AN EVALUATION OF FACTORS AFFECTING SUCCESS OF CONTROLLED CROSSES OF WILD RICE (Zizania palustris L.) IN THE GREENHOUSE

1990 ◽  
Vol 70 (3) ◽  
pp. 677-681 ◽  
Author(s):  
N. J. PAGE ◽  
R. E. STUCKER

The effects of pollen age, stigma age, and time of pollination were evaluated in wild rice (Zizania palustris L.) to develop a pollination procedure that would result in increased seed set in the greenhouse. Pollen age groups, ten stigma ages, and ten pollination times were investigated independently. Pollinations were done in the greenhouse during the months of November through April in 1986–1987 and 1987–1988. Percent seed set was used to assess the treatments. Pollen remained viable for only a short period of time. Maximum percent seed set was attained when pollen from anthers that had been extruded for less than 2 h was used in pollinations. Stigma receptivity remained consistent for 5 d then decreased rapidly. Time of pollination did not have an effect on percent seed set.Key words: Wild rice, pollination biology, pollen viability, stigma receptivity, seed set

Author(s):  
L.R. Tong ◽  
Y. Song ◽  
P. Wang ◽  
J. Wang ◽  
S.G. Ni ◽  
...  

Background: In order to reveal the pollination biological characteristics of Lespedeza davurica, wild L.davurica from eight regions of Shanxi Province was used as test materials to study their floral dynamic, pollen storage and other aspects.Methods: During 2019, the flowering dynamics of wild L. davurica collected from eight regions of Shanxi Province were observed by selecting the better-grown L.davurica. Freshly bloomed flowers were picked, and their pollen was set up for two treatments, dry and undried, for pollen storage experiments. Pollen viability was determined by the TTC (expand for first instance) and MTT (expand for first instance) methods and stigma receptivity was determined by the hydrogen peroxide-benzidine method.Result: The results showed us the following points: the flowers of L. davurica were pale yellow, large and fragrant; it usually opens from the base to the top with distinctly asymmetrical petals; it opens during the day and closes at night; the number of flowers reached its peak between 12:00 and 14:00. After measuring the pollen viability of L. davurica, we found that dry storage at -20°C was the most effective treatment. And with the increase of temperature and decrease of humidity, the pollen viability and stigma receptivity of L. davurica increased continuously and the highest viability value occurs between 12:00 and14:00.


1993 ◽  
Vol 89 (1) ◽  
pp. 165-171 ◽  
Author(s):  
Douglas G. Muench ◽  
O. William Archibold ◽  
Allen G. Good

2019 ◽  
Vol 157 (04) ◽  
pp. 283-299 ◽  
Author(s):  
C. Malumpong ◽  
S. Cheabu ◽  
C. Mongkolsiriwatana ◽  
W. Detpittayanan ◽  
A. Vanavichit

AbstractThe reproductive stage of rice is the most sensitive to heat stress, which can lead to spikelet sterility. Thus, heat-tolerant and heat-susceptible genotypes were used to investigate their differences in terms of phenotypic responses and expression changes of Hsf genes at the pre-flowering stage under heat stress. Results clearly showed that panicles had the highest temperature compared with other plant parts under both natural and heated conditions. However, the temperatures of tolerant and susceptible genotypes were not significantly different. In terms of spikelet fertility, the tolerant lines M9962 and M7988 had high seed set because their anther dehiscence, pollen viability and pollen germination were only slightly affected. In contrast, the susceptible line Sinlek showed severe effects at all steps of fertilization, and the pollen viability of M7766 was slightly affected under heat stress but was more affected in terms of anther dehiscence and pollen germination. Both susceptible lines showed dramatically decreased seed set. In addition, the expression of six HsfA genes in the flag leaves and spikelets at the R2 stage of plants under heat stress showed different responses. Notably, expression of the HsfA2a gene was predominantly upregulated in the flag leaf and spikelets under heat stress in M9962. Therefore, it can be concluded that heat stress has severe effects on the stamen, and that different genotypes have different susceptibilities to heat stress.


