Growth April Research Articles

Modeling hydrological consequences of 21st-Century climate and land use/land cover changes in a mid-high latitude watershed

The Naoli River Basin (NRB), a pivotal agricultural production area in China, is poised to undergo substantial impacts on water resources due to projected climate and land use/cover (LULC) changes. Despite its significance in the context of China's expanding farmland construction in the NRB, there exists limited research on the potential repercussions of future shifts in runoff, soil water content (SWC), and evapotranspiration (ET) on crop productivity and water availability (both in terms of quantity and timing). This study employs future LULC maps and an ensemble of ten CMIP6 Global Climate Models (GCMs) across three scenarios to drive the well-calibrated distributed hydrological model, ESSI-3. The objective of present study is aimed on projecting hydrological consequences under climate and land use/land cover changes in near-term (2026–2050), middle-term (2051–2075), and far-term (2076–2100) future in comparison to the baseline period of 1990–2014. Results consistently indicate an increase trend in annual average ET, runoff, and SWC in the NRB across all three future periods under the three SSP scenarios. LULC changes emerge as the primary driver influencing regional hydrological processes in the near future. Notably, under high-emission scenarios, monthly runoff and SWC are projected to significantly increase in March but decrease in April during the middle and far future periods compared to the baseline. This shift is attributed to the anticipated warming of winter and spring, leading to a transition in peak snowmelt from April to March. Concurrently, the expansion of cropland intensifies crop evapotranspiration demand, potentially exacerbating water stress during the early stages of crop growth in April. The findings underscore the importance of addressing the substantial impacts of climate change and land use planning on regional water cycling processes. Early planning to mitigate water shortages during the initial stage of future crop growth is crucial for ensuring food security and managing water-related challenges in the NRB and neighboring mid-high latitude regions.

Seasonal and Daily Xylem Radius Variations in Scots Pine Are Closely Linked to Environmental Factors Affecting Transpiration.

Seasonal and daily radius variations in the xylem (XRV) and inner bark (IBV) of mature Scots pine trees (Pinus sylvestris) were determined during April 2019-October 2021 at a drought-prone inner alpine site (c. 750 m asl; Tyrol, Austria) by applying point dendrometers. XRVs were also related to environmental factors to evaluate the drivers of XRV during the growing season. XRV records revealed that the xylem width (i) started to shrink around the onset of radial stem growth in April, (ii) consistently decreased by c. 50 µm at the time when air temperature (T) and vapor pressure deficit (VPD) reached their maximum in late June through mid-July, and (iii) recovered until November/December. Although in daily cycles of radius variations XRV preceded IBV by about two hours and the daily amplitude of XRV was about 1/10 that of IBV, XRV and IBV (seasonal trends removed) were closely linked (ρ = 0.755; p < 0.001), indicating tight hydraulic coupling between these tissues. Furthermore, the daily amplitude of XRV was linearly and closely related to daily maximum T (ρ = 0.802; p < 0.001), mean daily solar radiation (ρ = 0.809; p < 0.001), and non-linearly related to daily maximum VPD (R2= 0.837; p < 0.001), indicating that the xylem of Pinus sylvestris reacts like a transpiration-driven passive hydraulic system.

