共查询到20条相似文献，搜索用时 125 毫秒
1.
通过多年大量室内和田间试验与调查,研究了金丝小枣浆烂病病原菌仁果囊孢壳菌Physalospora obtuse对金丝小枣各器官和枣果的侵染、孢子萌发、越冬寄主、子实体形成规律和侵染率与降水量关系.结果表明,病原菌于6月上旬侵染枣吊、果柄,7月上旬开始侵染枣果,8月下旬为侵染高峰期,9月中旬为田间发病高峰期,前期侵染呈潜伏侵染状态.金丝小枣树皮、枣头、枣股及落果、落叶、落吊均为病原菌越冬场所,其中以落果为主.枣园周围杨树、榆树、刺槐、苹果、梨树、桃树亦为病原菌越冬寄主并传播病原菌造成危害.病原菌在越冬病枣果上可形成有性和无性繁殖体;当年病枣果形成分生孢子发生再侵染.8月中旬、下旬雨量大,是造成金丝小枣浆烂病大发生的关键因子. 相似文献
2.
该文研究了枣果采收前后，不同的管理水平导致叶片不同程度提早脱落，对翌年枣树生长发育及枣果产量的影响。结果表明：轻微的落叶（３０％以下）对枣树翌年生长发育及枣果产量影响不大；随着落叶率的增加，枣树翌年新生二次枝长度、枣吊长度、枣叶面积等生长指标及每吊花数、果数、座果率、单果重明显降低，枣果的成熟度加快，枣果产量和质量急剧下降。 相似文献
3.
梨枣枣吊生长与结果习性观察初报 总被引：2，自引：0，他引：2
枣吊是枣树结果的基本单位。我们对嫁接后的第３年幼龄枣树，结合夏季管理，对主枝上新发出的枣头和二次冬季修剪后新发的枣头，按不同的用途和要求进行了摘心，发现摘心后的枣头上及二次枝上长出的枣吊生长较快，长度和粗度均大于已形成枣股上发出的脱落性枣吊，且叶片肥... 相似文献
4.
5.
为了明确越冬期枣树组织中内生真菌的种类和分布情况,并从中筛选出对枣缩果病病原有拮抗作用的内生菌株,从越冬期健康枣树的树皮、枣股、枝条中分离获得内生真菌225株,共鉴定出12个真菌属,其优势属为茎点霉属、链格孢属、毛壳菌属和镰刀菌属。研究结果表明:越冬期健康枣树组织中内生真菌分布普遍,种类丰富;不同品种、不同部位中内生真菌的种类和数量都有差异。室内平板对峙实验结果表明:在225株内生真菌中,有25株内生真菌对枣缩果病病原茎点霉菌1-2有抑制作用,最高抑菌率为85.45%;有14株内生真菌对病原壳梭孢菌1-5有抑制效果,最高抑菌率为76.00%;内生真菌F7和F8对两种病原菌均有抑菌效果,而且均有明显的抑菌带,这说明上述两株菌均可产生抗菌代谢物质。 相似文献
6.
7.
8.
9.
10.
11.
通过对枣树施以不同量配比的碳酸氢铵与过磷酸钙的混合肥料以及结合叶面喷施生长素、赤霉素、生长素与赤霉素混合液的方法,研究了不同施肥量和激素处理对枣树的枣吊长、枣股数、枣吊上的枣花数以及座果数的影响。结果表明:适量的施肥处理可提高枣树的开花座果数,其最佳施肥量为氮肥0.8 kg/株,磷肥0.4 kg/株。不同激素处理对枣树的开花座果数有一定的影响,且影响程度各不一样。 相似文献
12.
１９９２～１９９５年经过对枣步曲排粪规律、食叶量、枣树蓄叶量以及不同失叶水平对枣果产量影响的系统研究,建立了排粪量与平均气温的数量模型：Ｆ∧＝０．５６２９＋０．０１６２Ｔ,枣树蓄叶量估测模型：株蓄叶总面积＝株总枣股数×每股平均枣吊数×每吊平均枣叶数×平均枣叶面积,单位树冠面积下单位时间落粪粒数动态防治指标模型：Ｙ＝（２２６．１９４Ｘ３－３７３．７５４６）Ｘ－２３（０．５６５９＋０．０１６２Ｔ）,经林间验证,准确度在９０％以上。 相似文献
13.
银杏枝叶生长规律与两次采叶试验研究 总被引：5，自引：0，他引：5
本文对栽植后两年的银杏嫁接幼树的枝叶生长规律进行了观察，发现银杏新梢具有春梢和夏梢两种；新梢生长有４种方式；短枝亦分春季展叶生长和夏季展叶生长两种，其中春季展叶生长发生于所有短枝顶芽，而夏季展叶生长一般只发生在顶生短枝顶芽。试验证明，采用全采的方式能有效地刺激所有短枝顶芽全部进行夏季展叶生长；采用两次采收方式能使银杏采叶园的产叶量较传统采收方式（一次采收方式）的产叶量提高１倍。 相似文献
14.
通过对5年生幼龄枣树叶幕形成全部过程的观察,初步掌握了在咸阳市渭北地区的自然条件下,枣树叶幕形成受外界气温和枣股的发育营养状况影响,及不同年龄枣股上抽生冬吊及着叶特点,从而为幼龄枣树早果、丰产栽培技木提供了参考依据。 相似文献
15.
主要研究了麦哈乐（Thifensulfuron methyl）对枣树（Ziziphus jujuba Mill．）新梢生长量、叶片中叶绿素含量、丙二醛含量以及膜相对透性的影响。结果表明：麦哈乐对枣树的正常生长有极严重的影响,试验中均出现了叶片萎蔫、卷曲、失绿、干枯及枝条停止生长的现象。因此,枣园、枣树苗圃地或枣树与农田间（混）作地进行化学除草时,应避免使用麦哈乐。 相似文献
16.
