination stage on the tested rice germplasms caused a reduction in final germination rate and the lengths of coleoptile and radicle. The normal and healthy seeds began to germinate within 36 h after imbibition and germination were completed on the 7th day in the control, but delayed under the low and alternative temperature treatments. The low and alternative temperature treatments delayed the growth of coleoptile and radicle compared to the control, and the average lengths of coleoptile and radicule were strongly inhibited with the decreasing temperature in all of the tested germplasms. Taichung, a semi-dwarf, low amylose content and early maturing rice variety, showed a significantly higher germination rate at the three temperature treatments and its coleoptile length was significantly higher than other germplasms.

Nursery practice on seed germination and seedling growth of Dalbergia sissoo using beneficial microbial inoculants

Nursery practice using microbial inoculants was performed to find out the efficacy of the inoculants on seed germination and seedling growth of sissoo（Dalbergia sissoo Roxb.）.Microbial inoculants or effective microorganisms（EM） are a mixture of many different beneficial microorganisms in a solution.The seedlings were grown in a mixture of sandy soil and cowdung（3：1） kept in polybags with pouring EM solution at different concentrations（0.1%,0.5%,1%,2%,5% and 10%） before and after a week of sowing the seeds.Seed germination rate and growth parameters of seedlings were measured,such as,shoot and root length,vigor index,fresh and dry weight of shoot and root and total biomass increment.The nodulation status influenced by EM was also observed along with the measurement of pigment contents in leaves.The highest germination rate（69%） was observed in 2% EM treatment,followed by 67% and 65% in 1% and 5% EM.The highest shoot length（33.2 cm） was in 2% EM,whereas highest root length（26.3 cm） was in 1% EM.Both fresh and dry weights from shoot and root,were maximum（4.16 g and 1.57 g;2.12 g and 0.83 g respectively） in 2% EM and were significantly（p ≤ 0.05） different from control.Vigor index was highest（4071） in 2% EM,which was significantly（p ≤ 0.05） different from control.Total dry weight increment was highest in 2% EM treatment,followed by 1% and 5% concentrations of EM.Nodulation number was higher at very low（0.1%） concentration of EM solution but it normally decreased with the increase of EM concentrations.The contents of chlorophyll a,chlorophyll b and carotenoid were highest（60.11,17.05 and 42.48 mg·L1respectively） in 2% EM treatment and lowest（39.35,13.55 and 27.29 mg·L-1 respectively） in control treatment.Therefore,low concentration of EM（up to 2%） can be used for getting maximum seed germination rate and seedling development of Dalbergia sissoo Roxb.

Effect of seed treatment for laboratory germination of Albizia chinensis

Seeds of Albizia chinensis（Osb.） Merr. in addition to water were also treated with different treatments by incubating in ethyl alcohol, acetone, and petroleum ether at room temperature for different durations. Seed heat treatment was done at temperatures of 30, 40 and 60℃ for different durations up to 24 h. To overcome dormancy caused by the impermeable seed coat, seeds were nicked and also treated with concen- trated sulphuric acid for different durations. Seeds responded to treat- ments with sulphuric acid and nicking only. Treatment with sulphuric acid for 20 and 30 min showed maximum germination at all incubation temperatures as compared to untreated controls and seeds treated with sulphuric acid for 10 min and nicking. Seedling length was greatest from seeds treated with sulphuric acid for 20 and 30 min and incubated at 30 ℃. Seedling dry weight was highest from nicked seeds incubated at 20℃ The most favourable incubation temperature was 30 ℃ as evidenced from GR （germination rate index） and Gv （germination value）. After ascertaining the seed response and performance we recommend that seeds ofAlbizia chinensis be treated with sulphuric acid for 20 or 30 min and incubation temperature of 25 to 30℃.

Effects of Different Treatments on Seed Germination of Zanthoxylum nitidum(Roxb.)Seed

[Objectives]This study was conducted to improve the germination rate of Zanthoxylum nitidum(Roxb.)seeds and shorten the germination period.[Methods]Different germination beds,seed soaking temperatures,seed soaking time and culture temperatures were set to study the effects on seed germination of Z.nitidum.[Results]The germination rate on the filter paper germination bed was stable and it was easy for the control of humidity.The germination rate of seeds soaked in warm water at 50℃for 24 h was about 53.33%.The germination rate of seeds cultured at 25℃was as high as 91.98%.[Conclusions]This study provides a theoretical basis for seedling breeding and large-scale production of Z.nitidum.