Impact of Winter Snowfall on Vegetation Greenness in Central Asia

Snowfall is an important climatic variable with remarkable impacts on vegetation greenness in the alpine and extra-tropical regions. Central Asia (CA) is located in the middle latitude with high mountains, and the ecosystem is vulnerable to climate change in CA. In this region, the vegetation response to winter snowfall and its interactions with growing season climatic factors on vegetation greenness is still unclear. Thus, this study attempted to examine the impact of winter snowfall on vegetation greenness with remote-sensing vegetation index and reanalysis climatic data, and to investigate the interactions between winter snowfall and growing season climatic factors and their influence on vegetation growth via path analysis. The results showed that there is a generally positive correlation between winter snowfall and vegetation greenness from May to September and during the whole growing season (April to September). This positive correlation was significant in 8% of the study area for the whole growing season. However, the increase in winter snowfall was not beneficial to the regional vegetation growth in April. The vegetation response to winter snowfall also relates to land-cover type and elevation. The vegetation greenness in grassland was depicted to be more sensitive to winter snowfall than that in forestland. The response turned from positive to negative when the elevation increased from below 3000 m to above 3000 m. Moreover, the impact of winter snowfall on vegetation greenness was not regulated by temperature and precipitation in the growing season in more than 70% of CA. The impact relates to the interaction with April temperature in Central Kazakhstan, and is regulated by growing season precipitation in North Kazakhstan where annual precipitation mainly occurs in the growing season. The impact of winter snowfall on vegetation greenness is more important than growing season precipitation and temperature in some areas, since annual precipitation does not concentrate in the growing season or the relative increase of winter snowfall is great in these places. The results of the present study improve the understanding of vegetation response to climate change, and provide a scientific reference for environmental protection in CA and similar regions.

Influence of Rootstocks on Leaf Mineral Content in the Subtropical Peach cv. UFSun

The rootstock is an essential element for orchard management, influencing scion growth, nutrient concentration, and fruit quality. Seasonal variations in leaf nutrients of ‘UFSun’ grafted on five different rootstocks (‘Flordaguard’, ‘Barton’, ‘MP-29’, ‘P-22’, and ‘Okinawa’) were investigated during the 2017–18 growing season in Citra, FL. There was no significant variation in the macronutrient concentrations (N, P, K, Mg, Ca, and S) among different rootstocks; however, ‘UFSun’ on ‘Okinawa’ and ‘Flordaguard’ showed greater concentrations of Ca, K, and Mg concentration than other rootstocks. In contrast, ‘Flordaguard’ showed less potential to accumulate P as compared with other rootstocks. The Ca concentration was lowest in ‘MP-29’ and ‘Barton’ in April and June. The concentration of macronutrients (N, P, K, Mg, Ca, and S) in leaves was greater in April and October than in December and June. With respect to rootstocks, macronutrients in December and June were the highest in ‘Okinawa’ and the lowest in ‘Barton’. In April, the lowest concentration of macronutrient was recorded in ‘Barton’, whereas the highest concentrations were found in ‘P-22’, ‘Okinawa’, and ‘Flordaguard’. The highest leaf micronutrient concentrations were found in ‘MP-29’ and ‘Barton’, and the lowest in ‘Okinawa’ and ‘Flordaguard’ in June and October. For all rootstocks, concentrations of micronutrients increased between leaf growth in April and senescence in October. The micronutrient concentrations of leaves decreased during December. The widest dynamic changes during the vegetative cycle were found on ‘P-22’. Seasonal trends were more consistent for micronutrients than for macronutrients.

Comparing growth phenology of co-occurring deciduous and evergreen conifers exposed to drought

Plant phenological events are influenced by climate factors such as temperature and rainfall. To evaluate phenological responses to water availability in a Spring Heath-Pine wood (Erico-Pinetum typicum), the focus of this study was to determine intra-annual dynamics of apical and lateral growth of co-occurring early successional Larix decidua and Pinus sylvestris and late successional Picea abies exposed to drought. The effect of reduced plant water availability on growth phenology was investigated by conducting a rainfall exclusion experiment. Timing of key phenological dates (onset, maximum rate, end, duration) of growth processes were compared among species at the rain-sheltered and control plot during 2011 and 2012. Shoot and needle elongation were monitored on lateral branches in the canopy at c. 16m height and radial growth was recorded by automatic dendrometers at c. 1.3 m height of >120 yr old trees. Different sequences in aboveground growth phenology were detected among the three species under the same growing conditions. While onset of radial growth in April through early May was considerably preceded by onset of needle growth in Larix decidua (5–6 weeks) and shoot growth in Pinus sylvestris (c. 3 weeks), it occurred quite simultaneously with onset of shoot growth in Picea abies. Low water availability had a minor impact on onset of aboveground growth, which is related to utilization of stored water, but caused premature cessation of aboveground growth. At the control plot mean growing season length was 130 days in Pinus sylvestris, 95 days in Larix decidua and 73 days in Picea abies, supporting the hypothesis that early successional species are resource expenders, while late successional species are more efficient in utilizing resources and develop safer life strategies. High synchronicity found in culmination of radial growth in late spring (mid-May through early June) prior to occurrence of more favourable environmental conditions in summer might indicate sink competition for carbohydrates to belowground organs. This is supported by completion of apical growth in mid June in all species, except for needle growth of Pinus sylvestris which lasted until early August. Phenological observations of conifers exposed to drought revealed that tree water status early during the growing season determines total annual aboveground growth and, besides temperature, species-specific endogenous and/or environmental factors (most likely photoperiod and/or different threshold temperatures) are involved in controlling apical and lateral growth resumption after winter dormancy.

