New Materials for Chinese Brassica (Cruciferae)

The present study deals with external morphology, chromosome number, pollen morphology and seed anatomy of three species of Brassica in China. The results are summarized as follows: 1. Brassica xinjiangensis is described as a new species based on the chromosome number n=9, and 3-4-colpate and reticulate pollen grains. In the transverse section of seed, epidermal cells are triangular, semiterete or irregular, subepidermal cells consist of one series, palisade cells terete and equal in length. Leaves are petiolate or not; stems, sepals, pistils and siliquae are usually covered with retrorse-pilose hairs; rostrum stout, 12 mm long. By the above characters this species differs from others in this genus. 2. Relationship between B. nigra and B. xinjiangensis. In the former all leaves are petiolate, and the lower part of stems and leaves usually bristly; sepals, pistils and siliquae are glabrous; pedicels are erect and appressed to the axis of infructescence; rostrum is gracile, 2.5 mm long. The chromosome number is n=8. Pollen grains are 3-colpate; the exine is cerebroid-reticulate under SEM. In the transverse section of seeds, epidermal cells are undulate, subepidermal cells in 1-2 series, palisade cells terete, short and unequal in length. These characteristics are the same as reported by Koch (1833), Darlington and Wylie (1955), Goldblatt (1981), Vaughan et al. (1971), Lan (1986). 3. Taxonomical position of B. celerifolia. It was treated as B. juncea var. celerifolia by Tsen et Lee (1942). According to the chromosome number n=10, 3-4-colporate pollen grains, it deserves specific rank. This species differs from B. juncea, which has the chromo-some number n=18 and 3-4-colpate pollen grains.     

Cytochemical investigation of genic male-sterility in Chinese cabbage

A genic male sterile Chinese cabbage, Brassica campestris L. ssp. chinensis Makino, was examined using cytological and cytochemical methods to characterize the process of pollen abortion in this plant. Thick sections of both fertile and sterile anthers at different developmental stages were stained using Toluidine Blue O, Periodic Acid-Schiff’s (PAS) reaction and Sudan Black B to detect cytochemical changes that may occur in the distribution of insoluble polysaccharide and lipid storage bodies. Pollen abortion in sterile anthers occurs at an early stage of microspore development. During early microspore development, reductions in the number of starch grains in the connective tissue of fertile anthers coincide with the accumulation of starch grains in cells of the anther wall. In the late microspore stage, a large vacuole forms in the microspore, and tapetal cells synthesize and accumulate lipid droplets. The cellular organization of tapetal cells in sterile anthers appears similar to that in fertile anthers, except for the absence of lipid droplets in cells of sterile anthers and diffusely labeled tapetal polysaccharides, suggesting defects in nutrient storage. Supported by National Natural Science Foundation of CHINA (30170060)     

子房注射法与农杆菌介导法转化甘蓝型油菜的比较研究

以甘蓝型油菜湘油１３号为试验材料,运用根癌农杆菌介导法和子房注射法成功地将Ｂｔ杀虫蛋白基因导入油菜,在特定的条件下,以子叶柄作为转化受体进行农杆菌介导转化,其转化效率受侵染时间和共培养时间的影响,最佳侵染时间为３－５ｍｉｎ,最佳共培养时间为６０－７２ｈ;子房注射法的最佳注射时间为授粉后第２０－３０ｈ,最适注射部位为子房中部,ＤＮＡ注射量为０．５－１．５μｇ,在最佳转化条件下它们分别获得抗卡那霉素植     

The distribution of caprylate, caprate and laurate in lipids from developing and mature seeds of transgenic Brassica napus L.

The composition and positional distribution of lipids in developing and mature transgenic Brassica napus seeds accumulating up to 7 mol% of caprylate (8:0), 29 mol% caprate (10:0) or 63 mol% of laurate (12:0) were examined. The accumulation of 8:0 and 10:0 resulted from over-expression of the medium-chain-specific thioesterase (Ch FatB2) alone or together with the respective chain-length-specific condensing enzyme (Ch KASIV). Seeds containing high levels of 12:0 were obtained from plants expressing bay thioesterase (BTE) alone or crossed with a line over-expressing the coconut lysophosphatidic acid acyltransferase (LPAAT), an enzyme responsible for the increase in acylation of 12:0 at the sn-2 position. In all instances, 10:0 and 12:0 fatty acids were present in substantial amounts in phosphatidylcholine during seed development with a drastic decrease of 80–90% in mature seeds. At all stages of seed development however, 8:0 was barely detectable in this membrane lipid. Altogether, these results indicate that these transgenic seeds exclude and/or remove the medium-chain fatty acids from their membrane and that this mechanism(s) is more effective with the shorter-chain fatty acids. Furthermore, seeds of 8:0- and 10:0-producing lines had only negligible levels of these fatty acids present in the sn-2 position of the triacylglycerols. In contrast, all 12:0-producing seeds had a substantial amount of this fatty acid in the sn-2 position of the triacylglycerols, suggesting that the endogenous LPAAT is able to acylate 12:0 if no other acyl-CoA species are available. Received: 11 February 2000 / Accepted: 2 May 2000     

