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[学术文献 ] Photoperiod-sensitive male-sterile mutant in tomato and its potential use in hybrid seed production 进入全文
The Journal of Horticultural Science and Biotechnology
The current practice of manual emasculation of tomato ˉowers for hybrid seed production is labour-intensive and contributes signi?cantly to the high cost of seed. Here we report on a photoperiod-sensitive, single gene male-sterile mutant (7B-1) in tomato which is 100% male sterile in long days (LD, minimum of 12.h daylength) in summer ?eld conditions, but produces many male-fertile ˉowers in short days (SD, 8.h). In LD, 7B-1 ˉowers contain stamens that are pale, short and in the anthers microspore mother cells are differentiated but meiosis does not occur, i.e. microspores and pollen grains are not formed. Unlike the wild type ˉowers, the style and stigma of 7B-1 ˉowers are well exposed and this allows for ready access for pollination without emasculation. In SD, mutant ˉowers possess normal-looking orange-yellow anthers that enclose the stigma and produce normal viable pollen, which when used for pollination of 7B-1 ˉowers yield good fruit- and seed-set. The 7B-1 seed in turn generate a 100% population of male-sterile plants all of which can be used as female parents for hybrid seed production. The female fertility is not affected in 7B-1 ˉowers in both LD and SD conditions. The 7B-1 mutant has been grown in various ?eld locations including, Saskatoon, California, Florida and in Chile, and at all locations it has shown stable male sterility. The 7B-1 mutant is a simple, natural and costeffective system that has a strong potential for use in commercial-scale production of tomato hybrid seed.
[学术文献 ] Calcium distribution in fertile and sterile anthers of thermosensitive male-sterile wheat 进入全文
Grana
Calcium distribution in fertile and sterile anthers of a thermosensitive male-sterile wheat genotype was investigated using an antimonate precipitation method. During fertile anther development, before meiosis of the microspore mother cells, calcium precipitates were apparent in tapetal cells of the anther wall. After meiosis, precipitates were detected in the early microspores and accumulated in the large vacuole of late microspores. After microspore division, following decomposition of the large vacuole, precipitates decreased in the bicellular pollen. The earliest abnormality in calcium precipitate distribution detected during sterile pollen development was the greater accumulation of precipitates in the cytoplasm and nucleus of late microspores. The sterile microspore can divide to form bicellular pollen, but the large vacuole of sterile bicellular pollen did not decompose and greater abundance of precipitates was retained in the large vacuole. Abnormal distribution of calcium precipitates in sterile pollen precedes structural changes, suggesting that abnormal calcium metabolism is associated with pollen abortion.
[学术文献 ] Development of SCAR markers to distinguish male-sterile and normal cytoplasm in bunching onion 进入全文
The Journal of Horticultural Science and Biotechnology
Cytoplasmic male sterility (CMS) is one of the most important systems for the production of F1 hybrid seed. Here, we obtained two sequence-characterised amplified region (SCAR) markers that could distinguish between male-sterile (S) and normal (N) types of cytoplasm in bunching onion (Allium fistulosum L.). A 327-bp S band (designated S327) was amplified in the male sterile line 980238A and a 1,412-bp N band (designated N1412) was amplified in its maintainer line 980238B. Both SCAR markers were verified in five male-sterile lines and their five maintainer lines, in four paternal lines and their self-crossed progenies, and in four cross combinations (one male-sterile line as the female parent and the four male-fertile paternal lines as the male parents). All the results agreed with their corresponding cytoplasmic type (S or N). Our findings suggest that the cytoplasm of A. fistulosum can be identified as male-sterile or normal using these two SCAR markers.These findings are expected to make a significant contribution to breeding F1 hybrid cultivars of bunching onion.
