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1.
东北草原羊草种群结实特性与气候年变化的关系   总被引:9,自引:0,他引:9  
对3个固定样地的羊草(Leymus chinensis(Trin.)Tzvel.)种群连续12 ̄16年的调查和测定及其与不同生长发育阶段气候因子的相关分析,表明羊草种群结实数量和籽实重量均与形成这些性状的生育期内,及其以前各生育期不同阶段的光照时间、积温、降水量有着一定程度的相关关系。从分蘖株的营养生长到生殖生长,包括开花、授粉、受精、胚珠发育为种子形成的整个过程中,较低的温度和生长季前期较多的光  相似文献   

2.
东北草原羊草种群种子生产与气候波动的关系   总被引:27,自引:0,他引:27  
羊草(Leymus chinensis(Trin.)Tzvel.)是一种优良的多年生禾本科牧草。东北草原羊草种群种子生产有明显的丰欠年现象。通过对3个固定样地连续12-16年的调查和测定及其与不同生长发育阶段光照时间、积温、降水量的相关分析,发现气候变化是引起羊草种群种子生产丰欠年的重要因素之一。秋季低温、多雨,翌年将是种子生产的丰年,而高温、干旱则是欠年。相反,春季高温、干旱是种子生产的丰年,而低温、多雨则是欠年。气候因子对羊草种群种子生产有明显滞后的生态效应,其影响的生态时间差可长达10-12个月之久。用前一年8-10月不同阶段的降水可预报翌年羊草种群的抽穗数量和籽实产量,但由单项降水因子引起的诸数量变化为44%-61%。  相似文献   

3.
恢复措施对退化草地羊草种群有性生殖数量特征的影响   总被引:10,自引:2,他引:8  
在封育和翻耙处理的退化羊草草地上,对羊草种群有性生殖的数量特征进行了比较研究.结果表明,翻耙样地羊草种群密度下降显著,生殖蘖密度变化不显著,生殖蘖穗长、节间长、生殖生长比率、穗节数、小穗数、小花数、饱满籽实数和结实率都有显著增长,籽实产量、净籽实重和千粒重分别是封育样地的2.68、3.49和1.3倍.在翻耙样地中,羊草种群发育有复小穗的生殖蘖比封育样地多16%,生殖蘖上复小穗的数量也显著增加,生殖蘖以相对少的小穗,生产了较多的小花和更多的籽实来提高种群的籽实产量.两个样地中羊草种群的生物量生殖分配在种群对生殖蘖RA1、生殖蘖对穗序RA4、穗序对籽实RA6 3个层次上无显著差异,而种群对穗序RA2、生殖蘖对籽实RA5的生殖分配差异显著,种群对籽实RA3的生殖分配差异极显著.  相似文献   

4.
以河南省大面积种植的弱春性品种"郑麦9023"及半冬性品种"周麦18"为材料,开展了玻璃温室和田间栽培条件下小麦幼穗分化进程的比较研究。结果表明,在小麦全生育期,玻璃温室内平均温度高于田间环境,小麦幼穗分化所需时间极显著低于田间环境(P < 0.01)。温度和0 ℃以上积温升高,小麦幼穗分化进程加快。与田间种植小麦相比,玻璃温室内小麦幼穗分化缩短的时期主要集中在分化前期(出苗-伸长期、单棱期、二棱期)。玻璃温室内小麦幼穗分化持续时间和总积温均随播期推迟而降低,幼穗分化各阶段出现时间亦随播期的推迟而后延。小麦幼穗分化进程存在品种间差异,其中"郑麦9023"幼穗分化持续时间小于"周麦18",各阶段出现的时间亦早于"周麦18"。温度对幼穗分化各时期的影响存在品种间差异。温度升高对"郑麦9023"幼穗分化中期(二棱期、护颖分化期、小花分化期)影响较大,对"周麦18"幼穗分化前期和后期(单棱期、二棱期、药隔分化期)影响较大。积温对"郑麦9023"护颖分化期和"周麦18"药隔分化期、二棱期影响较大。  相似文献   

