A reproducible system for the generation of fertile, transgenic maize plants has been developed. Cells from embryogenic maize suspension cultures were transformed with the bacterial gene bar using microprojectile bombardment. Transformed calli were selected from the suspension cultures using the herbicide bialaphos. Integration of bar and activity of the enzyme phosphinothricin acetyltransferase (PAT) encoded by bar were confirmed in all bialaphos-resistant callus lines. Fertile transformed maize plants (R0) were regenerated, and of 53 progeny (R1) tested, 29 had PAT activity. All PAT-positive progeny analyzed contained bar. Localized application of herbicide to leaves of bar-transformed R0 and R1 plants resulted in no necrosis, confirming functional activity of PAT in the transgenic plants. Cotransformation experiments were performed using a mixture of two plasmids, one encoding PAT and one containing the nonselected gene encoding [beta]-glucuronidase. R0 plants regenerated from co-transformed callus expressed both genes. These results describe and confirm the development of a system for introduction of DNA into maize.

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Transformation of Maize Cells and Regeneration of Fertile Transgenic Plants.

Weeds are known to cause enormous losses due to their interference in agroecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard the phenomenon of allelopathy, which is expressed through the release of chemicals by a plant, has been suggested to be one of the possible alternatives for achieving sustainable weed management. The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop mulch/residues can also give desirable benefits. Not only the terrestrial weeds, even allelopathy can be suitably manipulated for the management of aquatic weeds. The allelochemicals present in the higher plants as well as in the microbes can be directly used for weed management on the pattern of herbicides. Their bioefficacy can be enhanced by structural changes or the synthesis of chemical analogues based on them. Further, in order to enhance the potential of allelopathic crops, several improvements can be made with the use of biotechnology or genomics and proteomics. In this context either the production of allelochemicals can be enhanced or the transgenics with foreign genes encoding for a particular weed-suppressing allelochemical could be produced. In the former, both conventional breeding and molecular genetical techniques are useful. However, with conventional breeding being slow and difficult, more emphasis is laid on the use of modern techniques such as molecular markers and the selection aided by them. Although the progress in this regard is slow, nevertheless some promising results are coming and more are expected in future. This review attempts to discuss all these aspects of allelopathy for the sustainable management of weeds.

Allelopathic Interactions and Allelochemicals: New Possibilities for Sustainable Weed Management

Compounds having the general structure and compositions containing them, for the treatment of acute, inflammatory and neuropathic pain, dental pain, general headache, migraine, cluster headache, mixed-vascular and non-vascular syndromes, tension headache, general inflammation, arthritis, rheumatic diseases, osteoarthritis, inflammatory bowel disorders, inflammatory eye disorders, inflammatory or unstable bladder disorders, psoriasis, skin complaints with inflammatory components, chronic inflammatory conditions, inflammatory pain and associated hyperalgesia and allodynia, neuropathic pain and associated hyperalgesia and allodynia, diabetic neuropathy pain, causalgia, sympathetically maintained pain, deafferentation syndromes, asthma, epithelial tissue damage or dysfunction, herpes simplex, disturbances of visceral motility at respiratory, genitourinary, gastrointestinal or vascular regions, wounds, burns, allergic skin reactions, pruritus, vitiligo, general gastrointestinal disorders, gastric ulceration, duodenal ulcers, diarrhea, gastric lesions induced by necrotising agents, hair growth, vasomotor or allergic rhinitis, bronchial disorders or bladder disorders.

Vanilloid receptor ligands and their use in treatments

The chemical characteristic and distribution of brassinosteroids in plants.

Brassinosteroid: a biotechnological target for enhancing crop yield and stress tolerance

前報の結果から, ビアラホス処理植物体内の遊離アンモニア含量の増加が示唆された. そこで処理植物のアンモニア含量を測定し, さらに殺草効果との関連について検討を行なった. ビアラボス処理による遊離アンモニア含量の増加は, 食用ビエ, メヒシバ, イヌビコおよびムラサキハマスゲで確認され, 処理後24～48時間で無処理の約30倍から100倍に達することがわかった また, アンモニアの蓄積は一過性ではなく持続的であった. 器管の間の比較では, 根よりも茎葉部に, 茎よりも葉により多く認められた. このような顕著なアンモニア蓄積は, 供試した他の除草剤には認められず, ビアラホスに特徴的な作用であった.遊離アンモニア濃度の増加は殺草効果の発現に先立って認められ, その上, 両者に高い相関が認められたので, 殺草効果の主原因はアンモニアの毒性によることが強く示唆された.

Accumulation of ammonia in plants treated with bialaphos.

Structure-activity relationship of brassinosteroids

食用ビエ茎葉部から抽出したグルタミン合成酵素 (GS) に対して, ビアラホスは0.3～3mMの範囲では阻害作用を示さなかったが, インタクトの植物に散布処理した場合, 顕著なGS活性の阻害が認められた. 一方, ビアラホスの代謝物のL-AMPBはそれらの両方でGS活性を阻害した. したがってビアラホスは植物体内で代謝され, L-AMPBになってGSを阻害したと考えられる. ビアラホスを散布処理した食用ビエ茎葉の遊離アミノ酸量を測定したところ, 15種中12種で増加が認められた. 一方, 処理後24～48時間でグルタミンの顕著な減少が認められた. グルタミンの減少が殺草作用の原因であることが考えられたので, ビアラホスをグルタミンとともに散布処理したところ, ビアラホス単独に比べて体内グルタミン量は増加したが, 殺草作用の強さは変化しなかった. したがって, グルタミンの減少は殺草作用の第一義的な要因ではないと考えられる.

Inhibition of glutamine synthetase and quantitative changes of free amino acids in shoots of bialaphostreated japanese Barny and Millet

Since the discovery of brassinolide (1) from rape pollen1} a variety of novel brassinoliderelated plant growth regulators have been found from chestnut insect gall (compounds 52) and 83)), Dolichos lablab (2, 3, 6 and 7)4-6) phaseolus vulgaris (10 and ll),7) Brassica campestris (4, 8 and 9) and Thea sinensis (8 and 9).3) Our recent investigation led to the isolation of a new brassinoliderelated steroid (12) from pollen of Pinus Thubergii Parl. The Pinus pollen (19kg) was processed by the following procedure to afford crystals of 12 (1.7mg, prisms), mp 231~233°C: 1, iso-

Tetsuo Takematsu

Papers

Accumulation of ammonia in plants treated with bialaphos.

Structure-activity relationship of brassinosteroids

Inhibition of glutamine synthetase and quantitative changes of free amino acids in shoots of bialaphostreated japanese Barny and Millet

2-Deoxycastasterone, a New Brassinolide-related Bioactive Steroid from Pinus Pollen

Effects of Brassinosteroids on Growth and Yields of Crops