2021 ◽  
Vol 13 (13) ◽  
pp. 7211
Author(s):  
Juan Ramón López Soler ◽  
Panayotis Christidis ◽  
José Manuel Vassallo

Teleworking and online shopping became commonplace during the COVID-19 pandemic and can be expected to maintain a strong presence in the foreseeable future. They can lead to significant changes in mobility patterns and transport demand. It is still unclear, however, how extensive their adoption can be, since each individual has different preferences or constraints. The overall impact on transport depends on which segments of the population will modify their behaviour and on what the substitutes to the current patterns will be. The purpose of this work is to identify the user profiles and spatial aspects that affect the adoption of teleworking and online shopping, and to explore the potential impact on transport demand. To that end, data from an EU-wide survey on mobility were analysed using a Machine Learning methodology. The results suggest that while the take up of the new work and consumption patterns is high on average, there are significant differences among countries and across different socio-economic profiles. Teleworking appears to have a high potential mainly in certain services sectors, affecting commuting patterns predominantly in large urban areas. Online shopping activity is more uniform across the population, although differences among countries and age groups may still be relevant. The findings of this work can be useful for the analysis of policies to encourage the uptake of new technologies in transport and mobility. They can be also a good reference point for future studies on the ex-post analysis of the impacts of the pandemic on mobility.


2013 ◽  
Vol 230 (2) ◽  
pp. 284-292 ◽  
Author(s):  
Gangadaran Surendiran ◽  
ChunYan Goh ◽  
Khuong Le ◽  
Zhaohui Zhao ◽  
Fatemeh Askarian ◽  
...  

1956 ◽  
Vol 13 (1) ◽  
pp. 21-39 ◽  
Author(s):  
C. H. Castell ◽  
W. A. MacCallum ◽  
H. E. Power

A study has been made of some of the factors affecting the spoilage rate of fish in the trawlers at sea. It was found that two conditions were major causes of accelerated spoilage: (1) Treatments that resulted in very heavy initial contamination such as storing the fish directly against the slimy wooden pen boards, and (2) Treatments that resulted in a rise in the temperature of the fish. This latter may be a larger increase in temperature for a short period, such as exposure of the fish on the deck during warm summer weather, or a smaller increase over a longer period, such as results from inadequate or inefficient icing.Other types of carelessness and unsanitary conditions did not have any significant effect on the fish until at least 6 or 7 days, as long as they were well iced during the subsequent storage period in the hold.


2021 ◽  
Vol 901 ◽  
pp. 111-116
Author(s):  
Nuttawut Supachawaroj ◽  
Sucharat Limsitthichaikoon

Dry socket disease, a pocket wound caused by the tooth extraction that resulted in severe acute pain which requires a topical analgesic with rapidly pain reduction and suppress the pain until the wound healed. This study aimed to investigate factors affecting gelation temperature and gelation time of lidocaine hydrochloride (LH)-loaded polyelectrolyte complex (PEC) thermosensitivity gel for treating dry socket wound. The first factor was investigated the effects of the ratio of three different types of polymers as chitosan (CS), hyaluronic acid (HA) and poloxamer407 (P407) on the phase transition caused by temperature. The second factor was examined the effects of gel preparation methods. The results showed that increasing concentration of the cationic polymer as CS induced the separation of the solution to gel (sol-to-gel) system due to the charge of CS and the charge of PEC. The ratio of HA:P407 affected the gel forming which high concentration of P407 reduced the gelation temperature while low concentration of HA disturbed the sol-to-gel state causing coagulation. The viscosity, spreadability, and swelling were significantly increased due to the concomitant increased in each polymer, HA and P407. The particle of the formulation observed under microscope was found to be less than 1 µm. Phase inversion from sol-to-gel was found after a min at 23°C. Since gelation temperature of the purposed formula is supposed to form gel below 37°C within a short period of injection. The results of the study indicate the suitable sol-to-gel forming in the appropriate temperature and time which should be used for further investigation in the efficacy and safety.


2021 ◽  
pp. 1-10
Author(s):  
Sourbh Kumar ◽  
Uttam Chandel ◽  
Satish Kumar Guleria

Abstract An investigation to optimize the protocol for application of colchicine for enhancing the doubled haploid production in maize was done. 106 maize genotypes were used as maternal parents, whereas, pollen source involved tropically adopted haploid inducer (TAIL P1 and TAIL hybrid). After the elimination of chromosomes of inducer lines, haploid seeds were obtained from the crosses. Haploid seedlings were treated with three different doses, such as 0.04, 0.06 and 0.08 per cent of colchicines for different durations (8, 12 and 15 hours). The response of various colchicine concentrations applied for different time durations revealed significant differences at P ≤ 0.05 for various parameters viz., per cent plants survivability, stalk colour, the fertility of tassel, silk present/absent, pollen viability, seed set and per cent doubled haploid formation. In maize, colchicine doses of 0.04 per cent for 12 hours and 0.06 per cent for 8 hours, respectively were established as optimum for enhanced doubled haploid production. But among these two, 0.04 per cent for 12 hours was observed to be best dose for doubled haploid production in maize.


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