5.
羊草种群地上部生物量形成规律的探讨   总被引:24,自引:1,他引:23       下载免费PDF全文
 本文从种群生态的水平研究了中国东北草原的主要优势植物——羊草种群地上部生物量的若干形成规律。羊草种群每年从4月初返青,其地上部生物量的相对增长速率在抽穗前(5月中旬一下旬)最快,达0.1142克/克/天,绝对增长速率在盛花期(6月中旬一下旬)最快,达7.46克/米2/天。前者决定于羊草的自身发育节律,后者受生长季内的气温和降水的约制。羊草种群总生物量的变化曲线呈单峰形式,峰值出现在8月中旬,达305克/米2。继后,生物量逐渐下降至10月中旬地上部全部枯死。据观测,影响羊草种群地上部总生物量的限制因素是:生长季前期(4一7月)的降水量。羊草种群地上部总生物量峰值的高低,依赖同化器官生物量的增长,总生物量与同化器官生物量的增长呈强正相关(r=0.9472**)。  相似文献   

6.
越冬前增温对小麦生长发育和产量的影响   总被引:6,自引:0,他引:6  
为了揭示越冬前积温增加对冬小麦生长发育进程和产量的影响,于2010—2012年在设施内进行人为控制增温模拟试验.以试验期室外环境实测温度值为对照,设置越冬前增温40、50、60 d,研究越冬前不同积温(≥0℃)对小麦物候期、幼穗发育进程、开花期和成熟期叶片光合生理特性及产量构成要素的影响.结果表明:设施内越冬前增加积温在越冬前对幼穗发育进程有一定影响,对拔节期幼穗发育进程和育性影响明显,孕穗后随着发育进程的加快影响减小,成熟期大部分处理间的生物学性状差异不显著.越冬前积温增加不超过25℃对幼穗影响很小;积温增加大于60℃幼穗发育进程明显加快,积温越高变化越明显.冬前积温增加到一定幅度将导致冬小麦物候期提前,积温增加超过60℃,拔节期叶龄提高0.8以上,抽穗期和成熟期分别提前1 d左右.物候期的提前和幼穗发育进程的加快使小麦整个发育期缩短,容易遭受春季低温危害,造成小花败育甚至小穗冻死;冬前积温过高还导致后期旗叶光合能力下降,灌浆期缩短,并造成减产.  相似文献   

7.
小麦形成大穗的生态学基础   总被引:11,自引:5,他引:6  
研究了不同光、温条件下3个小麦品种的生育特征、幼穗分化、幼穗生长和穗部性状,探讨了促进穗大粒多、提高小麦单产的可行途径.结果表明,因播种期的不同而导致的小麦生长期间光、温条件的不同,使之各生育期出现的时间及其持续的天数有了较大的差异.小麦幼穗分化的历期天数多与平均气温和平均日照长度呈显著或极显著负相关.不同的积温是幼穗生长量和每穗总小穗数产生差异的重要原因.在条件适宜的麦区,可望通过引种适宜品种并适当提早播种期,以促进德大粒多、实现单产的明显提高.  相似文献   

8.
秦之旷  刘娜  周霞  李志辉  曹福亮  李何 《广西植物》2023,43(9):1622-1635
赤皮青冈(Quercus gilva)是我国中亚热带地区极具经济价值的珍贵用材树种。为揭示其表型多样性与变异规律以及影响表型变异的关键地理气候因子,该研究以14个赤皮青冈天然种群115个单株为材料,对其15个树体和叶片性状进行测量,并采用巢式方差分析、表型分化系数分析、多样性指数分析、相关性分析、主成分分析以及聚类分析等方法,探究赤皮青冈的表型变异规律及其与地理气候因子的相关性。结果表明:(1)赤皮青冈表型多样性水平较高,15个表型性状的变异系数和Shannon-Wiener指数平均值分别为35.070%和1.998,14个种群的变异系数在14.94%(洞口)~35.56%(龙山)之间、Shannon-Wiener指数在1.127(松阳)~1.980(常宁)之间。(2)15个表型性状在种群间和种群内均存在极显著差异(P<0.01),种群平均表型分化系数为41.491%,表型变异主要来源于种群内。(3)相关性分析发现,赤皮青冈部分性状间存在显著或极显著相关性,表型性状与地理因子间相关性不明显,降水是影响赤皮青冈表型性状的主要气候因子。(4)主成分分析发现,基于11个表型可提炼出4个...  相似文献   