Soil mineral nitrogen responses following liquid hog manure application to semiarid forage lands

Bork, E. W., Lambert, B. D., Banerjee, S. and Blonski, L. J. 2013. Soil mineral nitrogen responses following liquid hog manure application to semiarid forage lands. Can. J. Soil Sci. 93: 369–378. Expansion of intensive livestock operations into semiarid regions lacking cultivated lands requires consideration of perennial forages for the efficient and sustainable disposal of manure. Little information exists on the nutrient dynamics associated with the application of manure to these areas. We examined soil mineral nitrogen (N) responses in four sites of the mixed-grass prairie, including two native grasslands and two introduced pastures, following different seasons (fall vs. spring), methods (dribble broadcast vs. coulter injected) and rates of liquid hog manure application (9.4, 18.8, 37.5, 75 and 150 kg ha−1available N). Soil mineral N, including NO3-N, NH4-N and total mineral N, were assessed after application but prior to plant growth in April 1999, and again one growing season later in April 2000. Initial soil N did not vary with season of application. Soil mineral N predictably increased with application rate, but only in the upper soil profile (0–20 cm). Decreases in soil mineral N after one growing season in all treatments highlighted the ability of these perennial forage lands to immobilize large amounts of soil N, a significant portion of which was related to N uptake by vegetation. Compared with broadcast application, manure injection led to 35% greater soil mineral N (both NO3and NH4) prior to plant growth, a response that persisted 1 yr later (+12%), thus demonstrating the N conserved benefits of manure incorporation. Overall, increases in soil mineral N within these forage lands appeared to be relatively short-term in nature, largely depleting over the course of a single growing season, suggesting one-time liquid hog manure application at low to moderate rates may be sustainable in this region of the mixed-grass prairie.

Real Economy: Trends and Factors in April 2013

The slowdown of the economic growth in April 2013 was determined by the slackening of the investment demand dynamics. In April 2013 the investments in fixed assets made 99.3%, in January-April – 99.8% of the corresponding indices of the previous year. However, the indices of the industrial production in March-April 2013 in annual terms demonstrate some growth after the recession of January-February. The growth rates of the industrial production this April in annual terms made 2.3%.

Baltic sprat larvae: coupling food availability, larval condition and survival

Eggs and larvae of Baltic sprat Sprattus sprattus L. were collected during 14 cruises covering the spawning season in 2002 in Bornholm Basin. Main egg and larval production was in April, with a second small peak in June 2002. The in situ larval abundance was corrected for trans- port processes by hydrodynamic model runs. Corrected larval abundance estimates were compared to initial larval production to derive an index of larval mortality. This index suggested a much higher survival of summer- over spring-born sprat larvae, with pronounced differences in survival for larvae >11 mm. Independent evidence for this survival pattern was gained by measured RNA:DNA ratios in sprat larvae hatched from April to July 2002 and was linked to temporal variability in potential prey abundance. We found higher mean but less variable RNA:DNA ratios in spring- than in summer-born larvae, indicating a strong selection for fast growth in April and May but a less selective environment in June and July. Zooplankton data revealed high naupliar concentrations of Acartia spp. (a key dietary component of sprat) in April and May, but very low concentrations of larger prey items such as copepodites or adults. In contrast, abundance of larger prey increased considerably in June and July. The results suggest that larger sprat (>11 mm) in April and May 2002 may have been food limited and, therefore, had lower rates of survival, supporting the underlying hypothesis of size- specific, temporally limited 'windows of survival' linked to the availability of suitable prey.