[学术文献 ] Improving salt tolerance threshold in common bean cultivars using melatonin priming: a possible mission 进入全文
Journal of Plant Nutrition
Common bean (Phaseolus vulgaris L.) is mostly cultivated on marginal soils where salinity is a key stress. The focus of the present study was to evaluate the efficiency of melatonin priming and hydro priming on germination, growth parameters, antioxidant defense system and tolerance threshold in seven common bean cultivars grown under different levels of salinity stress. The experiments were conducted as a factorial arrangement based on a completely randomized design with six replicates. The results showed that salinity levels decreased radicle and hypocotyl lengths, seedling vigor index, and salinity tolerance threshold under Petri dish conditions. However, melatonin priming alleviated the inhibitory effects of salinity and enhanced salt tolerance threshold of all the cultivars. The highest tolerance thresholds of Dorsa, Almas, Koosha, and Pak cultivars were obtained under 100?μM melatonin treatment, while in Sayad, Shekoofa, and Derakhshan, 20?μM melatonin caused higher thresholds. Results of the greenhouse experiment showed that melatonin priming increased salt tolerance threshold, but it reduced malondialdehyde content and hydrogen peroxide accumulation. It also induced a higher increase in relative shoot dry weight of the cultivar Dorsa than the other cultivars. The cultivars Dorsa and Shekoofa treated with 100 and 20?μM, respectively, maintained a lower MDA content and Na+ concentration and a higher K+/Na+ ratio in shoot and root, N concentration and salt tolerance threshold than the other cultivars under salinity stress. These results suggest that seed priming with melatonin enhances salinity tolerance by stimulating antioxidant activities, alleviating oxidative damage and enhancing plant dry weight.
[学术文献 ] Selection and validation of reference genes in all-red Amaranth (Amaranthus tricolor L.) seedlings under different culture conditions 进入全文
The Journal of Horticultural Science and Biotechnology
Amaranth is rich in betalain. Both betalain metabolites and plant growth are affected by external factors. However, studies of amaranth seedling growth and betalain metabolism are limited by a lack of appropriate reference genes for qRT-PCR analyses. We selected 13 candidate reference genes from the amaranth transcriptome database and tested their expression stability under various environmental conditions and plant growth regulators. Five methods were used for the analysis: geNorm, NormFinder, BestKeeper, ΔCt, and RefFinder. The most stable reference genes were SAND and RAN1 for light quality, SAND and EIF5a for photoperiod, Actin-7 and TuA for temperature, SAND and Actin-7 for different tissue, SAND and EIF5a for NaCl, SAND and 60S RPL for GA3, 28S rRNA and 18S rRNA for 6-BA, 18S rRNA and 60S RPL for 2,4-D, EIF5a and 28S rRNA for ABA, Actin-11 and SKIP35 for SA, 28S rRNA and Actin-7 for MeJA, SAND and EIF5a for all samples. To further verify the reliability of the reference genes identified in this study, the expression levels of CYP76AD1 were studied in amaranth. This is the first systematic analysis aimed at the selection of reference genes for qRT-PCR in A. tricolor under different culture conditions.
[学术文献 ] Jasmonic acid-induced metabolic responses in bitter melon (Momordica charantia) seedlings under salt stress 进入全文
The Journal of Horticultural Science and Biotechnology
In the present study, effects of foliar application of 150 μM Jasmonic acid (JA), an endogenous plant growth regulator, on alleviation oxidative stress resulted from without (0 mM), low (50 mM), moderate (150 mM), and high (300 mM) NaCl in bitter melon (Momordica charantia) seedlings was investigated. High salt stress significantly decreased growth components including root length, leaf morphological properties, leaf water content, plant biomass and levels of pigments, soluble sugars, starch and proteins, but accumulated higher amounts of proline, free amino acids and the activities of ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and pyrogallol peroxidase (PPX). Exogenous JA treatment alone or combined with salt stress improved growth components with hyperaccumulation of soluble sugars, proteins, amino acids, proline and PPO activity, but was associated with a decrease in the activity of H2O2-decomposing enzymes. These results suggest that exogenous JA treatment can effectively raise salt stress tolerance of bitter melon seedlings through modifying allocation of carbon and nitrogen metabolism to adjust levels of metabolites and directing them to the growth processes.