9.
为研究短日照对北方春夏播燕麦穗发育的影响,以5个光周期敏感品种和1个光周期不敏感品系分析日照长度对燕麦穗分化发育的影响,并比较燕麦光周期敏感品种和不敏感品系在海南自然短日照条件下的生长发育情况。结果表明,遮光条件下,当日照长度由正常光照15 h减少至11 h时,光周期敏感品种的燕麦幼穗分化进程不能正常进行,形态上穗部发育退化严重,不能完成生长发育;而光周期不敏感品系能正常进行穗分化,完成整个生长发育。在海南自然短日照条件的试验表明,北方春夏播燕麦在自然短日照条件下,光周期不敏感品系能抽穗结实,完成整个生长发育过程,光周期敏感品种在生育期内不能抽穗,只有营养生长没有生殖生长。裸燕麦不同品种之间及皮裸燕麦之间在正常穗分化情况下,扫描电镜形态无明显差异。对光周期敏感的燕麦品种在每日11 h的短日照条件下,不能完成穗发育分化进程,只进行营养生长,即使是短生育期的燕麦也不能完成抽穗开花结实,导致绝产。燕麦品种生育期与光周期敏感性不存在相关性。  相似文献   

10.
《植物生态学报》2013,37(11):998
以云南省思茅松(Pinus kesiya var. langbianensis)天然分布区的11个种群的16个种实性状为研究对象, 采用巢式方差分析、变异系数、相关分析和非加权配对算术平均法(UPGMA)等多种分析方法, 探讨思茅松种群间和种群内的表型变异。结果表明: 思茅松种实表型性状在种群间和种群内均存在着较丰富的差异, 种群内的变异(54.76%)大于种群间的变异(10.44%), 种群间平均分化系数为11.95%, 分化程度相对较小。球果总种子数的平均变异系数最高(35.51%), 其次是球果质量(35.1%), 种子大小的平均变异系数最小(8.86%), 成为最稳定的种实性状; 景谷县的表型多样性最丰富, 景洪市则最小。球果和种子大部分表型性状之间存在显著或极显著相关, 其中球果长和球果质量越大, 种鳞长、种子长、种翅长、千粒重、球果总种鳞数和球果总种子数就越大。生态因子中, 年平均气温对表型性状影响最大, 其次是1月平均气温和>5 ℃积温。利用种群间聚类分析可以把思茅松的11个种群分为2类4个亚类, 表型性状依据地理距离进行聚类, 聚类结果与年降水量和>5 ℃积温相关性显著。  相似文献   

11.
Application of the growth retardant paclobutrazol (PP333), at 2 kg a.i. ha-1 at spikelet initiation to plots of perennial ryegrass cv. S.24 in 1981 and 1982 significantly increased the number of seeds per spikelet present at final harvest by reducing the number of seeds aborted during seed development. Distribution of florets and seeds per spikelet was altered by PP333, as both basal and penultimate spikelets contained more florets and seeds than did those of untreated plants. Seed weight and germination were increased in florets of penultimate spikelets, although PP333 application delayed maturity by 3–5 days. In untreated plants, assimilate recovery was significantly lower from the terminal section of the ear, whereas in PP333 treated plants, no differences were found between basal, intermediate or terminal sections of the ear. PP333 increased assimilate demand at all sections of the ear when the ear and leaves were fed. The implications of this are discussed.  相似文献   