菜心组织培养技术初探

为建立菜心(Brassica campestris ssp.chinensis var.utilis)的快繁技术体系,以花药和子叶-子叶柄为外植体进行组织培养研究。结果表明,花药培养以选取未开放的花蕾为宜,且花柱略高于花瓣,此时小孢子多数处于单核靠边期。菜心花粉的萌发率不高,且秋冬季的花粉比夏季的萌发率高。菜心花药愈伤组织诱导培养基为:MS+1.0 mg L–1 KT+1.0 mg L–1 2,4-D+3%糖+6 g L–1琼脂+8%椰乳,不定芽诱导培养基为:MS+2.0 mg L–1 6-BA+0.5 mg L–1 NAA+1.0 g L–1活性炭+2%糖+6 g L–1琼脂或MS+2.0 mg L–1 ZT+0.5 mg L–1 IAA+0.5 g L–1 AgNO3+1.0 g L–1活性炭+2%糖+6 g L–1琼脂。花药培养的不定芽诱导率为36.7%,不定芽培养出现褐化现象,不能形成再生植株;而以子叶-子叶柄为外植体培养获得的植株再生率可达80%。     

Physiological effects of Na2SO4 and NaCl on callus cultures of Brassica campestris (Chinese cabbage)

Hypocotyl-derived callus cultures of Brassica campestris L. ssp. pekinensis cv. Kim-jung (Chinese cabbage) were grown on Murashige and Skoog medium containing no additional salt, NaCl or Na₂SO₄. Na₂SO₄ was more than twice as inhibitory in comparison to the same concentration of NaCl when growth and fresh:dry weight ratios of established callus were measured. Levels of protein, starch, sucrose and α-amino nitrogen were not significantly altered in salt-grown callus. Concentrations of reducing sugars and chlorophyll were 2–3 times greater in callus grown on either salt. Proline concentration increased 15–20 fold on the highest levels of salt. Final concentrations (reached in 20–24 days) were closely correlated to the initial Na⁺ concentration of the medium, regardless of salt type. The osmotic potential in callus transferred to NaCl or Na₂SO₄ reached a maximum negative value after 16 days. For both salts, subsequent increases were correlated to increases in fresh:dry weight and growth. On both salts, turgor remained relatively constant (0. 6–0.75 MPa). Changes in Na⁺, K⁺, Mg²⁺ and Ca²⁺ content were correlated to initial Na⁺ concentration in the medium, not salt type. Accumulation of Na⁺ was accompanied by loss of K⁺ and Mg²⁺. Six to seven times less sulfate was measured in callus grown on Na₂SO₄ than chloride in callus grown on similar concentrations of NaCl.     

The effect of wild radish floral morphology on pollination efficiency by four taxa of pollinators

The effects of floral morphology on rates of pollen removal and deposition by different pollinators in generalist plant species are not well known. We studied pollination dynamics in wild radish, Raphanus raphanistrum, a plant visited by four groups of pollinators: honey bees, small native bees, butterflies, and syrphyd flies. The effects of anther position and other factors on pollen removal during single visits by all four pollinator taxa were measured. Flowers with high anther exsertion (i.e., anthers placed higher above the opening of the corolla tube) tended to have the highest numbers of pollen grains removed, but this effect was strongest for honey bees and butterflies. For all pollinator taxa, pollen removal increased with the number of pollen grains available on a flower and whowed a positive, decelerating relationship with the duration of the visit. The effects of stigma position and other factors on pollen deposition during single visits by honey bees and butterflies were also studied. The nectar-feeding butterflies had a higher pollination efficiency (percentage of pollen grains removed from anthers that were subsequently deposited on a stigma) than the nectar- and pollen-feeding honey bees. Flowers with intermediate stigma exsertion had the highest numbers of pollen grains deposited on their stigmas by butterflies, but stigma exsertion had no effect on deposition by honey bees. For both butterflies and honey bees, pollen deposition on the recipient flower increased with the amount of pollen removed from the donor flower, and there was a positive, decelerating relationship between deposition and time spent at the flower; these results are analogous to those for pollen removal. The effects of anther and stigma exsertion on pollen removal and denosition did not fit predictions based on patterns of floral correlations, but results for morphology, pollen availability, time spent per visit, and pollinator efficiency are in broad agreement with previous studies, suggesting the possible emergence of some general rules of pollen transfer.     

豇豆胰蛋白酶抑制剂基因转化芥菜及抗虫鉴定

用农杆菌介导将豇豆胰蛋白酶抑制剂 (CpTI)基因导入芥菜 ,获得了Kan抗性植株 .经PCR扩增、PCR Southern印迹和Northern印迹分析 ,转化再生植株大部分呈阳性 ,而非转化的再生植株均为阴性 ,证明CpTI基因已存在于芥菜基因组中 .在室内进行了喂虫试验 ,结果表明转基因芥菜抗虫性明显高于对照 ,转基因植株之间存在抗虫性差异