叶甲的分类

作者发现叶甲总科内的隐口类只有4个跗节(真4跗型),腹部腹面第一、二两节或多或少愈合;而其他叶甲则都有5个跗节(隐5跗型),腹面第一、二两节一般不愈合。这两点差别,结合其他特征如头型、幼虫型等,说明了隐口类和其他叶甲是两个不同的物群,代表鞘翅目发展的两个不同阶段,应分立为两个不同总科。新总科定名为龟甲总科,下设4个科,即潜甲科、铁甲科、丽甲科和龟甲科。     

EFFECTS OF ELEVATED CARBON DIOXIDE ON ESTIMATION OF LEAF AREA AND LEAF DRY WEIGHT OF SOYBEAN

The objectives of this study were to determine the effects of elevated CO₂ on relationships between leaf area (A) and linear leaf dimensions (length [L] and width [W]) and leaf dry weight (M) in soybeans (Glycine max (L.) Merr. cv. Bragg). Based on dimensional measurements made on trifoliolates 1–6 for plants grown under three CO₂ levels (348, 502 and 645 μl l^−-1), the best predictor for both trifoliolate leaf area and for fully expanded central leaflets of the trifoliolates was an equation of the form A = b_o + b₁L·W; these relationships were unaffected by CO₂, although there was a small effect of leaf position. For expanding central leaflets of the fifth trifoliolate, no CO₂, leaf size (age) or CO₂ × leaf size effect was found. Specific leaf weight (i.e., M/A) was significantly affected by CO₂, increasing with increasing CO₂. Hence, trifoliolate dry weight can be nondestructively estimated from trifoliolate area using the equation M = 0.097 + (6.71 × 10^−-3 + 1.04 × 10^−-6[CO₂])A, where [CO₂] is mean daytime CO₂ concentration of the growth environment.     

淹涝胁迫对水稻叶鞘和叶片中淀粉粒分布的影响

淹涝是世界上当前所面临的最严重自然灾害之一,尤其是近几年来,淹涝给我国的农业生产带来了巨大损失,全国平均每年受涝面积814万hm2,其中成灾面积448万hm2,损失粮食约28亿kg〔1〕。水稻是我国的主要粮食作物,并且分布于淹涝易发生的南方多雨潮湿地区和北方低洼地带,淹涝对水稻产量影响极大,因此,研究淹涝胁迫对水稻的伤害及水稻的耐淹机制越来越受到人们的重视〔2〕。淹涝对植物的伤害并非是因为水分过多而造成的直接伤害,而是由于淹涝造成的次生胁迫,其中最严重的是缺氧。在缺氧条件下,细胞中的碳水化合物代谢途径改变,对植物的生长和发育…     

光强度和光照时间对色叶树叶色变化的影响

1994~1997年我们应用分光光度计法(光谱分析法),对引进的8种色叶树在生长季节叶片自身的光合色素及花色素含量生理指标测定,绘制光合色素含量随时间变化曲线,从而找到了不同季节叶色变化的成因(内因)。由于光合色素含量与温度的关系,光照度的强弱,日照时间的长短等外部因素变化导致色叶树色深浅的变化。     

器官间关系对叶片衰老的影响

叶片衰老是整个植株生理特性的敏感表现,受根系、茎、生殖器官和其他叶片等器官的影响。器官间关系影响叶片衰老可能是通过竞争体内营养、水分等物质、竞争环境因子、源库关系、激素等信息系统调节等机制实现的。从整株水平上加强叶片衰老的生理机制和控制技术研究,将为生产上控制衰老、减少叶片异常衰老造成的产量和品质损失提供有效的技术途径。     

千烟洲针叶林的比叶面积及叶面积指数

根据实测数据计算了湿地松(Pinus elliotii)、马尾松(P. massoniana) 和杉木(Cunninghamia lanceolata)不同年龄、不同类型叶片的生物量和比叶面积,并结合样地调查数据和相对生长方程计算了中国科学院千烟洲试验站20年生湿地松林、马尾松林、杉木林和针叶混交林的叶面积指数。根据拟合结果,选择如下方程计算3个树种的叶生物量:湿地松W=12.074 1D^{2.151 5}、马尾松W=6.972 7D^{2.197 3}和杉木W=5.261 9D^{2.302 7}。湿地松林的叶生物量(0.822 kg·m^-2)最大,其次为针叶混交林(0.679 kg·m^-2),马尾松林和杉木林相差不大(分别为林0.528和0.572 kg·m^-2)。不同树种、不同年龄、不同类型叶片的比叶面积比较发现,新叶的比叶面积大于老叶,三针一束叶的比叶面积略大于两针一束叶,马尾松的平均半比表面积(8.62 m²·kg^-1)大于湿地松(6.04 m²·kg^-1)和杉木(7.91 m²·kg^-1)。胸径与单木叶片半表面积之间的经验方程为:湿地松LA=0.073D^{2.151 5}、马尾松LA=0.060D^{2.197 3}和杉木LA=0.042D^{2.302 7}。据此计算湿地松林的叶面积指数为5.03,马尾松林和杉木林为4.31,针叶混交林为4.77,该结果比利用CI-110植被冠层数字图像仪测得的结果偏大。     

LEAF TRICHOMES OF SOME PARTHENIUM SPECIES

Guayule (Parthenium argentatum), a native shrub of the Chihuahuan desert, contains rubber. Guayule has been crossed with other Parthenium species in an attempt to improve its agronomic characteristics. The resulting hybrids show intermediate morphologies. Each Parthenium species has a characteristic combination of leaf trichomes. In order to recognize the contribution of each parent in future studies of hybrids, characteristics of leaf trichomes of the following Parthenium species were studied: P. tomentosum, P. fruticosum, P. Schottii and P. rollinsianum. All species studied had two or more types of trichomes, and, in some species, trichomes of upper and lower epidermal surfaces were different. The prominent trichomes on upper epidermis of P. tomentosum and P. fruticosum were simple, uniseriate, conical trichomes, which also were observed on both epidermal surfaces of P. Schottii. Extremely long, narrow, simple, whiplike, trichomes formed a dense cover on both surfaces of P. rollinsianum and on the lower surfaces of P. tomentosum and P. fruticosum. Simple, uniseriate, cylindrical trichomes, and biseriate, glandular trichomes were observed in all four species.