Seasonal variations in hepatic and ovarian zinc concentrations during the annual reproductive cycle in female channel catfish ( Ictalurus punctatus)

Seasonal variations in hepatic and ovarian zinc concentrations were studied during the reproductive cycle in female channel catfish ( Ictalurus punctatus). The gonadal somatic index (GSI) increased dramatically in April and peaked in June prior to spawning. Exogenous vitellogenesis was initiated in the fall as noted by increases in serum estradiol and testosterone and liver somatic index (LSI). Total hepatic zinc and zinc in the cytosolic high-molecular weight (HMW) and metallothionein-like (MT) fractions were elevated in March but decreased during rapid vitellogenic oocyte growth in April and May. Following spawning in July, total hepatic zinc and zinc in the HMW and MT-like fractions were again elevated. Total ovarian zinc and zinc associated with HMW and MT-like fractions increased with GSI, then decreased to a low after spawning. However, on a per g tissue basis, ovarian zinc concentrations in both cytosolic pools declined during rapid oocyte growth, indicating a different intracellular localization of the zinc binding proteins. Hepatic MT-like proteins exhibit UV absorption profiles similar to mammalian MT while the ovarian proteins appear to be different. Results give evidence for the homeostatic regulation of hepatic zinc by MT during exogenous vitellogenesis and a similar function for the ovarian MT-like protein during oocyte development.

Zebra mussel (Dreissena polymorpha) seasonal colonization patterns in a sub-tropical floodplain river

Zebra mussel (Dreissena polymorpha) seasonal colonization patterns, growth and habitat preferences were determined in a sub-tropical floodplain river at the southern edge of its distribution in North America during 1995–96 (Atchafalaya River Basin, Louisiana). Zebra mussel movement into subtropical areas represents a major frontier for this species worldwide. The onset of adult zebra mussel colonies occurred when the minimum daily temperature dropped below 31 °C and dissolved oxygen levels rose above 6.5 mg l-1 in the fall. By mid-winter, mussel populations were established at lateral distances >10 km from the main river channel. Mussel growth occurred throughout the winter with an increase in growth in April and May. Adult mortality occurred during May–August as dissolved oxygen levels declined and minimum daily temperature warmed above 29 °C in the floodplain and 32.5 °C in riverine sites. Limiting factors responsible for the seasonal pattern include temperature and dissolved oxygen tolerances experienced during summer months in the ARB. Summer water conditions apparently preclude establishment of resident zebra mussel populations in the Atchafalaya floodplain. Naturally occurring seasonal patterns in temperature and dissolved oxygen in floodplain rivers may have implications for the expansion of this exotic mollusk in warmwater systems with source colonies restricted to mainstem rivers and seasonal sinks in floodplain regions.

Life history patterns of the common carp, Cyprinus carpio, in the estuary of the Guadalquivir river in south-west Spain

We examined 1567 carp caught in rice field drainage canals in the estuary of the Guadalquivir river (37° N, 6° 25′ W). The stock was comprised of a small number of age groups, among which 0+ and 1+ were dominant. Growth was divided in four periods: rapid (June–July); slow (August–November), no growth (December–March), and resumed growth in April when an annulus was formed. A classification based on 12 wild carp populations revealed that growth depends on latitude, and that growth of the studied stock was mediocre, probably due to high salinity. A decrease in somatic condition coincided with an increase in gonadosomatic index (GSI). Specimens of the same stock, age and/or length showed considerable difference in development of the gonads. Gonadal activity began in September and by late Autumn some gonads had reached up to 20% of body weight. The situation remained static during Winter till April, when most reproduction occurred. Later, GSI values decreased to reach a minimum in September. Maximum average GSI values in females were twice those in males. Both sexes achieved maturity during the third growing season (2+ age-group) at a minimum fork length (F.L.) of 110 mm. Fecundity, before reproduction, was expressed by Fec = 241.701 F.L. (mm) − 26776.2. The sex ratio did not differ significantly from 1 : 1.