Preparation of a Novel Highly Effective and Environmental Friendly Wheat Seed Coating Agent

A novel environmental friendly wheat seed coating agent was prepared from the natural polymer,biological pesticide,microfertilizer,microelements and other additives.The laboratory and field test results showed that it could enhance the yield up to 16% and reduce its input cost to 1/6 as compared with the conventional wheat seed coating agent.It is safe without causing any pollution and would have significant economic and environmental benefits.

In vitro culture of immature embryos from Koelreuteria bipinnata var. integrifoliola

For the mass production of Koelreuteria bipinnata var. integrifoliola with selected, hybrid or genetically engineered genotypes, one potentially desirable propagation strategy is based on embryo culture. The immature embryo development in vitro from K. bipinnata var. integrifoliola was studied under different conditions of embryo age, basic culture media and plant growth regulators. The results show that： 1） germination rate of grade 3 embryos in immature seeds with 0.6-0.8 cm diameter was 98.9%. The germination rate of grade 2 embryos in immature seeds with 0.4-0.6 cm diameter was 77,8% and the germination rate of grade 1 embryos in immature seeds with 0.4 cm diameter was 15.6%. 2） The amounts of macroelements in MS medium had no clear effect on the germination rate of immature grade 3 embryos and had a modest effect on plantlet growth, where the best medium was MS or 1/2 MS. The rates were all greater than 90%. 3） The germination rate of grade 3 embryos was greater than 87% when the medium contained a low concentration of NAA or no plant growth regulators at all and decreased markedly when BAP alone or BAP and NAA together were added to the media. We suggest that in vitro culture of immature embryos from K. bipinnata vat. integrifoliola can be enhanced when a small amount of plant growth regulators is added. The addition of BAP has an adverse reaction to the germination and development of immature embryos.

Peanut drying:Effects of various drying methods on drying kinetic models,physicochemical properties,germination characteristics,and microstructure

The current work aims to explore the suitable drying technique for peanut pods which can be used for seeds or edible peanuts.Four drying methods,namely naturally-open sun drying as the control check(CK),hot air drying(HAD),pulsed vacuum drying(PVD),and radio frequency combined hot air drying(RF-HAD),were employed to dry peanut pods,and their effects on the nutritional quality attributes in terms of protein,fat,fatty acid contents,etc.,germination characteristics,microstructure,color,texture,acid value and peroxide value of peanuts were explored.Mathematical models of peanuts drying with four drying methods were also established.According to the statistical parameters including the determination coefficient(R^(2))、root mean square error(RMSE)and chi-square value(v^(2)),theWeibull model was best for predicting the moisture ratio change kinetics of peanuts during its four drying processes.There were significant differences in physicochemical indexes of peanut by different drying methods(p<0.05).Fat and oleic acid contents under RF-HAD were significantly higher than those by the other three drying methods.Compared with the naturally-open sun drying,RF-HAD reduced drying time by 76.70%and the microstructure of RF-HAD peanuts produced larger and more cavities.The RF-HAD kept better comprehensive nutritional quality,but the germination rate was reduced by 27.80%.PVD could maintain good nutritional quality and germination rate among these mechanical drying technologies.However,PVD had a longer drying time of 9.5 h than RF-HAD and HAD,and the microstructure of pulsed vacuum dried peanuts showed dense structure and less cavity.Hot air-dried peanut kernel held the highest protein(28.75%),fatty acids contents(26.11%)and germination rate(88.00%).However,peanut kernel dried by HAD showed poor qualities,such as high acid value,peroxide value and large color changes.These findings indicated RF-HAD was a promising drying technique for edible peanuts regarding the higher drying rate and better-quality preservation,while HAD was suitable for peanut seeds drying as it could well protect the germination rate.

Antifungal Activity of Corydalis Chloroform Extract against Several Kinds of Pathogenic Fungi of Corn and Soybean

In order to better control common diseases of corn and soybean in Sanjiang plain,the in vitro antifungal activity of corydalis chloroform extract against several common fungal diseases of corn and soybeans was tested using mycelial growth rate method. The test result of mycelial growth rate showed that the inhibition rate of corydalis chloroform extract against Cercosporidium sofinum（ Hara） Liu ＆ Guo and Rhizoctonia solani Kuhn were all above 80%,and EC50 values were52. 98- 58. 98 mg /L. The test result of spore germination showed that the inhibition rates against spore germination of all pathogenic fungi were high,in which the inhibition rates against spore germination of C. sofinum and Bipolaris maydis reached 100%. Biological control test showed that the control effects against other diseases were below 60% except that against R. solani reaching 61. 46%.