12.
This paper describes the effects of sterilizing certain floretson the development of others within the ears of wheat, cultivarMaris Ranger. Sterilization of all the florets in spikelets2, 4, 6, and 8 (numbered from the base of the ear upwards) ledto more grain setting and greater grain growth in the untreatedspikelets. These compensatory increases were insufficient toprevent a depression in the yield of grain per ear. Sterilizationof more than one of the basal florets of spikelet 8 led to amore frequent setting of the grain in the distal florets onthat spikelet and to the centrally positioned grain becomingheavier. The physiological basis for the inhibitory influences of theolder and developing grain on the unfertilized florets and youngergrain is discussed.  相似文献   

13.
The maize sex determination pathway results in the arrest of stamen in ear spikelets and the abortion of pistils in both the tassel spikelets and in the secondary florets of ear spikelets. Arrested stamen cells showed no signs of DNA fragmentation, an absence of CYCLIN B expression, and an accumulation of the negative cell cycle regulator WEE1 RNA.  相似文献   

14.
Wheat, variety Sonalika, was grown at different densities inboth field and pots during the winter seasons 1983–84and 1984–85. Grain yield pattern of the spikelets of themain shoot inflorescence was similar in both the field and pots,the spikelets in the middle part of the ear contributed mostand yield per spikelet decreased progressively towards the apexand the base. Increased population density decreased yield ofgrain, primarily by decreasing spikelet number and the fertilityof florets. High population density accelerated growth of thespike for some time during the pre-anthesis period and the solublecarbohydrate concentration was also higher under these conditions.During both anthesis and post-anthesis, the soluble carbohydrateconcentration and the growth of the spike declined much fasterin the high-density population. High density also decreasedthe floret fertility and growth in dry weight in all the spikelets,but it was more severe on the basal spikelets, resulting incomplete sterility of the florets at these nodes. The solublecarbohydrate concentration of these slow-growing, sterile, basalspikelets was found to be higher in comparison to that of fertilespikelets in the middle and top positions within the ear. Soluble carbohydrates, spike, spikelet, fertility, grain number  相似文献   

15.
Grain number in the wheat cultivar Banks was reduced by up to11 % with a rise in temperature from 21/16 °C to 30/25 °Cover a 10-d period immediately following first anthesis in general,the upper ‘d’ and ‘c’ florets were moreaffected by high temperature than the basal ‘a’and ‘b’ florets within a spikelet and florets fromthe upper spikelets were more sensitive than those lower onthe ear Grain weight and grain length at maturity were most affectedby a 10 d period of high temperature commencing 7–10 dafter anthesis However, if dry-matter accumulation between thestart of a treatment and grain maturity was used as a base forcomparison, the response was more uniform throughout development,with a peak in sensitivity 25 d after anthesis Although grainposition within an ear did not have a large effect on the responseto temperature, grains from the basal spikelets were more sensitivethan those from the apex, and the upper floret grains of a spikeletwere more sensitive to high temperature than those at the base There is a need to obtain, for a range of cultivars, more comprehensivedata on the effect of the timing and degree of temperature stressfollowing anthesis, for use in interpreting the response torising temperatures late in the development of the crop in thefield Triticum aestivum L, wheat, temperature, grain development  相似文献   

16.
Abstract: Apigenin, a pharmacologically important flavonoid of the chamomile plant, was analyzed at two ploidy levels during a three-year period. This flavonoid accumulates in the ligulate florets of the anthodium. Higher percentages of apigenin were found in the ligulate florets of a diploid cultivar, in comparison with tetraploid plants. However, when the total apigenin (mg of compound) in the anthodium was evaluated, tetraploid individuals accumulated significantly more flavonoid. Moreover, in contrast to morphological quantitative characteristics of the anthodium, which varied significantly in different years, apigenin percentage in the ligulate florets was constant and not influenced by environmental conditions. Apigenin content was also found to change during inflorescence ontogeny. It represents the highest percentage of dry mass in young developing florets and anthodia of both cultivars. The total apigenin content of the anthodium, however, increases during flowering, although at later stages apigenin forms only a minor part of ligulate floret and anthodium dry mass.  相似文献   

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