Variability of Crude Protein in Crested Wheatgrass at Defined Stages of Phenology

Variability of crude protein concentration in crested wheatgrass (Agropyron desrrtorwn (Fisch. ex Link)Schult) is an important consideration in the development of graxing programs. Crude protein (CP) concentration in crested wheatgrass was monitored at specific stages of phenology for 5 years. During that time Sep tember through August precipitation varied from 68 to 142% of the 37-year mean. Vegetation was clipped once at 10 phenological stages beginning in April. At the last clipping date, in mid-August, regrowth accumulated after prior clippings was collected. Over the 5-year period, CP of vegetation clipped during mid vegetative growth in late April varied 35%, relatively, from 14.7% in 1983 to 9.5% during 1985. Even though 1984 crop year precipitation exceeded 1983 by 84 mm, maximum topgrowth biomass was 449 kg/ha lower in 1984. Also, CP percentage of vegetative growth in April was 1.8% lower in 1984 than in 1983. Regrowth CP was positively correlated (r=0.98) with June precipitation, and with the number of rain events in July (r=0.97). Plants clipped in the boot stage had greater forage CP in August than plants clipped prior to boot stage. However, regrowth biomass was affected by soil water availability and was highly variable. Crude protein in vegetative growth was marginal for growing steers in 1985. Although growing stock are often supplemented in late summer, these data are htterpreted to show that spring supplementation may be needed some years.

Advancement of sexual maturation and spawning of sea bass, Lates calcarifer (Bloch), using pelleted luteinizing hormone-releasing hormone analogue and 17 α-methyltestosterone

The ability of luteinizing hormone-releasing hormone analogue [(D-Ala 6,Pro 9-NEt)LHRH], 17 α-methyltestosterone (MT), and their combination to advance gonadal maturation and spawning in captive sea bass ( Lates calcarifer Bloch) broodstock was tested. Several hormonal therapies were tested including monthly implantations of a low dose (100 μg/kg body weight) of each hormone and a high dose (200 μg/kg) implanted to sexually-quiescent sea bass at 45-day intervals. A high dose of LHRHa alone or in combination with MT induced a significant number of mature females (43–71%) in April, 45 days after a single implantation in early March. A lower dose of pelleted LHRHa and LHRHa plus MT was found effective (78–80%) only in May following three monthly implantations. Two and three monthly implantations of a low dose of MT failed to stimulate oocyte growth in April and May whereas a less frequent mode of application of a high dose of the androgen inhibited ovarian growth in April only. A low dose of MT alone significantly increased the number of mature males in April (90%) and May (100%) after two and three monthly implantations. All male sea bass which received three monthly implantations of a low dose of LHRHa and LHRHa plus MT were sexually mature in May. Sexually mature sea bass obtained from these experiments spawned in early May after a single intramuscular injection of LHRHa. These results demonstrate the potential use of pelleted LHRHa and MT to significantly advance gonadal development and spawning in sea bass earlier than the annual breeding season.