Autotoxicity of Phthalate Esters in Tobacco Root Exudates:Effects on Seed Germination and Seedling Growth

Autotoxicity is one of the major factors that impede continuous cropping.It is defined as the toxic influence of chemicals released from one plant species on the germination and growth of individuals of the same species.Here, in order to exam the autotoxicity of tobacco root exudates, root exudates were collected from tobacco plants grown both in cultural solution and on natural soil.Using ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry, main autotoxic chemical substances in the root exudates were identified.The autotoxic effects of suspected autotoxins on seed germination(including germination rate,germination potential, germination index, and vigor index) and seedling growth were analyzed.Dibutyl phthalate(or diisobutyl phthalate), dioctyl phthalate, and diisooctyl phthalate were identified in tobacco root exudates.It was observed that high concentrations(greater than 0.5 mmol L^(-1)) of each identified phthalate ester caused significant(P < 0.05) inhibition of tobacco seed germination and seedling growth.It can be concluded that phthalate esters such as dibutyl phthalate, diisobutyl phthalate, and diisooctyl phthalate in tobacco root exudates may play an important role in tobacco autotoxicity.

Seed,cutting and air-layering reproductive inefficiency of noxious woody vine Merremia biosiana and its implications for management strategy

Merremia boisiana(Gagnep)van Ooststr.is a noxious fast growing woody vine and is able to grow overtop other plants,causing the death of plants underneath and forming monospecies stands.To formulate management responses,we assessed its seed and vegetative reproduction efficacy through indoor and field experiments.The number of flowers counted from bagged infructescences in Guangzhou ranged from 25 to 172,with an average of 80.80.Counting the seeds of bagged infructescences had shown that there were only 1.58 hard testa seeds in each infructescence.Seed vitality tests using red ink indicated that only 68.6%of hard testa and filled seeds were viable.The emergence rate of scarified hard testa seeds in the sand bed was 31.96%.Under imitated natural conditions,8%of hard testa seeds could germinate,and 9%still retained their germination potential in one year.Thus,seedlings should be monitored and removed in a timely fashion after any attempt of clearing.Moving soil or transplanting plant from infested patches should be strictly prohibited at least for several years.All considered,an infructescence contributed 0.3 seedlings.The investigation in the field found no seedlings either inside or at the perimeter of the patch,suggesting scant expansion by means of seed dispersal.Therefore,the elimination effort could be focused on a relatively restricted scale of patches.Of 630 cuttings of young shoots,old shoots and old lying shoots with or without growth regulators,there were only four(or 0.63%)established individuals.Air-layering shoots all died in two months.Poor cuttings and airlayering reproduction indicated that regeneration from fragments of removed stems or accidentally dropped ones was quite unlikely,and thus mechanical removal was safe.

Staying alive on an active volcano:80 years population dynamics of Cytisus aeolicus(Fabaceae)from Stromboli(Aeolian Islands,Italy)

Cytisus aeolicus is a narrow endemic species restricted to the Aeolian archipelago(SE Tyrrhenian Sea,Italy)and it is one of the most evolutionarily isolated plants in the Mediterranean flora.Historical and literature data suggest that both metapopulations and isolated individuals of C.aeolicus are gradually shrinking.Field investigations and drone images demonstrate that the C.aeolicus metapopulation from Stromboli experienced a strikingly fast increase during the last decades.As of 2019,more than 7000±3000 mature individuals occur on Stromboli,i.e.14 to 20 times more than those counted during the last census,25 years ago.The diachronic analysis of aerial photos concerning last 80 years and the analysis of the growth rings of some selected plants pointed out that the surface occupied,the demographic structure and the distribution pattern of the subpopulations of Stromboli has been highly fluctuating during last decades.Moreover,data issuing from field observations in permanent plots placed in a transect between two isolated mature individuals showed that,under natural conditions,the germination rate of the seedlings of C.aeolicus can be very high and their establishment rate may exceed 40%.By contrast,seedlings mortality is subject to strong annual fluctuations.Additionally,the pollen morphology of the Strombolian metapopulation of this rare and isolated species is studied here for the first time.Contrary to what is stated in recent literature,the C.aeolicus metapopulation from Stromboli is healthy and very dynamic,albeit frequently damaged by the volcanic activity.Regular and repeated field surveys carried out during 3 years(2017-2019)allowed improving our knowledge on the life cycle of C.aeolicus and a new extinction risk assessment of the species,according to IUCN criteria,is presented.