Foliar and shoot allometry of pollarded black locust, Robinia pseudoacacia L.

Browse of multipurpose tree species such as black locust could be used to broaden grazing options, but the temporal distribution of foliage has not been adequately studied. Our objective was to determine effects of harvest date, P fertilization (0 and 600 kg ha⁻¹ yr⁻¹), and pollard height (shoots clipped at 5-, 50-, and 100-cm above ground) on foliar and shoot allometry of black locust. The experiment was conducted on a naturally regenerated 2-yr-old black locust stand (15,000 trees ha⁻¹). Basal shoot diameter and foliar mass were measured monthly in June to October 2002 and 2003. Foliar and shoot dry mass (Y) was estimated from basal shoot diameter (D) by the function Y = aD ^b , with regression explaining ≥95% of variance. Allometry of foliar mass was affected by harvest date, increasing at a greater rate with D in September than in June or July, but not by P fertilization or pollard height. Foliar mass was predicted best by month-specific equations for the June to October growth interval. Allometry of shoot dry mass was unaffected by harvest date, P fertilization, or pollard height. These equations could be used as a first approximation of foliar and shoot mass for pollarded black locust.     

枣树绿枝扦插试验研究

本试验选用当年生半木质化枣头发育枝作扦插材料，用不同激素、不同浓度进行处理，以河沙做扦插基质；用塑料小拱棚和人工洒水调控温湿度；用竹帘搭棚遮荫简单行的方法，使枣树绿枝扦插当年成活率达８５％以上。冬季采用覆麦草越冬。     

福建酸竹鲜笋采后防腐保鲜剂研制

本次实验结果显示福建酸竹笋发霉的致病菌为青霉、曲霉和枝孢霉。通过抑菌实验可得出最佳的复合防腐配方为B13B233%食盐。在确定保鲜配方的生笋实验中,得出福建酸竹生笋保鲜液的最佳配方为复配防腐液(A 0.08? 0.05? 3%食盐县pH=4.5) 0.03? 0.03?,该配方经省检疫局检测LD50>20m l.kg-1(比重1.043),几乎无毒,属于对人体安全保鲜液。用此复配防腐液处理福建酸竹笋在贮藏27天时还能保持可食性,保鲜效果明显,具有很大的推广前景。     

Phenology Differs among Norway Spruce Populations in Relation to Local Variation in Altitude of Maternal Stands in the Beskidy Mountains

An investigation of phenological and growth traits was conducted in a lowland plantation, comprised of 23 Norway spruce (Picea abies (L.) Karst.) seed stands from the Istebna region in the Beskidy Mountains of Poland. Significant differences were found among population in growth initiation, growth termination and the length of shoot elongation period. The two latter traits were highly correlated and were attributed to the altitude of the maternal stand. The tested populations were grouped based on phenology. Progeny of lower-alttitude stands ceased growth later, had a longer duration of shoot growth and greater current leader length compared to progeny of higher-altitude stands. Individual populations, however, did not differ in current-year growth and total tree height, implying higher within-population variation in growth traits than in phenology. The similar growth capacity of all tested populations suggests considerable gene flow between maternal stands, although differences in phenology imply the adaptation of progenies to the altitudinal environment of seed origin. These results suggest that within tested populations, selection is possible based on phenology alone, without considerable reduction of early height growth; final decisions, however, should be based on the environmental conditions of the planting site.     

油松嫩枝扦插育苗试验

用油松嫩枝作插穗，在粗河沙中扦插育苗，插后先形成愈合组织，后从愈合组织处生根，皮部不生根．以浓度１０００μｇ／ｇ萘乙酸处理生根率最高，为５７．７％，移栽成活率为９４．９％。     

东革阿里组织培养初报

通过对东革阿里不同生长时期的枝条进行离体培养,结果表明:老化的枝条较难进行消毒,当年萌发的新枝条消毒相对易些;能诱导出东革阿里愈伤组织的培养基是MS+6-BA0.5mg/L+NAA0.01mg/L+3%蔗糖。     

Responses of Root Growth to Moderate Soil Water Deficit in Wheat Seedlings

Abstract

In the field, plants show better root growth in drying soil than in wet soil. However, the root growth enhancement has not been demonstrated clearly in the laboratory. In this study, the root growth response of wheat seedlings to moderate soil water deficits was characterized quantitatively in an environment-controlled chamber. Germinated seeds of wheat were grown for 15 days in the soil with a water potential ranging from field capacity (FC) to approximately –0.08 MPa. Theleaf area decreased with reduction in soil water potential. By contrast, the root surface area increased upon reduction ofthe soil water potential to –0.04 MPa while it decreased significantly in soil with a water potential of –0.08 MPa. The increase in surface area was obvious in the roots with a diameter of 0.2 to 0.4 mm and larger than 0.7 mm. Root weight increased with the reduction of soil water potential to –0.04 MPa. While specific root length decreased significantly with the reduction of water potential to –0.06 MPa, the specific root surface area did not. Assimilatestransported from shoot might be used in roots to increae the surface area mainly by increasing the diameter rather than the length in response to a moderate soil water deficit in wheat seedlings. This might result from the drought tolerance mechanism of osmotic adjustment in roots.     

Tree Mortality,Needle Biomass Recovery and Growth Losses in Scots Pine Following Defoliation by Diprion pini (L.) and Subsequent Attack by Tomicus piniperda (L.)

Tree mortality and growth losses following insect defoliation are poorly documented in Scandinavia. In 1990-1991, Diprion pini (L.) caused extensive defoliation to Scots pine in Lauhanvuori national park and surrounding areas in south-western Finland. Most trees lost all their foliage in 1990. In 1991, the outbreak area was sprayed with diflubenzuron (Dimilin®), except in the national park, where trees were severely defoliated again. No further defoliation occurred in 1992. In spring 1993, sprayed trees had ca 30% foliage, whereas unsprayed trees on average carried less than 10% of full foliage. The latter trees were susceptible to attack by Tomicus piniperda (L.), whereas the former largely escaped beetle attack. Beetle attacks peaked in 1993, and depletion of suitable host trees probably terminated the beetle outbreak in the area. Two years of severe defoliation resulted in substantial tree mortality and growth losses. In spring 1997, these unsprayed stands had suffered a ca. 50% loss in basal area which was mainly because of mortality, and about half of the dead trees had been attacked by T. piniperda. Surviving trees had ca 50% of full foliage, and radial growth had still not recovered. Basal area growth was reduced by 40-70%, depending on the amount of foliage left after the second year of defoliation. In contrast, tree mortality and beetle attack in the sprayed stands were negligible, and these trees had recovered full foliage and radial growth by spring 1997. Thus, one year of total defoliation resulted in an estimated loss in basal area growth of approximately 30% during ca. 5 yrs. In conclusion, the spraying operation was economically justified, as it prevented substantial tree mortality and reduced growth losses.     

控制灌水对梨幼树枝条生长和成花的影响

以3年生梨幼树为试材,研究了4种不同灌水处理对梨幼树枝条生长和花芽形成的影响。结果表明,在冬季一次灌水(250m~3/亩)的基础上,减少土壤供水可有效地控制新梢长度和粗度,缓和树势,增加花芽数量。减少土壤供水可使幼树总生长量轻微下降,主干生长减弱,树冠长梢比例下降,中、短梢比例增加,单位主干横截面积上的花芽数明显增加。生长季节控制灌水,可节约灌水量、扩大灌溉面积、并能促使梨幼树早期结果。