Seasonal fleece changes in two selection lines of Scottish Blackface sheep during their lifetime on the hill

SUMMARYTen Scottish Blackface ewes from each of three lines, a line selected for hairiness, a line selected for a fine fleece, and an unselected control, were fleece and skin sampled in April, June, September and December, during their 6J year life-span on the hill.Fleece weight differed between individuals and between lines, and declined by 4% per year from 1·5 kg at 1 year, to 1·3 kg at 6 years. Fleece grade was inadequate as a method of denning fleece differences between the lines.The height of the spring ‘rise’ in growth in April differed between years, and between lines, declining 2 mm a year from 26 mm at 1 year. Staple length was greatest in the Hairy group and least in the Fine group (P &lt; 0·05). Growth in length was faster between September and December (autumn) than between April and June (spring). Staple length decreased by 14 mm a year.The lines differed significantly (P &lt; 0·05) in mean fibre diameter but not in modal fibre diameter. There was a highly significant decrease in diameter from summer to winter, ranging from 20% in the Fine line to 31% in the Hairy line, the greater decrease in the Hairy line being attributed to loss of medulla.The selection had between 1954 and 1972 changed the S/P follicle ratio of 3·0 in the control to 2·8 in the Hairy line and 3·2 in the Fine line. Most seasonal follicle inactivity occurred in April, December came second, and June invariably had more follicle inactivity than September. The control line had the greatest values of primary follicle inactivity and the Fine least. Among the secondary follicles the Hairy line had most inactivity, and the control line least. Maximum primary fibre medullation occurred in either June or September, and medullation was at a minimum in December or April.

Factors Influencing the Survival of Propagules of Tall Fescue (Festuca arundinacea Schreb.)

SUMMARYPropagules of five tall fescue genotypes, planted monthly, from April to December, made the greatest growth in April and September and the least in December. Despite the diverse geographic origin of the genotypes, there was no indication of interaction between genotypes and daylength. Propagules grew more vigorously when cut just above the basal leaf sheath then when cut to two or three inches in length. The complete removal of roots, which would facilitate planting, did not reduce growth and appeared to enhance the development of new roots. Propagules consisting of two or three culms grew more vigorously than those consisting of a single culm. Accordingly, if propagules were fragile or if survival was poor, two-culm propagules would become established more readily. Genotypes differed in growth rate even when planting weights were kept uniform. Results of this study could be used to reduce the time and cost of vegetative propagation of tall fescue.

Studies on the Fertilization and the Seed Formation of the Tea Plant

Double fertilization : The pollen tubes entered into the embryosac and the mail gametes were situated close to the egg cell or the pollar nuclei in about 2-5 days after pollination. The male nucleus came into contact with the egg cell and on the other hand, the triple fusion was comleted in about 5-8 days. The male and egg nuclei were situated confronting each other within the egg cell, and the first division of the primary endosperm nucleus took place in about 8-13 days. The male nucleus in the egg cell grew as large as the egg nucleus and four endosperm nuclei were formed by the second division in about 13 days. The male nucleus in the egg cell was seen as the fused nucleus, and nuclear division was repeated more than three times in about 20 days. It was 35 days after pollination that, the first mitosis occurred in the fertilized egg cell.The maximum percentage of fertilization was seen in 8 days after pollination, and the percentage of normal ovules amounted to 50-60% in each reciprocal crossing of Yabukita and Sayamamidori. The process of collapse of auxiliary cells varied according to individuals, so, to know the success of fertilization it was thought to be desirable to judge it from the conditions of egg cell and pollar nuclei.Formation of seeds in-the fruit : One ovary involved about 12 ovules, but the average numder of seeds in one fruit was three in common varieties. This was due both to the low fertilization percentage and to the occurrence of many abortive seeds which was seen 13 days after pollination. The definite causes that the number of seeds in a fruit varied among varieties were thought to be either the failure of fertilization or the degeneration of fertilized ovules.Fruit drop : The fertilization percentage was very high in every variety, so the cause of fruit drop was thought to be scarcely due to fertilization' failure. The fruit drop rate till March was comparatively low. Early stage of fruit growth in April and May corresponded just to the first growth period of tea shoots, and fruit drop in this period fairly increased in every variety. But after this time, the percentage of fruit drop was very different among varieties. In common varieties, the fruit drop continued up to the autumn, but in well seed setting varieties it seldom occurred when the flowers were open pollinated; the fruit drop habit was observed to be similar to that of non-pollinated fruits, so it was considered that the low percentage of fruit setting in open pollinated plant was largely due to the fertilization failure.