We investigated how shoot gross morphology and leaf properties are determined in Fagus japonica Maxim., a deciduous species with flush-type shoot phenology, in which all leaves are produced in a single flush at the start of each season. We examined relationships between current-year shoot properties and local light environment in a 14-m tall beech tree growing in a deciduous forest. Leaf number (LN), total leaf area (TLA), and total leaf length (SL) of the current-year shoot increased with increasing photosynthetic photon flux density (PPFD). Leaf thickness, dry mass per leaf area and nitrogen content on a leaf area basis increased, whereas the chlorophyll/N ratio decreased with increasing PPFD. To separate the effects of current-year PPFD from those of previous year(s), we artificially shaded a part of the uppermost leaf tier. Reciprocal transfers of beech seedlings between controlled PPFD regimes were also made. Characteristics of shoot gross morphology such as LN, TLA and SL were largely determined by the PPFD of the previous year. The exception was the length of the longest "long shoots" with many leaves, in which elongation appeared to be influenced by both previous-year and current-year PPFD. In contrast, leaf properties were determined by current-year PPFD. The ecological implications of our findings are discussed. 相似文献
17.
研究了施田补对枣树新梢生长量、叶片中叶绿素含量、丙二醛含量以及电导率的影响,结果表明：施田补会抑制枣树新梢生长,减少叶片中叶绿素含量,增加叶片丙二醛的含量和电导率,且浓度越大影响越大,可见在枣树圃地或枣树与农田间（混）作地进行化学除草时,施田补要慎用。 相似文献
18.
We investigated the sapling leaf display in the shade among trees of various leaf lifespans co-occurring under the canopy
of a warm-temperate conifer plantation. We measured leaf-area ratio (aLAR) and morphological traits of saplings of evergreen
broadleaved tree species and a deciduous tree species. Although we found large interspecific and intraspecific differences
in aLAR even among saplings of similar size in the homogeneous light environment, we did not find a consistent trend in aLAR
with leaf lifespan among the species. While deciduous trees annually produced a large leaf area, some evergreen broadleaved
trees retained their leaves across years and had aLAR values as high as those of deciduous trees. Among leaf-level, shoot-level,
and individual-level morphological traits, aLAR was positively correlated with current-year shoots mass per aboveground biomass
in deciduous trees, and with the area of old leaves per aboveground mass in evergreen broadleaved trees. Thus, tree-to-tree
variation in the degrees of annual shoot production and the accumulation of old leaves were responsible for the interspecific
and intraspecific variations in aLAR. 相似文献
19.
Structural variation in current-year shoots of broad-leaved evergreen tree saplings under forest canopies in warm temperate Japan 总被引：1，自引：0，他引：1
Takenaka A 《Tree physiology》1997,17(3):205-210
Stem length and leaf area of current-year shoots were measured in saplings of eight broad-leaved evergreen tree species growing under a forest canopy. Stem length varied over a range of one to two orders of magnitude within each species. In all species, both the number of leaves and the mean stem length between successive leaves were greater in longer shoots. Mean leaf size and stem length were not correlated in six of eight species, and only weakly positively correlated in the other two species. Thus, total leaf area per stem increased with stem length, but not in direct proportion: leaf area per stem length was smaller in shoots with long stems and larger in shoots with short stems. I conclude that the within-species variation in the leaf-stem balance of current-year shoots is related to variation in shoot functional roles, as has been observed for long and short shoots in many deciduous tree species: shoots with long stems are extension oriented and contribute to the framework of the crown, whereas shoots with short stems serve mainly for leaf display. Among species, large differences were found in the leaf area per stem length ratio. In the species with larger leaf area per stem length ratios, leaves had narrower blades or longer petioles, or both, resulting in a reduction of mutual shading among the leaves on the shoot. 相似文献
20.
Narendran Kodandapani Mark A. Cochrane R. Sukumar 《Forest Ecology and Management》2008,256(4):607-617
The Western Ghats in India is one of the 25 global hotspots of biodiversity, and it is the hotspot with the highest human density. This study considers variations in the regional fire regime that are related to vegetation type and past human disturbances in a landscape. Using a combination of remote sensing data and GIS techniques, burnt areas were delineated in three different vegetation types and various metrics of fire size were estimated. Belt transects were enumerated to assess the vegetation characteristics and fire effects in the landscape. Temporal trends suggest increasingly short fire-return intervals in the landscape. In the tropical dry deciduous forest, the mean fire-return interval is 6 years, in the tropical dry thorn forest mean fire-return interval is 10 years, and in the tropical moist deciduous forest mean fire-return interval is 20 years. Tropical dry deciduous forests burned more frequently and had the largest number of fires in any given year as well as the single largest fire (9900 ha). Seventy percent, 56%, and 30% of the tropical moist deciduous forests, tropical dry thorn forests, and tropical dry deciduous forests, respectively have not burned during the 7-year period of study. The model of fire-return interval as a function of distance from park boundary explained 63% of the spatial variation of fire-return interval in the landscape. Forest fires had significant impacts on species diversity and regeneration in the tropical dry deciduous forests. Species diversity declined by 50% and 60% in the moderate and high frequency classes, respectively compared to the low fire frequency class. Sapling density declined by ca. 30% in both moderate and high frequency classes compared to low frequency class. In tropical moist deciduous ecosystems, there were substantial declines in species diversity, tree density, seedling and sapling densities in burned forests compared to the unburned forests. In contrast forest fires in tropical dry thorn forests had a marginal positive effect on ecosystem diversity, structure, and regeneration. 相似文献